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INSTRUCTION MANUAL
Orion®
SpaceProbe™ II 76mm
Equatorial Reflector
#10274
Providing Exceptional Consumer Optical Products Since 1975
All Rights Reserved. No part of this product instruction or any of its contents may be reproduced, copied,
modied or adapted, without the prior written consent of Orion Telescopes & Binoculars.
®
Copyright © 2017 Orion Telescopes & Binoculars
Customer Support:
www.OrionTelescopes.com/contactus
Corporate Offices:
89 Hangar Way, Watsonville CA 95076 – USA
IN 578 08/17
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Congratulations on your purchase of an Orion telescope. Your new SpaceProbe II 76mm Equatorial
Reector. is a terric starter instrument for exploring the exotic wonders of the night sky. Designed to
be lightweight and easy to use, it will provide many hours of enjoyment for the whole family.
If you have never owned a telescope before, we would like to welcome you to amateur astronomy. Take
some time to familiarize yourself with the night sky. Learn to recognize the patterns of stars in the major
constellations. With a little practice, a little patience, and a reasonably dark sky away from city lights, you’ll
nd your telescope to be a never-ending source of wonder, exploration, and relaxation.
These instructions will help you set up, properly use, and care for your telescope. Please read them over
thoroughly before getting started.
Table of Contents
1. Parts .......................................2
2. Assembly....................................2
3. Preparing the Telescope for Operation .............5
4. Understanding and Using the Equatorial Mount ......8
5. Astronomical Observing .......................12
6. Useful Optional Accessories ....................14
7. Aligning the Mirrors (Collimation) ................14
8. Telescope Care and Maintenance ................ 15
9. Specications ...............................16
WARNING: Never look directly at the Sun through
your telescope—even for an instant—without a
professionally made solar lter that completely
covers the front of the instrument, or permanent eye
damage could result. Young children should use this
telescope only with adult supervision.
1. Parts
Remove and identify all parts, using the list below and Figure 1
for reference.
Part Qty
A – Tripod legs 3
B – Hex-head tripod mounting bolts 3
C – Washers (5/8") 3
D – Wing nuts (large) 3
E – Leg lock thumbscrew 3
F – Accessory tray 1
G – Screws 3
H – Washers (3/8") 3
I – Wing nuts (small) 3
J – Equatorial mount 1
K – Azimuth lock knob (and washer) 1
L – Latitude adjustment bolt 1
M – Counterweight shaft 1
N – Counterweight lock knob 1
O – Counterweight 1
P – Slow-motion cables 2
Q – Mounting platform 1
R – Tube ring 1
S – Tube ring mounting hardware 6
T – Screwdriver tool 1
U – Optical tube assembly 1
V – Red dot nder scope 1
W – 25mm Kellner eyepiece 1
X – 10mm Kellner eyepiece 1
Y – Dust cover 1
Z – Allen wrench (not shown) 1
2. Assembly
Refer to Figures 1 and 2 and the parts list at left for identica-
tion of specic parts during assembly.
1. Attach the three aluminum tripod legs (A) to the mounting
platform (Q) (Figure 3a) with the three hinged leg braces
facing inward. Three hex-head bolts (B) each about 3" long,
with 5/8" washers (C) and wing nuts (D), are provided for
this purpose. Note that the bolts should be inserted from
the side of the leg that has the hex-shaped hole, so that
the bolt head seats in the hex-shaped hole (Figure 3b).
The washer then the wing nut are placed on the opposite
side on the exposed end of the bolt.
2. Attach a leg lock thumbscrew (E) to each leg as shown
(Figure 4). Extend the sliding inner portion of the adjust-
able-height tripod leg to the desired length for all three
legs. Lock in place by tightening the leg lock thumbscrews.
Do not over-tighten the leg lock thumbscrews or you may
damage the collar they are attached to.
3. Now stand the tripod upright, spreading the legs evenly
apart so the accessory tray can be positioned to attach to
the three leg braces.
4. Attach the accessory tray (F) to the leg brace supports
(Figure 5) with the three short screws (G), small (3/8")
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W
U
Y
Q
N
O
B
A
C
D
X
R
G/H/I
Figure 1.
V
P
F
E
The parts of the SpaceProbe II 76mm EQ telescope.
PL
M T
J K SV
W
R.A. Axis
J
M
L
N
O
A
R
U
P
X
Figure 2. The SpaceProbe II 76 EQ telescope fully assembled with key parts identied.
