INSTRUCTION MANUAL
IN 213 Rev. A 12/02
Providing Exceptional Consumer Optical Products Since 1975
Customer Support (800)676-1343
E-mail: support@telescope.com
Corporate Offices (831)763-7000
P.O. Box 1815, Santa Cruz, CA 95061
Orion
®
Atlas™8 EQ
#9873 Equatorial Reflector Telescope
2
Figure 1. The Atlas 8 EQ.
Tube ring mounting plate
Tube ring mounting plate
lock knobs (2)
Declination setting circle
Declination lock lever
Counterweight shaft lock lever
Counterweight shaft
Counterweights
Counterweight
lock knobs
“Toe Saver”
Tripod leg
Leg lock lever
Finder scope
Finder scope bracket
Eyepiece
Focus knob
Tube rings
Right ascension
setting circle
Right ascension lock lever
Mirror cell
Latitude scale
Latitude adjustment L-bolts
Center support shaft
(not shown)
Hand controller
Tripod support tray
3
Table of Contents
1. Unpacking . . . . . . . . . . . . . . . . . . . . . . . 3
2. Parts List . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Assembly . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Balancing the Telescope . . . . . . . . . . . . 5
5. Using Your Telescope . . . . . . . . . . . . . . . 6
6. Setting Up and Using
the Equatorial Mount . . . . . . . . . . . . . . . 7
7. Collimating . . . . . . . . . . . . . . . . . . . . . . 12
8. Astronomical Observing . . . . . . . . . . . . 14
9. Astrophotography . . . . . . . . . . . . . . . . . 17
10. Care and Maintenance . . . . . . . . . . . . . 18
11. Specifications . . . . . . . . . . . . . . . . . . . . 19
1. Unpacking
The entire telescope will arrive in three boxes, one containing
the tripod, one containing the equatorial mount, and the third
box containing the optical tube. Be careful unpacking the
boxes.We recommend keeping the boxes and original packaging. In the event that the telescope needs to be shipped to
another location, or returned to Orion for warranty repair, hav-
ing the proper packaging will ensure that your telescope will
survive the journey intact.
Make sure all the parts in the Parts List are present. Be
sure to check each box carefully, as some par ts are small.
If anything appears to be missing or broken, immediately
call Orion Customer Support (800-676-1343) or email
support@telescope.com for assistance.
2. Parts List
Box #1
1 Tripod
2 Counterweights
1 Tripod support tray
Box #2
1 Equatorial mount
1 Hand controller
1 Battery pack
1 Nylon hook and loop adhesive strip
Box #3
1 Optical tube
2 Tube rings
1 Tube ring mounting plate
1 25mm Sirius Plössl eyepiece
1 10mm Sirius Plössl eyepiece
1 9x50 Finder scope
1 Finder scope bracket with O-ring
1 Collimation cap
1 Camera adapter
1 Dust cover
Congratulations on your purchase of a quality Orion telescope. Your new Atlas 8 EQ is designed for
high-resolution viewing of astronomical objects.With its precision optics, and its superb Atlas mount,
you’ll be able to locate and enjo y hundreds of f ascinating celestial deniz ens , including the planets, Moon,
and a variety of galaxies, nebulas, and star clusters.
These instructions will help you set up and properly use your telescope. Please read them over thoroughly before getting started.
WARNING: Never look directly at the Sun
through your telescope or its finder scope—even
for an instant—without a professionally made
solar filter that completely covers the front of the
instrument, or permanent eye damage could
result.Young children should use this telescope
only with adult supervision.
Figure 1b. The Atlas 8 EQ mount.
Power cord
jack
Power
indicator light
Hand
controller
jack
Right
ascension
setting circle
Right
ascension
lock lever
4
3. Assembly
Assembly should take no more than 30 minutes. Refer to
Figure 1 during assembly. Assembling the telescope requires
no tools other than the ones provided.
1. Stand the tripod legs upright and spread the legs out as far
as they will go. Make certain that the leg lock levers are
tightened. Keep the tripod legs at their shortest (fully
retracted) length, for now.
2. Place the base of the equatorial mount onto the tripod
head. Orient the equator ial mount so that the post on the
tripod head lines up with the azimuth adjustment knobs on
the equatorial mount (Figure 2).You may need to loosen
the azimuth adjustment knobs on the equatorial mount in
order to fit the mount onto the tripod head.
3. Thread the central support shaft into the equatorial mount
until tight.This will secure the equatorial mount to the tripod head.
4. Remove the knob and washer from the bottom of the center support shaft. Slide the tripod support tray up the bottom of the central support shaft until the three tray arms
are touching the legs of the tripod.The flat side of the support tray should be facing up. Make sure the “V” of each
tray arm is against a tripod leg. Place the knob washer on
the center support shaft against the tray, and follow it by
threading the securing knob all the way up the center support shaft until it is tight against the tray.The tripod support
tray provides additional stability f or the tripod, and holds up
to five 1.25" eyepieces and two 2" eyepieces.
5. Loosen the counterweight shaft lock lever and let the
counterweight shaft extend into its downward position.
Retighten the lock leve r.
6. Remove the knurled “toe saver”retaining screw on the bottom of the counterweight shaft and slide both counterweights onto the shaft. Make sure the counterweight lock
knobs are adequately loosened to allow the counterweight
shaft to pass through the hole.Position the counterweights
about halfway up the shaft and tighten the lock knobs.
Replace the toe saver at the end of the bar.The toe saver
prevents the counterweights from falling on your foot if the
lock knobs happen to come loose.
7. Loosen and open the tube rings on the optical tube and
remove the optical tube from the tube rings. Attach the
tube rings to the mounting plate with the provided screws.
Loosen the two mounting plate securing knobs. Place the
mounting plate with the tube rings attached in the dovetail
slot on top of the equatorial mount. Position the mounting
plate so that it is centered on the dovetail slot.Re-tighten
the mounting plate securing knobs until the mounting plate
is secure. Please note that the actual tube ring mounting
plate will be shorter than the one shown in Figure 1.
8. Open the tube rings and lay the telescope optical tube in
the rings at about the midpoint of the tube’s length.Rotate
the tube so that the focuser is at a convenient height for
viewing.Close the tube rings and tighten them.
9. Inser t the plug on the end of the control cable from the
hand controller into its jack on the side of the EQ mount.
10.Inser t eight D-cell batteries into the battery pack. Or ient
the batteries as indicated on the white plastic battery holder.Plug the battery cord into its jack on the mount.
11.Two strips of nylon adhesive (one strip of “hooks”and one
strip of “loops”) have been provided so you can create a
Finder scope
Finder scope bracket
Nylon
alignment
thumbscrews
Focus lock ring
Figure 3a. The 6x30 finder scope.
Tensioner
Figure 2. Orient the equatorial head so that the post on the tripod
lines up with the azimuth adjustment knobs on the equatorial mount.
Azimuth
adjustment
knobs
Post
Figure 3b.
Pull back on
the tensioner
and slide the
finder scope
into its
bracket until
the O-ring is
seated in the
bracket ring.
5
place to keep the hand controller out of the way when not in
use.Place the “hooks” strip of nylon adhesive on the back of
the hand controller and the “loops”strip on a tripod leg or on
the mount where it will be in a conveniently reached spot.
Simply hang the hand controller by the nylon adhesive
when it is not in use. Make certain when you attach the
nylon adhesive to the mount that the hand controller’s position will not interfere with the motion of the mount.
Installing the Finder Scope
To place the finder scope (Figure 3a) in the finder scope bracket, unthread the two black nylon thumbscrews until the screw
ends are flush with the inside diameter of the bracket. Place
the O-ring that comes on the base of the bracket over the body
of the finder scope until it seats into the slot on the middle of
the finder scope. Slide the eyepiece end (narrow end) of the
finder scope into the end of the bracket’s cylinder opposite the
alignment screws while pulling the chrome, spring-loaded tensioner on the bracket with your fingers (Figure 3b).Push the
finder scope through the bracket until the O-ring seats just
inside the front opening of the bracket cylinder. Release the
tensioner and tighten the two black nylon thumbscrews a couple of turns each to secure the finder scope in place.Insert the
base of the finder scope bracket into the dovetail holder on the
optical tube near the focuser. Lock the bracket into position by
tightening the knurled thumbscrew on the dovetail holder.
Inserting the Eyepiece
Loosen the thumbscrew on the 1.25" adapter (Figure 4) and
remove the small dust cap.Insert the 25mm eyepiece into the
focuser and secure it with the thumbscrew.
Your Atlas 8 EQ is now fully assembled and should resemble
Figure 1. Keep the dust cover on the front of the telescope
when it is not is use.