Dec. Axis
A
A
E
F
E
E
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Wingnut
Washer
Figure 3. a)
Attach the three tripod legs to the mount platform,
b) making sure the bolt’s hex-shaped head seats in the hex-shaped
recess of the tripod leg.
washers (H), and small wing nuts (I) provided. Place a
washer on the screw. Then place the accessory tray on
top of one of the leg braces so that the mounting screw
passes through the hole at one of the corners of the
accessory tray, and through the slot in the leg brace. Then
place another small washer on the screw and thread on
and tighten the wing nut. Repeat this procedure until the
tray is attached to all three leg braces.
The tripod is now fully assembled (Figure 6). Next you will
install the equatorial mount onto the tripod.
5. Locate the equatorial (EQ) mount (J) and place its base into
the hole in the center of the mounting platform (Q) (Figure
7a). Then secure it in place with the azimuth lock knob and
washer (K) (Figure 7b).
6. Thread the latitude adjustment bolt (L) into the threaded
socket (Figure 8) until it contacts metal inside the housing.
7. Next, thread the counterweight shaft (M) into the base of
the Declination axis of the mount (Figure 9).
8. Thread the counterweight lock knob (N) into the counterweight (O) a few turns.
9. To slide the counterweight onto the counterweight shaft,
rst remove the Philips screw and washer from the end of
the shaft. You can use the screwdriver tool (T) for this. Make
sure the counterweight lock knob (N) is loosened enough
so that the metal pin inside the counterweight is clear of
the shaft hole. Slide the counterweight about 2 inches from
the bottom of the counterweight shaft and secure it in place
with the lock knob (Figure 10). Then replace the washer
and screw at the end of the counterweight shaft.
10. Attach the slow motion cables (P) to the gear shafts as
shown in Figure 11. The longer cable should be attached
to the declination gear shaft; the shorter cable to the right
ascension gear shaft. Orient the cable so that the thumbscrew seats in the groove of the gear shaft, as shown in
Figure 12, then rmly tighten the thumbscrew. If there is
a small rubber ball on the end of the shaft, you will have
to remove it in order to attach the cable. Also note that,
depending on your preference, you can attach the cable to
either the left or right side of the right ascension gear shaft.
Now the mount is properly attached to the tripod and outtted
for use (Figure 13). Next, you’ll attach the tube ring and opti-
cal tube to the EQ mount.
11. To attach the tube ring (R), set the bottom of the ring into
the EQ head’s saddle and bolt it on with the two supplied
socket head bolts, washers, and wing nuts (S) as shown
in Figure 14. You can use the supplied Allen wrench (Z,
not shown in Fig. 1) to help tighten the bolt while holding
the wing nut. Do not overtighten!
12. Then lay the telescope optical tube (U) into the open tube
ring. Close the tube ring around the tube and tighten the
tube ring clamp knob. The telescope should now look like
Figure 15.
13. To attach the red dot nder scope (V) to the optical tube,
orient the nder scope as shown in Figure 16 and slide
the bracket foot into the nder scope base until it clicks.
Figure 4. Thread a leg lock thumbscrew onto each tripod leg as
shown, being careful not to overtighten.
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Accessory tray
Screw head
Washer
Washer
Wing nut
Leg
Figure 5. Attach the accessory tray to each of the tripod three
leg brace supports using the provided hardware.
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Figure 6.
(To remove the nder scope, press the small tab at the
back of the base and slide the bracket out.)
14. Insert the 25mm eyepiece (W) into the focuser and secure
it by lightly tightening the thumbscrew (Figure 17).
The telescope is now completely assembled! Before it can be
effectively used, however, there are a couple of things to do to
prepare the telescope for operation.
The fully assembled tripod.
Washer
Azimuth
a.
Figure 7. a) Install the equatorial mount onto the tripod mount
platform, then b) secure it from the underside with azimuth lock knob.
1. First, remove the dust cap (Y) from the front of the telescope.
2. With the 25mm eyepiece already in place from step 14
above, point the telescope at a well-dened land target
(e.g., the top of a telephone pole) that’s at least a quarter
mile away. Center the target in the eyepiece by turning the
slow-motion cables as needed to point the telescope. For
larger telescope movement, release the RA and Dec axis
lock knobs (Figure 19) and move the telescope tube by
hand to the approximate location, then retighten the lock
knobs and make ner pointing adjustments with the slow
motion cables.