Note about the Atlas 8 EQ Mount Weight
The Atlas 8 EQ mount is very heavy. Alone it weighs 54 lbs.
With the optical tube and counterweights it weighs almost 100
lbs. Keep this in mind when moving the telescope even small
distances, and use assistance when needed. It is best to
remove the optical tube and counterweights when moving the
mount, or extending the tripod legs.
4. Balancing the Telescope
To ensure smooth movement of the telescope on both axes of
the equatorial mount, it is imperative that the optical tube is properly balanced.We will first balance the telescope with respect to
the right ascension (R.A.) axis, then the declination (Dec.) axis.
1. Keeping one hand on the telescope optical tube, loosen
the R.A.lock lever.Make sure the Dec. lock lever is locked,
for now.The telescope should now be able to rotate freely
about the right ascension axis. Rotate it until the counterweight shaft is parallel to the ground (i.e., horizontal).
2. Now loosen the counterweight lock knobs and slide the
weights along the shaft until they exactly counterbalance
the telescope (Figure 5a). That’s the point at which the
shaft remains horizontal even when you let go with both
hands (Figure 5b).
3. Retighten the counterweight lock knobs.The telescope is
now balanced on the right ascension axis.
4. To balance the telescope on the declination axis, first tighten the R.A. lock lever, with the counterweight shaft still in
the horizontal position.
Figure 5a-d. Proper operation of the equatorial mount requires
that the telescope tube be balanced on the R.A. and Dec. axes. (a)
With the R.A. lock lever released, slide the counterweights down the
counterweight shaft until they just counterbalance the telescope
tube. (b) When you let go with both hands, the tube should not drift
up or down. (c) With the Dec. lock lever released, loosen the tube
ring lock clamps a few turns and slide the telescope forward or back
in the tube rings. (d) When the tube is balanced about the Dec. axis,
it will not move when you let go.
a. b.
c.
d.
Figure 4. The 2" focuser of the Atlas 8 EQ.
Focus lock
thumbscrew
Focus
knobs
1.25" eyepiece
adapter
2" eyepiece adapter
Collimation
screw pair
(3)
6
5. With one hand on the telescope optical tube, loosen the
Dec.lock lev er.The telescope should now be able to rotate
freely about the declination axis.
6. Loosen the knurled ring clamps on the tube r ings a few
turns, until you can slide the telescope tube forward and
back inside the rings (this can be aided by using a slight
twisting motion on the optical tube while you push or pull
on it) (Figure 5c).
7. Position the telescope in the tube rings so it remains horizontal when you carefully let go with both hands.This is
the balance point for the optical tube with respect to the
Dec. axis (Figure 5d).
8. Retighten the knurled rings clamps.
The telescope is now balanced on both axes. When you
loosen the lock lever on one or both axes and manually point
the telescope, it should move without resistance and should
not drift from where you point it.
5. Using Your Telescope
Focusing the Telescope
With the 25mm eyepiece inserted in the focuser, loosen the
R.A. and Dec. lock levers and move the telescope so the front
(open) end is pointing in the general direction of an object at
least 1/4-mile away. Now, with your fingers, slowly rotate one
of the focusing knobs until the object comes into sharp focus.
Go a little bit beyond sharp focus until the image just starts to
blur again, then reverse the rotation of the knob, just to make
sure you’ve hit the exact focus point.
NOTE: The image in the telescope will appear rotated
180° (upside down and reversed left-to-right).This is normal for astronomical scopes.The finder scope view will
also be rotated 180° (see Figure 6).
If you have trouble focusing, rotate the focusing knob so the
drawtube is in as far as it will go .Now look through the eyepiece
while slowly rotating the focusing knob in the opposite direction.
You should soon see the point at which focus is reached.
The black nylon thumbscrew on the top of the body of the
focuser (see Figure 4) will lock the focuser drawtube in place
once the telescope is properly focused. Before focusing,
remember to first loosen this thumbscrew.
Viewing with Eyeglasses
If you wear eyeglasses, you may able to keep them on while
you observe, if the eyepiece has enough “eye relief” to allow
you to see the whole field of view.You can try this by looking
through the eyepiece first with your glasses on, and then with
them off, and see if the glasses restrict the view to only a portion of the full field.If they do, you can easily observe with your
glasses off by just re-focusing the telescope the needed
amount. If you suffer from severe astigmatism, however, you
may find images noticeably sharper with your glasses on.
Aligning the Finder Scope
The Atlas 8 EQ Deluxe comes with a 6x30 achromatic finder
scope (Figure 3a).The number 6 means six-times magnification and the 30 indicates a 30mm diameter front lens. The
finder scope makes it easier to locate the subject you want to
observe in the telescope, because the finder scope has a
much wider field-of-view.
The Atlas 8 EQ’s finder scope uses a spring-loaded brack et that
makes alignment of the finderscope very easy. As you turn
either of the thumbscrews, the spring in the bracket’s tensioner
moves in and out to keep the finder scope secure in the brac k et.
The finder scope must be aligned accurately with the telescope for proper use.To align it, first aim the main telescope
in the general direction of an object at least a 1/4 mile away—
the top of a telephone pole, a chimney, etc; loosen the R.A.
and Dec. lock levers and move it until it is pointing at the
desired object.Then sight along the tube to precisely aim the
telescope. Turn the focus knob until the object is properly
focused.Retighten the R.A. and Dec. lock levers.
Now look in the finder scope.Is the object visible? Ideally it will
be somewhere in the field of view. If not, some coarse adjustment to the finder scope bracket’s alignment thumbscrews will
be needed until the object comes into the finder scope’s field
of view.
With the image in the finder scope’s field of view, you now
need to fine-adjust the alignment thumbscrews to center the
object on the intersection of the crosshairs. Adjust the aim of
the finder scope by turning the thumbscrews, one at a time,
until the object is centered.
The finder scope alignment needs to be checked before every
observing session. This can easily be done at night, before
viewing through the telescope.Choose any bright star or planet, center the object in telescope eyepiece, and then adjust
the finder scope bracket’s alignment thumbscrews until the
star or planet is centered on the finder’s crosshairs.
Focusing the finder scope
If, when you look through the finder scope, the images appear
somewhat out of focus, you will need to refocus the finder
scope for your eyes. Loosen the lock ring located behind the
objective lens cell on the body of the finder scope (see Figure
Naked-eye view
View through finder scope and telescope
Figure 6. The view through a standard finder scope and reflector
telescope is rotated 180°.This is tr ue for the Atlas 8 EQ and its
finder scope as well.
7
3a). Back the lock ring off by a few turns, for now.Refocus the
finder scope on a distant object by threading the objective
lens cell in or out of the finderscope body .Precise focusing will
be achieved by focusing the finder scope on a bright star.
Once the image appears sharp, retighten the locking ring
behind the objective lens cell.The finder scope’s focus should
not need to be adjusted again.
Magnification & Eyepieces
Magnification, or power, is determined by the focal length of
the telescope and the focal length of the eyepiece.Therefore,
by using eyepieces of different focal lengths, the resultant
magnification can be varied.
Magnification is calculated as follows:
Telescope Focal Length (mm)
= Magnification
Eyepiece Focal Length (mm)
The Atlas 10 EQ has a focal length of 1200mm, which when
used with the supplied 25mm eyepiece yields a magnification of:
1000mm
= 40x
25mm
The magnification provided by the 10mm eyepiece is:
1000mm
= 100x
10mm
The maximum attainable magnification for a telescope is directly related to how much light it can gather.The larger the aperture, the more magnification is possible.In general a figure of
60x per inch of aperture is the maximum attainable for most telescopes.Your Atlas 8 EQ has an aperture of 8 inches, so the
maximum magnification would be about 480x. This level of
magnification assumes you have ideal conditions for viewing.
Keep in mind that as you increase magnification, the brightness
of the object viewed will decrease; this is an inherent principle
of the laws of physics and cannot be av oided.If magnification is
doubled, an image appears four times dimmer. If magnification
is tripled, image brightness is reduced by a factor of nine!
Always start with your lowest power eyepiece and work your
way up. Start by centering the object being viewed in the
25mm eyepiece.Then you may want to increase the magnification to get a closer view. If the object is off-center (i.e., it is
near the edge of the field of view) you will lose it when you
increase magnification since the field of view will be narrower
with the higher-powered eyepiece. To change eyepieces, first
loosen the securing thumbscrew on the focuser’s 1.25"
adapter.Then carefully lift the eyepiece out of the holder.Do
not tug or pull the eyepiece to the sides, as this will knock the
telescope off its target. Replace the eyepiece with the new
one by sliding it gently into the holder.Re-tighten the thumbscrew, and refocus for your new magnification.
Using 2" eyepieces
The Atlas 8 EQ’s focuser is capable of accepting optional 2"
eyepieces.To use 2" eyepieces you must remove the 1.25"
adapter from the focuser by loosening the two thumbscrews
that hold it in place (Figure 4). Once this adapter is removed,
insert a 2" eyepiece into the focuser and use the same thumbscrews to secure the larger eyepiece.
6. Setting Up and Using the
Equatorial Mount
When you look at the night sky, you no doubt have noticed
that the stars appear to move slowly from east to west over
time.That apparent motion is caused by the Earth’s rotation
(from west to east). An equatorial mount (Figure 7) is
designed to compensate for that motion, allowing you to easily “tr ack”the movement of astronomical objects, thereby k eeping them from drifting out of your telescope’s field of view
while you’re observing.
This is accomplished by slowly rotating the telescope on its
right ascension (R.A.) axis, using the built in motor drive.But
first the R.A.axis of the mount must be aligned with the Earth’s
rotational (polar) axis—a process called polar alignment.
Figure 7. The Atlas EQ Mount.
Dec. lock lever
Dec. setting circle
Front opening
Azimuth adjustment knobs (2)
R.A. setting circle
R.A. lock lever
Polar axis finder
scope
Latitude scale
Latitude
adjustment L-bolts
Right
Ascension
(R.A.) axis
Declination (Dec.) axis
x
.) a
c
(De
n
linatio
c
De
A
(R.A.) a
is
R
ig
s
c
h
e
n
s
io
x
is
t
n
8
Polar Alignment
For Northern Hemisphere observers, approximate polar alignment is achieved by pointing the mount’s right ascension axis
at the North Star, or Polaris.It lies within 1° of the north celestial pole (NCP), which is an extension of the Earth’s rotational
axis out into space.Stars in the Northern Hemisphere appear
to revolve around the NCP.
To find Polaris in the sky, look nor th and locate the patter n of
the Big Dipper (Figure 8). The two stars at the end of the
“bowl” of the Big Dipper point right to Polaris.
Observers in the Southern Hemisphere aren’t so fortunate to
have a bright star so near the south celestial pole (SCP).The
star Sigma Octantis lies about 1° from the SCP, but it is barely
visible with the naked eye (magnitude 5.5).
For general visual observation, an approximate polar alignment is sufficient.
1. Level the equatorial mount by adjusting the length of the
three tripod legs.Temporarily remove the optical tube and
counterweights from the mount before attempting to do this.
2. There are two altitude adjusting L-bolts (see Figure 7);
loosen one while tightening the other.By doing this you will
adjust the latitude of the mount. Continue adjusting the
mount until the pointer on the latitude scale is set at the latitude of your observing site.If you don’t know your latitude,
consult a geographical atlas to find it. For example, if your
latitude is 35° North, set the pointer to 35.The latitude setting should not have to be adjusted again unless you mo v e
to a different viewing location some distance away.
3. Loosen the Dec. lock lever and rotate the telescope’s opti-
cal tube until it is parallel with the right ascension axis, as
it is in Figure 7.
4. Move the tripod so the telescope tube and right ascension
axis point roughly at Polaris. If you cannot see Polaris
directly from your observing site, consult a compass and
rotate the tripod so the telescope points north.
The equatorial mount is now polar aligned for casual observing.
More precise polar alignment is recommended for astrophotography. For this we recommend using the polar axis finder scope
From this point on in your observing session, you should not
make any further adjustments to the latitude of the mount, nor
should you move the tripod.Doing so will undo the polar alignment.The telescope should be moved only about its R.A. and
Dec. axes.
Using the Polar Axis Finder Scope
The Atlas EQ mount comes with a polar axis finder scope
(Figure 9) housed inside the right ascension axis of the
mount. When proper ly aligned and used, it makes accurate
polar alignment quick and easy to do.
Alignment of the Polar Axis Finder Scope
1. Loosen the Dec. lock lever and rotate the optical tube on
the declination axis so that the tube is at a 90° to the right
ascension axis (Figure 10).Tighten the Dec. lock lever.
2. Look through the polar finder at a distant object (during the
day) and center it in the crosshairs.Y ou ma y need to adjust
the latitude adjustment L-bolts and the tripod position to do
this.
3. Rotate the mount 180° about the R.A. axis. Again, it may
be convenient to remove the counterweights and optical
tube first.
4. Look through the polar finder again. Is the object being
viewed still centered on the crosshairs? If it is, then no further adjustment is necessary.If not, then look through the
polar finder while rotating the mount about the R.A. axis.
You will notice that the object you have previously centered
moves in a circular path. Use the three alignment
setscrews on the polar axis finder (Figure 9) to redirect the
crosshairs of the polar finder to the apparent center of this
circular path. Repeat this procedure until the position that
the crosshairs point to does not rotate off-center when the
mount is rotated in R.A.
The polar axis finder scope is now ready to be used.When not
in use, replace the plastic protective cov er to pre v ent the polar
finder from getting bumped.
Using the Polar Axis Finder Scope
The reticle of the polar axis finder scope for the Atlas has a
tiny star map printed on it that makes precise polar alignment
Figure 9. The optional polar axis finder scope.
Eyepiece
focus ring
Alignment
setscrew (3)
Focus
lock ring
Objective
lens
Figure 8. To find Polaris in the night sky, look north and find the
Big Dipper.Extend an imaginar y line from the two “Pointer Stars” in
the bowl of the Big Dipper.Go about five times the distance between
those stars and you'll reach Polaris, which lies within 1° of the north
celestial pole (NCP).
Big Dipper
(in Ursa Major)
Little Dipper
(in Ursa Minor)
Cassiopeia
N.C.P.
P
ointer
S
ta
rs
Polaris
9
quick and easy.To align the mount using the polar axis finder
scope, follow these instructions:
1. Approximately polar-align the mount as outlined in the procedure previously.
2. Loosen the Dec. lock lever and rotate the optical tube on
the declination axis so that the tube is at a 90° to the right
ascension axis (Figure 10).Tighten the Dec. lock lever.
3. Remove the cap on the front opening of the equatorial
mount (Figure 7). Focus the polar finder by rotating the
eyepiece.Now, sight Polaris in the polar axis finder scope.
If you have followed the approximate polar alignment procedure accurately, Polaris will probably be within the field
of view. If not, move the tripod left-to-right, and adjust the
latitude up-and down until Polaris is somewhere within the
field of view of the polar axis finder scope.
4. Flip the power switch on the hand controller to the N or S
position.With the power on you can now use the illuminator
on the polar axis reticle. Look through the polar axis finder
and adjust the illuminator by turning the dial on the mount
(located above the power and hand controller jacks) counter-clockwise to make it brighter, and clockwise to make it
dimmer.Use the dimmest possible setting that allows you to
see the reticle without difficulty. Note the constellation
Cassiopeia and the Big Dipper in the reticle. They do not
appear in scale, but they indicate the general positions of
Cassiopeia and the Big Dipper relative to the north celestial
pole (which is indicated by the cross at the center of the reticle).Rotate the reticle so the constellations depicted match
their current orientation in they sky when viewed with the
naked eye.To do this, release the R.A. lock lever and rotate
the main telescope around the R.A. axis until the reticle is
oriented with sky. For larger optical tubes, you may need to
remove the tube from the mount to prevent it from bumping
into the mount.Once the reticle is correctly oriented, use the
right ascension lock lever to secure the mount’s position.
5. Now use the azimuth adjustment knobs (Figure 2) and the
latitude adjustment L-bolts (Figure 7) on the mount to posi-
tion the star Polaris inside the tiny circle marked “Polaris”
on the finder’s reticle.You must first loosen the knob underneath the equatorial mount on the center support shaft to
use the azimuth adjustment knobs.Once Polaris is properly positioned within the reticle, you are precisely polar
aligned. Retighten the knob underneath the mount.
If you do not have a clear view of Polaris from your observing
site, you will not be able to use the polar-axis finder to precisely polar align the telescope.
Note: From this point on in your observing session, you
should not make any further adjustments in the azimuth
or the latitude of the mount, nor should you move the tripod. Doing so will undo the polar alignment. The telescope should be moved only about its right ascension
and declination axes.
Additional Note Regarding Focusing the Polar
Axis Finder Scope
The polar axis finder scope is normally focused by simply
rotating the eyepiece focus ring.However, if after adjusting the
focus ring you find that the image of the reticle is sharp, but
the stars are out of focus, then you must adjust the focus of
the polar axis finder’s objective lens. To do this, first remove
the polar axis finder from the mount. Look through the polar
axis finder at a star (at night) or distant object at least 1/4 mile
away (during daylight). Use the eyepiece focus ring to bring
the reticle into sharp focus. Now, loosen the focus lock ring
(Figure 9) and thread the entire objective end of the finder
inwards or outwards until images appear sharp.Re-tighten the
focus lock ring. Once the polar axis finder’s objective lens is
focused, it should not need to be adjusted again.
Operation of the Atlas Mount Motor Drives
The Atlas EQ mount comes with dual built-in motor drives.
These motor drives will be used to “track”objects in the night
sky, as well as to make small adjustments when aiming the
telescope.The motors are controlled from the hand controller
(Figure 11). To start the drives, flip the power switch on the
Figure 10. The optical tube must be at a 90° angle to the R.A.
axis in order to view through the polar axis finder.
Figure 11. The Atlas EQ Mount hand controller.
Indicator light
R.A.
pushbuttons
Reverse
switches
Dec.
pushbuttons
Power switch Rate switch
10
hand controller to “N”if you live in the northern hemisphere, or
“S” if you live in the southern hemisphere.When you flip the
power switch, the power indicator light on the mount will glow
red and the power indicator light on the hand controller will
glow green. Your mount will now be moving at the sidereal
rate, which is the same rate as the sky’s apparent motion. If
the mount is properly polar aligned, the mount will be “track-
ng” the motion of astronomical objects as the Earth rotates.
To move your telescope to a new object, loosen both the R.A.
and Dec. lock levers and move the telescope until it is pointed
in the general direction of the object you wish to view .Retighten
the R.A and Dec. lock levers.To center the object in the eyepiece’s field of vie w, you will need to use the hand controller.
There are four pushbuttons on the hand controller. If no buttons are pushed, the R.A. motor will tur n on the R.A. axis at
sidereal rate to track the motion of the night sky. The left and
right buttons move the mount about its R.A.axis, and the up
and down buttons move the mount about its Dec. axis. The
rate of speed is determined by the rate switch at the top right
of the hand controller. If the switch is at the 2x position, the
mount will move at two times sidereal rate when the right hand
button is pushed, which will cause objects to viewed in the
eyepiece to mov e slo wly eastw ard.If the left button is pushed,
the drive will stop turning, which will cause objects in the eyepiece to move slowly westward. The top and bottom bottoms
will cause the telescope to move north and south in Declination at the 2x speed. Similarly, if the rate switch is at the 8x or
16x position, the mount will move eight times or sixteen times
sidereal rate when a button is pushed.
The 2x sidereal rate is the best setting for making guiding corrections during long-exposure astrophotography. The 8x and
16x rates are best for centering an object within the telescope’s eyepiece or finder scope.
Note that whenever any of the four buttons on the hand controller are pressed, the LED in the center of the controller will
shine red; when the button is released, the LED will be green.
Also, when the LED starts to blink at a constant rate, its time
to change the batteries in the battery pack.
Using the R.A. and Dec. Reversal Switches
On the side of the hand controller, there are two reversal
switches, one for the R.A. axis, and one for the Dec. axis.
When these switches are flipped to the “REV” setting, the
function of the pushbuttons on the hand controller will be
reversed.The reversal switches allow you to orient the pushbuttons to the direction of the apparent movement of a guide
star in a guide scope for astrophotography.
Understanding the Setting Circles
The setting circles on an equatorial mount (Figure 12) enable
you to locate celestial objects by their “celestial coordinates”.
Every object resides in a specific location on the “celestial
sphere”. That location is denoted by two numbers: its right
ascension (R.A.) and declination (Dec.). In the same way,
every location on Earth can be described by its longitude and
latitude. Right ascension is similar to longitude on Ear th, and
declination is similar to latitude.The R.A. and Dec. values for
celestial objects can be found in any star atlas or star catalog.
The R.A. setting circle is scaled in hours, from 1 through 24,
with small marks in between representing 10-minute increments (there are 60 minutes in 1 hour of right ascension).The
lower set of numbers apply to viewing in the Northern
Hemisphere, while the numbers above them apply to viewing
in the Southern Hemisphere.
The Dec. setting circle is scaled in degrees, with each mark
representing 2° increments.Values of declination coordinates
range from +90° to -90°. The 0° mark indicates the celestial
equator.When the telescope is pointed nor th of the celestial
equator, values of the declination setting circle are positive;
when the telescope is pointed south of the celestial equator,
values of the declination setting circle are negative.
So, the coordinates for the Orion Nebula listed in a star atlas
will look like this:
R.A. 5h 35.4m Dec. –5° 27'
That’s 5 hours and 35.4 minutes in right ascension, and -5
degrees and 27 arc-minutes in declination (there are 60 arcminutes in 1 degree of declination).
Before you can use the setting circles to locate objects, the
mount must be accurately polar aligned, and the setting circles must be calibrated.
Calibrating the Declination Setting Circle
1. Loosen the Dec. lock lever and position the telescope as
accurately as possible in declination so it is parallel to the
R.A. axis as shown in Figure 7. Re-tighten the lock lever.
2. Loosen one of the thumbscrews on the Dec. setting circle,
this will allow the setting circle to rotate freely. Rotate the
Figure 12. The R.A. and Dec. setting circles.
Dec. setting circle
Dec. setting circle
thumbscrew (2)
Dec. indicator arrow
R.A. setting circle
R.A. indicator arrow
R.A. setting circle
thumbscrew
(2)
Dec. setting circle until the pointer reads exactly 90°.Re-
tighten the setting circle thumbscrew.
Calibrating the Right Ascension Setting Circle
1. Identify a bright star in the sky near the celestial equator
(declination = 0°) and look up its coordinates in a star
atlas.
2. Loosen the R.A. and Dec. lock levers on the equatorial
mount, so the telescope optical tube can move freely.
3. Point the telescope at the bright star whose coordinates
you know. Lock the R.A. and Dec. lock levers. Center the
star in the telescope’s field of view with the hand controller.
4. Loosen one of the R.A. setting circle thumbscrews (see
Figure 12) this will allow the setting circle to rotate freely.
Rotate the setting circle until the R.A. pointer arrow indicates the R.A. coordinate listed in the star atlas for the
object. Re-tighten the setting circle thumbscrew.
Finding Objects With the Setting Circles
Now that both setting circles are calibrated, look up in a star
atlas the coordinates of an object you wish to view.
1. Loosen the Dec. lock lever and rotate the telescope until
the declination value from the star atlas matches the reading on the Dec.setting circle.Remember that values of the
Dec.setting circle are positive when the telescope is pointing north of the celestial equator (Dec. = 0°), and negative
when the telescope is pointing south of the celestial equator.Retighten the lock lever.
2. Loosen the R.A. lock lever and rotate the telescope until
the right ascension value from the star atlas matches the
reading on the R.A. setting circle. Remember to use the
lower set of numbers on the R.A. setting circle. Retighten
the lock lever.
Most setting circles are not accurate enough to put an object
dead-center in the telescope’s eyepiece, but they should place
the object somewhere within the field of view of the finder
scope, assuming the equatorial mount is accurately polar
aligned.Use the hand controller to center the object in the finder scope, and it should appear in the telescope’s field of view.
The setting circles should be re-calibrated every time you wish
to locate a new object. Do so by calibrating the setting circles
for the centered object before mo ving on to the next one.
Confused About Pointing the Telescope?
Beginners occasionally experience some confusion about
how to point the telescope overhead or in other directions.In
Figure 1 the telescope is pointed north as it would be during
polar alignment. The counterweight shaft is oriented downward. But it will not look like that when the telescope is pointed in other directions.Let’s say you want to view an object that
is directly overhead, at the zenith.How do you do it?
DO NOT make any adjustment to the latitude adjustment Lbolts.That will spoil the mount’s polar alignment. Remember,
once the mount is polar aligned, the telescope should be
moved only on the R.A. and Dec. axes. To point the scope
overhead, first loosen the R.A.lock lever and rotate the telescope on the right ascension axis until the counterweight shaft
is horizontal (parallel to the ground). Then loosen the Dec.
lock lever and rotate the telescope until it is pointing straight
overhead. The counterweight shaft is still horizontal. Then
retighten both lock levers.
What if you need to aim the telescope directly north, but at an
object that is nearer to the horizon than Polaris? You can’t do
it with the counterweights down as pictured in Figure 1.Again,
you have to rotate the scope in right ascension so that the
counterweight shaft is positioned horizontally.Then rotate the
scope in declination so it points to where you want it near the
horizon.
To point the telescope directly south, the counterweight shaft
should again be horizontal.Then you simply rotate the scope
on the declination axis until it points in the south direction.
To point the telescope to the east or west, or in other directions, you rotate the telescope on its right ascension and declination axes.Depending on the altitude of the object you want
to observe, the counterweight shaft will be oriented somewhere between vertical and horizontal.
Figure 13 illustrates how the telescope will look when pointed
at the four cardinal directions:north, south, east and west.
The key things to remember when pointing the telescope are
that a) you only move it in right ascension and declination, not
in azimuth or latitude (altitude), and b) the counterweight and
shaft will not always appear as it does in Figure 1. In fact it
almost never will!
11
Figure 13a-d. These illustrations show the telescope pointed in the four cardinal directions. (a) nor th, (b) south, (c) east, (d) west. Note
that the tripod and mount have not been moved;only the telescope has been moved on the its R.A. and Dec. axes.
a. b. c. d.
7. Collimating
(Aligning The Mirrors)
Collimating is the process of adjusting the mirrors so they are
aligned with one another.Y our telescope’s optics were aligned
at the factory, and should not need much adjustment unless
the telescope is handled roughly. Accurate mirror alignment is
important to ensure the peak performance of your telescope,
so it should be checked regularly. Collimating is relatively easy
to do and can be done in daylight.
To check collimation, remove the eyepiece and look down the
focuser drawtube. You should see the secondary mirror centered in the drawtube, as well as the reflection of the primary
mirror centered in the secondary mirror, and the reflection of
the secondary mirror (and your eye) centered in the reflection
of the primary mirror, as in Figure 14a. If anything is off-center, as in Figure 14b, proceed with the following collimating
procedure.
Note About the 2" Focuser
The Atlas 8 EQ’s 2" focuser can be collimated by 3 pairs of
push-pull screws located on the ring at the base of the focuser
(Figure 4). The focuser was collimated at the factory and
should never need to be adjusted.Focuser collimating is only
required under very rare circumstances but has been made
available for this telescope should such a need arise.
The Collimation Cap and Mirror Center Mark
Your Atlas 8 EQ comes with a collimation cap.This is a simple
cap that fits on the focuser drawtube lik e a dust cap, but has a
hole in the center and a silver bottom.This helps center your
eye so that collimating is easy to perform.Figures 14b through
14e assume you have the collimation cap in place.
In addition to the collimation cap, the primary mirror is marked
with a circle at its exact center. This “center mark” allows you
to achieve a precise collimation of the primary mirror; you
don’t have to guess where the center of the mirror is.Y ou simply adjust the mirror position (described below) until the reflection of the hole in the collimation cap is centered in the ring.
The center mark is also required for best results when using
other collimating devices, such as Orion’s LaserMate Laser
Collimator, obviating the need to remove the primary mirror
and mark it yourself.
Note:The center ring sticker need not ever be removed
from the primary mirror. Because it lies directly in the
shadow of the secondary mirror, its presence in no way
adversely affects the optical performance of the telescope or the image quality. That might seem counterintuitive, but its true!
Aligning the Secondary Mirror
With the collimation cap in place, look through the hole in the
cap at the secondary (diagonal) mirror. Ignore the reflections
for the time being.The secondar y mirror itself should be centered in the focuser drawtube, in the direction parallel to the
length of the telescope. If it isn’t, as in Figure 14b, it must be
adjusted.This adjustment will rarely, if ever need to be done.
It helps to adjust the secondary mirror in a brightly lit room
with the telescope pointed towards a bright surface, such as
white paper or wall. Also placing a piece of white paper in the
telescope tube opposite the focuser (in other words, on the
other side of the secondary mirror) will also be helpful in collimating the secondary mirror. Using a 2mm hex wrench,
loosen the three small alignment set screws in the center hub
of the 4-vaned spider several turns. Now keep the mirror’s
holder stationary (be careful not to touch the surface of the
mirrors), while turning the center screw with a Phillips head
screwdriver (See Figure 15).Turning the screw clockwise will
move the secondary mirror toward the front opening of the
optical tube, while turning the screw counter-clockwise will
move the secondary mirror toward the primary mirror.
Note:When making these adjustments, be careful not to
stress the spider vanes or they may bend.
When the secondary mirror is centered in the focuser drawtube, rotate the secondary mirror holder until the reflection of
the primary mirror is as centered in the secondar y mirror as
possible.It may not be perfectly centered, but that is OK.Now
tighten the three small alignment screws equally to secure the
secondary mirror in that position.This adjustment will rarely, if
ever need to be done.
If the entire primary mirror reflection is not visible in the secondary mirror, as in Figure 14c; you will need to adjust the tilt
12
Figure 14. Collimating the optics.(a) When the mirrors are properly aligned, the view down
the focuser drawtube should look like this (b) With the collimation cap in place, if the optics are
out of alignment, the view might look something like this.(c) Here, the secondary mirror is
centered under the focuser, but it needs to be adjusted (tilted) so that the entire primary mirror
is visible.(d) The secondary mirror is correctly aligned, but the primary mirror still needs
adjustment.When the primary mirror is correctly aligned, the “dot”will be centered, as in (e).
a.
b. c. d. e.
13
of the secondary mirror.This is done by alternately loosening
one of the three alignment set screws while tightening the
other two, as depicted in Figure 16.The goal is to center the
primary mirror reflection in the secondar y mirror, as in Figure
14d. Don’t worry that the reflection of the secondar y mirror
(the smallest circle, with the collimation cap “dot” in the center) is off-center.You will fix that in the next step.
Adjusting the Primary Mirror
The final adjustment is made to the primary mirror.It will need
adjustment if, as in Figure 14d, the secondary mirror is centered under the focuser and the reflection of the primary mirror is centered in the secondary mirror, but the small reflection
of the secondary mirror (with the “dot” of the collimation cap)
is off-center.
The tilt of the primary mirror is adjusted with three springloaded collimation thumbscrews on the back end of the optical tube (bottom of the primary mirror cell); these are the larger thumbscrews. The other three smaller thumbscrews lock
the mirror’s position in place; these thumbscrews must be
loosened before any collimation adjustments can be made to
the primary mirror.
To start, turn the smaller thumbscrews that lock the primary
mirror in place a few turns each (Figure 17).Use a screwdriver in the slots, if necessary.
Now, try tightening or loosening one of the larger collimation
thumbscrews with your fingers (Figure 18). Look into the
focuser and see if the secondary mirror reflection has moved
closer to the center of the primary. You can tell this easily with
the collimation cap and mirror center mark by simply watching
to see if the “dot”of the collimation cap is moving closer or further away from the “ring” on the center of the pr imary mirror
mark.When you have the dot centered as much as is possible
in the ring, your primary mirror is collimated.The view through
the collimation cap should resemble Figure 15e. Re-tighten
the locking thumbscrews.
A simple star test will tell you whether the optics are accurately collimated.
Figure 15. To center the secondary mirror under the focuser,
hold the secondary mirror holder in place with one hand while
adjusting the center bolt with a Phillips screwdriver.Do not touch the
mirror’s surface!
Figure 16. Adjust the tilt of the secondary mirror by loosening or
tightening the three alignment set screws with a 2m m hex key.
Figure 17. The three small thumbscrews that lock the primary
mirror in place must first be loosened before any adjustments can
be made.
Figure 18. The tilt of the primary mirror is adjusted by turning
one or more of the three larger thumbscrews.
14
Star-Testing the Telescope
When it is dark, point the telescope at a bright star and accurately center it in the eyepiece’s field-of-view.Slowly defocus
the image with the focusing knob.If the telescope is correctly
collimated, the expanding disk should be a perfect circle
(Figure 19). If the image is unsymmetrical, the scope is out of
collimation. The dark shadow cast by the secondary mirror
should appear in the very center of the out-of-focus circle, like
the hole in a doughnut.If the “hole”appears off-center, the telescope is out of collimation.
If you try the star test and the bright star you have selected is
not accurately centered in the eyepiece, then the optics will
always appear out of collimation, even though they may be
perfectly aligned.It is critical to keep the star centered, so over
time you will need to make slight corrections to the telescope’s
position in order to account for the sky’s apparent motion.
8. Astronomical Observing
For many users, the Atlas 8 EQ telescope will be a major leap
into the world of amateur astronomy.This section is intended
to get you ready for your voyages through the night sky.
Observing Tips
A. Site Selection
Pick a location awa y from street lights and bright yard lighting.
Avoid viewing over rooftops and chimneys, as the y often have
warm air currents rising from them, which distort the image
seen in the eyepiece. Similarly, you should not observe
through an open window from indoors. Better yet, choose a
site out-of-town, away from any “light pollution”.You’ll be
stunned at how many more stars you’ll see! Most importantly,
make sure that any chosen site has a clear view of a large
portion of the sky.
B. Seeing and Transparency
Atmospheric conditions play a huge part in quality of viewing.
In conditions of good “seeing”, star twinkling is minimal and
objects appear steady in the eyepiece. Seeing is best overhead, worst at the horizon. Also, seeing generally gets better
after midnight, when much of the heat absorbed by the Earth
during the day has radiated off into space.Typically, seeing
conditions will be better at sites that have an altitude over
about 3000 feet. Altitude helps because it decreases the
amount of distortion causing atmosphere you are looking
through.
A good way to judge if the seeing is good or not is to look at
bright stars about 40° above the horizon.If the stars appear to
“twinkle”, the atmosphere is significantly distorting the incoming light, and views at high magnifications will not appear
sharp. If the stars appear steady and do not twinkle, seeing
conditions are probably good and higher magnifications will
be possible.Also, seeing conditions are typically poor during
the day. This is because the heat from the Sun war ms the air
and causes turbulence.
Good “transparency” is especially important for observing
faint objects. It simply means the air is free of moisture,
smoke, and dust. All tend to scatter light, which reduces an
object’s brightness.
One good way to tell if conditions are good is by how many
stars you can see with your naked e ye .If you cannot see stars
of magnitude 3.5 or dimmer then conditions are poor. Magnitude is a measure of how bright a star is, the brighter a star is,
the lower its magnitude will be. A good star to remember for
this is Megrez (mag. 3.4), which is the star in the “Big Dipper”
connecting the handle to the “dipper”. If you cannot see
Megrez, then you have fog, haze, clouds, smog, light pollution
or other conditions that are hindering your viewing (See
Figure 20).
C. Cooling the Telescope
All optical instruments need time to reach “thermal equilibrium” to achieve maximum stability of the lenses and mirrors,
which is essential for peak performance.When moved from a
warm indoor location outside to cooler air (or vice-versa), a
telescope needs time to cool to the outdoor temperature.The
bigger the instrument and the larger the temperature change,
the more time will be needed.
Allow at least 30 minutes for your Atlas 8 EQ to equilibrate. If
the scope has more than a 40° temperature adjustment, allow
Figure 20. Megrez connects the Big Dipper’s handle to it's
“pan”. It is a good guide to how conditions are. If you can not see
Megrez (a 3.4 mag star) then conditions are poor.
Figure 19. A star test will determine if a telescope’s optics are
properly collimated. An unfocused view of a bright star through the
eyepiece should appear as illustrated on right if optics are perfectly
collimated. If circle is unsymmetrical, as in illustration on left, scope
needs collimation.
Out of collimation Collimated
1.9
4.9
2.4
1.9
2.4
1.7
3.4
2.5
15
an hour or more. In the winter, storing the telescope outdoors
in a shed or garage greatly reduces the amount of time needed for the optics to stabilize.It also is a good idea to keep the
scope covered until the Sun sets so the tube does not heat
greatly above the temperature of the outside air.
Youc an attach a small fan to the Atlas 8 EQ to make cooling
the tube faster. On the bottom of the mirror cell there are four
holes (M4x.7 thread) where a fan can be mounted.
D. Let Your Eyes Dark-Adapt
Do not expect to go from a lighted house into the darkness of
the outdoors at night and immediately see faint nebulas,
galaxies, and star clusters- or even very many stars, for that
matter. Your eyes take about 30 minutes to reach perhaps
80% of their full dark-adapted sensitivity. Many observers
notice improvements after several hours of total darkness. As
your eyes become dark-adapted, more stars will glimmer into
view and you will be able to see fainter details in objects you
view in your telescope.Exposing your eyes to very bright daylight for extended periods of time can adversely affect your
night vision for days.So give yourself at least a little while to
get used to the dark before you begin observing.
To see what you are doing in the darkness, use a red-filtered
flashlight rather than a white light. Red light does not spoil
your eyes’ dark adaptation like white light does. A flashlight
with a red LED light is ideal, or you can cover the front of a
regular incandescent flashlight with red cellophane or paper.
Beware, too, that nearby porch and streetlights and automobile headlights will spoil your night vision.
Eyepiece Selection
By using eyepieces of varying focal lengths, it is possible to
attain many magnifications with the Atlas 8 EQ.The telescope
comes with two high-quality Sirius Plössl eyepieces:a 25mm,
which gives a magnification of 40x, and a 10mm, which gives
a magnification of 100x. Other eyepieces can be used to
achieve higher or lower powers. It is quite common for an
observer to own five or more eyepieces to access a wide
range of magnifications.This allows the observer to choose
the best eyepiece to use depending on the object being
viewed.At least to begin with, the two supplied eyepieces will
suffice nicely.
Whatever you choose to view, always start by inserting your
lowest power (longest focal length) eyepiece to locate and
center the object. Low magnification yields a wide field of
view, which shows a larger area of sky in the eyepiece.This
makes acquiring and centering an object much easier.If you
try to find and center objects with high power (narrow field of
view), it’s like trying to find a needle in a haystack!
Once you’ve centered the object in the eyepiece, you can
switch to higher magnification (shorter focal length eyepiece),
if you wish. This is especially recommended for small and
bright objects, like planets and double stars.The Moon also
takes higher magnifications well.
Deep-sky objects, however, typically look better at medium or
low magnifications.This is because many of them are quite
faint, yet have some extent (apparent width). Deep-sky
objects will often disappear at higher magnifications, since
greater magnification inherently yields dimmer images.This is
not the case for all deep-sky objects, however. Many galaxies
are quite small, yet are somewhat bright, so higher power ma y
show more detail.
The best rule of thumb with eyepiece selection is to start with
a low power, wide field, and then work your way up in magnification. If the object looks better, try an even higher magnification. If the object looks worse, then back off the magnification
a little by using a lower power eyepiece.
What to Expect
So what will you see with your telescope? You should be able
to see bands on Jupiter, the rings of Saturn, craters on the
moon, the waxing and waning of Venus, and hundreds of deep
sky objects. Do not expect to see as much color as you in
NASA photos, since those are taken with long-exposure cameras and have “false color” added. Our eyes are not sensitive
enough to see color in deep-sky objects except in a fe w of the
brightest ones.
Remember that you are seeing these objects using your own
telescope with your own eyes! The object you see in your e y epiece is in real-time, and not some conveniently provided
image from an expensive space probe. Each session with
your telescope will be a learning experience. Each time you
work with your telescope it will get easier to use, and stellar
objects will become easier to find.Take it from us, there is big
difference between looking at a well-made full-color NASA
image of a deep-sky object in a lit room during the daytime,
and seeing that same object in your telescope at night. One
can merely be a pretty image someone gave to you.The other
is an experience you will never forget!
A. The Moon
With is rocky and cratered surface, the moon is one of the
most interesting and easy subjects for your scope.The best
time to view it is during its partial phases when shadows fall
on the craters and canyon walls to give its features definition.
While the full moon may look like a tempting target, it is actually the worst time for viewing! The light of a full moon is too
bright and lacks any decent surface definition.
Use an optional Moon filter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepiece from
the focuser (you must first remove the eyepiece from the
focuser to attach the filter).You’ll find the Moon filter improves
viewing comfort, and helps bring out the subtle features if the
lunar surface.
B. The Sun
You can change your nighttime telescope into a daytime Sun
viewer by installing an optional full-aperture solar filter over
the front opening of a Atlas 8 EQ. The pr imary attraction is
sunspots, which change shape, appearance, and location
daily. Sunspots are directly related to magnetic activity in the
Sun. Many observers like to make drawings of sunspots to
monitor how the Sun is changing from day to day.
16
Important Note: Do not look at the Sun with any optical
instrument without a professionally made solar filter, or
permanent eye damage could result. Also, be sure to
cover the finder scope, or better yet, remove it altogether.
C. The Planets
The planets don’t stay put like the stars, so to find them you
should refer to Sky Calendar at our website telescope.com, or
to charts published monthly in Astronomy, Sky & Telescope,
or other astronomy magazines. Venus, Mars, Jupiter, and
Saturn are the brightest objects in the sky after the Sun and
the Moon.Your Atlas 8 EQ is capable of showing you these
planets in some detail. Other planets may be visible but will
likely appear starlike. Because planets are quite small in
apparent size, optional higher power eyepieces are recommended and often needed for detailed observations. Not all
the planets are generally visible at any one time.
JUPITER The largest planet, Jupiter, is a great subject for
observation. You can see the disk of the giant planet and
watch the ever-changing positions of its four largest moons—
Io, Callisto, Europa, and Ganymede. Higher power eyepieces
should bring out the cloud bands on the planet’s disk.
SATURN The ringed planet is a breathtaking sight when it is
well positioned.The tilt angle of the r ings varies over a period
of many years; sometimes they are seen edge-on, while at
other times they are broadside and look like giant “ears” on
each side of Saturn’s disk. A steady atmosphere (good seeing) is necessary for a good view. You will probably see a
bright “star” close by, which is Saturn’s brightest moon, Titan.
VENUS At its brightest, Venus is the most luminous object in
the sky, excluding the Sun and the Moon. It is so bright that
sometimes it is visible to the naked eye during full daylight!
Ironically, Venus appears as a thin crescent, not a full disk,
when at its peak brightness.Because it is so close to the Sun,
it never wanders too far from the morning or evening horizon.
No surface markings can be seen on Venus, which is always
shrouded in dense clouds.
MARS The Red Planet makes its closest approach to Earth
every two years. During close approaches you’ll see a red
disk, and may be able to see the polar ice cap.To see surface
detail on Mars, you will need a high power eyepiece and very
steady air!
D. The Stars
Stars will appear like twinkling points of light. Even powerful
telescopes cannot magnify stars to appear as more than a
point of light! You can, however, enjoy the different colors of
the stars and locate many pretty double and multiple stars.
The famous “Double-Double” in the constellation Lyra and the
gorgeous two-color double star Albireo in Cygnus are
fav orites.Defocusing a star slightly can help bring out its color.
Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinating
deep-sky objects, including gaseous nebulas, open and globular star clusters, and a variety of different types of galaxies.
Most deep-sky objects are very faint, so it is important that
you find an observing site well away from light pollution.Take
plenty of time to let your eyes adjust to the darkness.Do not
expect these subjects to appear like the photographs you see
in books and magazines; most will look like dim gray
smudges. But as you become more experienced and your
observing skills get sharper, you will be able to ferret out more
and more subtle details and structure.
How to Find Deep-sky Objects: Starhopping
Starhopping, as it is called by astronomers, is perhaps the
simplest way to hunt down objects to view in the night sky. It
entails first pointing the telescope at a star close to the object
you wish to observe, and then progressing to other stars closer and closer to the object until it is in the field of view of the
eyepiece. It is a very intuitive technique that has been
employed for hundreds of years by professional and amateur
astronomers alike. Keep in mind, as with any new task, that
starhopping may seem challenging at first, but will become
easier over time and with practice.
To starhop, only a minimal amount of additional equipment is
necessary. A star chart or atlas that shows stars to at least
magnitude 5 is required. Select one that shows the positions
of many deep-sky objects, so you will have a lot of options to
choose from.If you do not know the positions of the constellations in the night sky, you will need to get a planisphere to
identify them.
Start by choosing bright objects to view.The brightness of an
object is measured by its visual magnitude; the brighter an
Figure 21. Starhopping is a good way to locate hard-to-find
objects. Refer to a star chart to map a route to the object that uses
bright stars as guideposts. Center the first star you’ve chosen in the
finder scope and telescope eyepiece (1).Now move the scope
carefully in the direction of the next bright star (2), until it is
centered. Repeat (3 and 4). The last hop (5) should place the
desired object in the eyepiece.
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object, the lower its magnitude.Choose an object with a visual magnitude of 9 or lower. Many beginners start with the
Messier objects, which represent some of the best and brightest deep-sky objects, first catalogued about 200 years ago by
the French astronomer Charles Messier.
Determine in which constellation the object lies. Now, find the
constellation in the sky. If you do not recognize the constellations on sight, consult a planisphere.The planisphere gives an
all-sky view and shows which constellations are visible on a
given night at a given time.
Now, look at your star chart and find the brightest star in the
constellation that is near the object you are trying to find.
Using the finder scope, point the telescope at this star and
center it on the crosshairs. Next, look again at the star chart
and find another suitably bright star near the bright star currently centered in the finder.Keep in mind that the field of view
of the finder scope is approximately 7°, so you should choose
another star that is no more that 7° from the first star, if possible.Move the telescope slightly , until the telescope is centered
on the new star.
Continue using stars as guideposts in this way until you are at
the approximate position of the object you are trying to find
(Figure 21). Look in the telescope’s eyepiece, and the object
should be somewhere within the field of view.If it’s not, sw eep
the telescope carefully around the immediate vicinity until the
object is found.
If you have trouble finding the object, start the starhop again
from the brightest star near the object you wish to view.This
time, be sure the stars indicated on the star chart are in fact
the stars you are centering in the eyepiece. Remember, the
finder scope (and main telescope eyepiece, for that matter)
gives an inverted image, so you must keep this in mind when
starhopping from star to star.
9. Astrophotography
When coupled to a 35mm single-lens reflex camera, the Atlas
8 EQ becomes a telephoto lens.To attach a camera, you need
only a T-ring for your specific camera model and the included
camera adapter. First you must attach the included camera
adapter to the Atlas 8 EQ’s focuser. To do this, remove the
1.25” and 2" eyepiece adapters from the focuser drawtube
(Figure 22a).Then screw the camera adapter into the focuser
drawtube (Figure 22b).Now attach the T-Ring to your camera
and thread it onto the camera adapter (Figure 22c).
Use the camera’s vie wfinder to frame the picture.Use the telescope’s focuser to focus the image.You may want to consider
using a remote shutter release instead of the shutter release
on the camera; touching the camera can vibrate the system
and blur the resulting photographic image on the film.Use the
focus lock knob on the f ocuser to fix the f ocus when the image
is sharp.
Several different types of astrophotography can be successfully attempted with the Atlas 8 EQ.
Moon Photography
This is perhaps the simplest form of astrophotography. Point
the telescope toward the Moon, and center it within the camera’s vie wfinder .Focus the image with the telescope’s f ocuser.
Try several exposure times, all less than 1 second, depending
on the phase of the moon and the ISO (film speed) of the film
being used. A remote shutter release is recommended, as
touching the camera’s shutter release can vibrate the camera
enough to ruin the exposure.
Planetary Photography
Once basic Moon photography has been mastered, it’s time to
get images of the planets.This type of astrophotography also
works to get highly magnified shots of the Moon.In addition to
the T-ring, you will need a Universal 1.25" Camera Adapter.
The equatorial mount must be accurately polar aligned, too.
As before, connect the T-r ing to your camera. Before connecting the universal camera adapter to the T-r ing, an eyepiece
must be inserted and locked into the body of the universal
camera adapter.Start by using a medium-low power eyepiece
(about 25mm); you can increase the magnification later with a
high-power eyepiece. Then connect the entire camera
adapter, with eyepiece inside, to the T-ring. Insert the whole
system into the focuser’s 1.25" adapter and secure firmly with
the thumbscrew.
Aim the telescope at the planet (or Moon) you wish to shoot.
The image will be highly magnified, so you may need to use
the finder scope to center it within the camera’s viewfinder.
Turn the motor drive on.Adjust the telescope’s f ocuser so that
the image appears sharp in the camera’s viewfinder .The cam-
Figure 22a. First remove both the 1.25"
and 2" adapters as shown
Figure 22b. Thread the camera adapter
into the focuser drawtube
Figure 22c. The SkyView Pro 8 EQ with
35mm SLR camera attached
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era’s shutter is now ready to be opened. A remote shutter
release must be used or the image will be blurred beyond
recognition. Try exposure times between 1 and 10 seconds,
depending upon the brightness of the planet to be photographed and the ISO of the film being used.
“Piggyback Photography”
The Moon and planets are interesting targets for the budding
astrophotographer, but what next? Literally thousands of
deep-sky objects can be captured on film with a type of
astrophotography called “piggybacking”.The basic idea is that
the camera with its own camera lens attached rides on top of
the main telescope. The telescope and camera both move
with the rotation of the Earth when the mount is polar aligned
and the motor drive is engaged.This allows for a long exposure through the camera without having the object or background stars blurred. An illuminated reticle eyepiece will also
be needed. The T-ring and camera adapter are not needed,
since the camera is exposing through its own lens.Any camera lens with a focal length between 35mm and 400mm is
appropriate.
On the top of one of the tube rings is a piggyback camera
adapter.This is the black knob with the threaded shaft protruding through it. The tube ring with the piggyback adapter
should be closest to the open end of the telescope tube.
Remove the tube rings from the equatorial mount and swap
their position if necessary. Now, connect the camera to the
piggyback adapter.There should be a 1/4"-20 mounting hole
in the bottom of the camera’s body. Thread the protruding
shaft of the piggyback adapter into the 1/4"-20 mounting hole
in the camera a few turns.Position the camera so it is parallel
with the telescope tube and turn the knurled black knob of the
piggyback adapter counter-clockwise until the camera is
locked into position.
Aim the telescope at a deep-sky object. It should be a fairly
large deep-sky object, as the camera lens will likely have a
wide field of view. Check to make sure that the object is also
centered in the camera’s viewfinder. Tur n the motor drive on.
Now, look into the telescope’s eyepiece and center the brightest star within the field of view. Remove the eyepiece and
insert the illuminated reticle eyepiece into the focuser drawtube.Turn the eyepiece’s illuminator on (dimly!). Recenter the
bright star (guide star) on the crosshairs of the reticle eyepiece. Check again to make sure that the object to be photographed is still centered within the camera’s field of view.If it
is not, recenter it by repositioning the camera on the piggyback adapter, or by moving the main telescope. If you move
the main telescope, then you will need to recenter another
guide star on the illuminated eyepiece’s crosshairs. Once the
object is centered in the camera and a guide star is centered
in the reticle eyepiece, you’re ready to shoot.
Deep-sky objects are quite faint, and typically require exposures on the order of 10 minutes.To hold the camera’s shutter
open this long, you will need a lock shutter release cable.Set
the camera’s shutter to the “B” (bulb) setting. Depress the
locking shutter release cable and lock it. You are now exposing your first deep-sky object.
While exposing through the camera lens, you will need to
monitor the accuracy of the mount’s tracking by looking
through the illuminated reticle eyepiece in the main telescope.
If the guide star drifts from its initial position, then use the
hand controller (at the 2x rate) of the motor drive to “move” the
guide star back to the center of the crosshairs. Any drifting
along the Dec. axis is a result of improper polar alignment, so
if the guide star drifts greatly in Dec., the mount may need to
be polar aligned more accurately.
When the exposure is complete, unlock the shutter release
cable and close the camera’s shutter.
Astrophotography can be enjoyable and rewarding, as well as
frustrating and time-consuming. Star t slowly and consult outside resources, such as books and magazines, for more
details about astrophotography. Remember ... have fun!
10. Care and Maintenance
If you give your telescope reasonable care, it will last a lifetime. Store it in a clean, dry, dust-free place, safe from rapid
changes in temperature and humidity. Do not store the telescope outdoors, although storage in a garage or shed is OK.
Small components like eyepieces and other accessories
should be kept in a protective box or storage case. Keep the
dust cover on the front of the telescope when not in use.
Your Atlas 8 EQ requires very little mechanical maintenance.
The optical tube is steel and has a smooth painted finish that
is fairly scratch-resistant.If a scratch does appear on the tube,
it will not harm the telescope. Smudges on the tube can be
wiped off with a soft cloth and a household cleaner such as
Windex or Formula 409.
Cleaning Lenses
Any quality optical lens cleaning tissue and optical lens cleaning fluid specifically designed for multi-coated optics can be
used to clean the exposed lenses of your eyepieces or finder
scope. Never use regular glass cleaner or cleaning fluid
designed for eyeglasses .Before cleaning with fluid and tissue,
however, blow any loose particles off the lens with a blower
bulb or compressed air.Then apply some cleaning fluid to a
tissue, never directly on the optics. Wipe the lens gently in a
circular motion, then remove any e xcess fluid with a fresh lens
tissue. Oily fingerpr ints and smudges may be removed using
this method. Use caution; rubbing too hard may scratch the
lens.On larger lenses, clean only a small area at a time, using
a fresh lens tissue on each area. Never reuse tissues.
Cleaning Mirrors
You should not have to clean the telescope’s mirrors very
often; normally once every year or so. Covering the telescope
with the dust cover when it is not in use will prevent dust from
accumulating on the mirrors. Improper cleaning can scratch
mirror coatings, so the fewer times you have to clean the mirrors, the better.Small specks of dust or flecks of paint have
virtually no effect on the visual performance of the telescope.
The large primary mirror and the elliptical secondar y mirror of
your telescope are front-surface aluminized and over-coated
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with hard silicon dioxide, which prevents the aluminum from
oxidizing.These coatings normally last through many years of
use before requiring re-coating (which is easily done).
To clean the secondary mirror, first remove it from the telescope.Do this by holding the secondary mirror holder stationary while completely unthreading the center Phillips-head
screw. Be careful, there is a spring between the secondar y
mirror holder and the Philips-head screw; be sure that it will
not fall into the optical tube and hit the primary mirror.Handle
the mirror by its holder; do not touch the mirror surface. Then
follow the same procedure described below for cleaning the
primary mirror.You do not need to remove the secondary mirror from its holder when cleaning.
To clean the primary mirror, carefully remove the mirror cell
from the telescope.To do this means you must remove the six
screws on the side of the tube near the mirror cell.You do not
need to remove the collimation screws on the bottom of the
mirror cell. Remove the mirror cell from the tube. You will
notice the primary mirror is held down with three clips held by
two screws each.Loosen the screws and remove the clips.
You may now remove the mirror from the mirror cell. Do not
touch the surface of the mirror with your fingers.Lift the mirror
carefully by the edges.Set the mirror on a clean soft towel. Fill
a clean sink free of abrasive cleanser, with room-temperature
water, a few drops of liquid dishwashing detergent, and if possible, a capful of rubbing alcohol. Submerge the mirror (aluminized face up) in the water and let it soak for a few minutes
(or hours if it’s a very dirty mirror).Wipe the mirror under water
with clean cotton balls, using extremely light pressure and
stroking in straight line across the mirror.Use one ball for each
wipe across the mirror.Then rinse the mirror under a stream
of lukewarm water. Any particles on the surface can be
swabbed gently with a series of cotton balls, each used just
one time. Dry the mirror in a stream of air (a “blowe r bulb”
works great), or remove any stray drops of water with the corner of a paper towel.Water will run off a clean surface. Cover
the mirror surface with Kleenex, and leave the mirror in a
warm area until it is completely dry before reassembling the
telescope.
11. Specifications
Primary mirror diameter : 203mm
Primary mirror coating: Aluminized, SiO2overcoat
Focal length: 1000mm
Focal ratio: f/4.7
Secondary mirror axis: 58mm minor axis
Secondary mirror holder: Four-vaned spider
Eyepiece: 25mm and 10mm Sirius Plössls, fully coated,
1.25"
Magnification: 40x (with 25mm) and 100x (10mm)
Finder scope: 6x30 achromatic, 7° field of view
Focuser: Rack and pinion, push-pull tilt adjustment for
collimating, accepts 2" and 1.25" eyepieces
Camera adapter: couples 35mm SLR camera T-Ring to
focuser
Mount: Atlas, German equator ial
Tripod: Steel
Tripod support tray: Aluminum, provides additional stability,
holds five 1.25" eyepeices and two 2" eyepieces
Weight: 98 lbs.
Counterweights: Quantity 2, 11 lbs. each
Setting circles: R.A. scaled in 10 min. increments, Dec.
scaled in 2° increments for N or S hemisphere
Polar axis latitude adjustment:10° to 65°
Polar axis finder scope:Included
Motor drives: Dual-axis, internally housed
Power requirements: 12V DC, tip positive
Battery type: Eight D-cells
Operation: Nor ther n or Souther n hemisphere
Guiding rates: Sidereal ±100% sidereal
Centering rates: ±8x sidereal, ±16x sidereal
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One-Year Limited Warranty
This Orion Atlas 8 EQ is warranted against defects in materials or workmanship for a period of
one year from the date of purchase.This warranty is for the benefit of the original retail purchaser only.During this warranty period Orion Telescopes & Binoculars will repair or replace, at
Orion’s option, any warranted instrument that proves to be defective, provided it is returned
postage paid to: Orion Warranty Repair, 89 Hangar Way, Watsonville, CA 95076. If the product
is not registered, proof of purchase (such as a copy of the original invoice) is required.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishan-
dled, or modified, nor does it apply to normal wear and tear.This warranty gives you specific
legal rights, and you may also ha ve other rights, which vary from state to state.For further warranty service information, contact: Customer Service Department, Orion Telescopes &
Binoculars, P.O.Box 1815, Santa Cruz, CA 95061; (800)676-1343.
Orion Telescopes & Binoculars
Post Office Box 1815, Santa Cruz, CA 95061
Customer Support Help Line (800)676-1343 • Day or Evening
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