Note: The image in the telescope will appear rotated, often
upside down. This is normal for reector telescopes and is
why reectors are not recommended for daytime terrestrial
viewing.
3. Now that a distant target is centered in the main telescope’s eyepiece, turn on the red dot nder scope by slid-
lock knob
b.
3. Preparing the Telescope
for Operation
Aligning and Using the Red Dot Finder Scope
The included red dot nder scope (Figure 18) makes pointing
your telescope almost as easy as pointing your nger! It’s a
non-magnifying aiming device that superimposes a tiny LED
red dot on the sky, showing exactly where the telescope is
pointed. It permits easy object targeting prior to observation in
the higher-power main telescope.
Before you can use the red dot nder scope, you must remove
the small plastic tab sticking out from the battery compartment (Figure 18). Doing so will allow the pre-installed 3V
CR-2032 button cell battery to make contact with the nder
scope’s electronic circuitry to power the nder’s red LED illuminator. The tab can then be discarded.
To use the red dot nder scope properly, it must be aligned
with the main telescope. This is easiest to do during daylight
hours, before observing at night. Follow this procedure:
Latitude adjustment
bolt
Figure 8. Screw in the latitude adjustment bolt.
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Lock knob
Figure 9. Thread the counter-
weight shaft into the declination
housing.
Figure 10. The
counterweight, installed.
ing the power switch to ON (refer to Figure 18). The “1”
position provides dim illumination while the “2” position
provides brighter illumination. Typically the dimmer setting
is used under dark skies and the brighter setting is used
under light-polluted skies or in daylight. Position your eye
at a comfortable distance from the rear of the unit. Look
through the rear of the nder scope with both eyes open
to see the illuminated red dot. The target object should
appear in the eld of view somewhere near the red dot.
4. You’ll want to center the target object on the red dot. To do
so, without moving the telescope, use the nder scope’s
vertical and horizontal adjustment knobs (shown in Figure
18) to position the red dot on the object.
5. When the red dot is centered on the distant object, check
to make sure the object is still centered in the telescope’s
eyepiece. If it isn’t, re-center it then adjust the finder
Thumbscrew
Slow-motion
cable
Groove
Gear shaft
Figure 12. Line up the slow-motion cable thumbscrew with the
groove in the gear shaft, then tighten.
scope’s alignment again. When the object is centered in
the telescope eyepiece and on the nder scope’s red dot,
the nder scope is properly aligned with the telescope.
The red dot nder scope’s alignment should be checked
before every observing session.
At the end of your observing session, be sure to slide the
power switch on the red dot nder scope to OFF to preserve
battery life.
R.A. slow-motion cable
Latitude
adjustment
bolt
Latitude lock
knob
Figure 11.
placement of the slow-motion cables.
The assembled equatorial mount, showing
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Dec. slow-motion
cable
Figure 13. The fully assembled equatorial mount and tripod.
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Tube ring (open)
Socket head
bolts
Saddle
a.
b.
Wing nut
Washer
c.
Figure 14. Installing the tube ring onto the equatorial mount. a) Place open ring in saddle. b) Insert socket head screws through aligned
holes in ring and saddle, then c) place a washer onto the screw followed by a wing nut. Then tighten wing nut.
Balancing the Telescope
In order for the telescope to move smoothly on its mechanical
axes, the optical tube must rst be balanced on the mount as
follows:
1. Keeping one hand on the telescope optical tube, loosen
the R.A. lock knob. Make sure the Dec. lock knob is locked,
for now. The telescope should now be able to rotate freely
about the R.A. axis. Rotate it until the counterweight shaft
is parallel to the ground, i.e., horizontal (Figure 20a).
2. Now loosen the counterweight lock knob and slide the
weight along the shaft until it exactly counterbalances the
telescope. That’s the point at which the shaft remains horizontal even when you let go of the telescope with both
hands.
3. Retighten the counterweight lock knob. The telescope is
now balanced on the R.A. axis.
4. To balance the telescope on the Dec. axis, rst tighten
the R.A. lock knob, with the counterweight shaft still in the
horizontal position.
5. With one hand on the telescope optical tube, loosen the
Dec. lock knob. The telescope should now be able to rotate
freely about the Dec. axis (Figure 20b). Loosen the tube
Ring clamp
knob
Latitude
scale
Figure 15. Lay the optical tube in the open tube ring, then
close the ring and clamp it with the tube ring clamp knob.
Latitude
adjustment
bolt
Finderscope base
Figure 16.
into the base near the focuser as shown.
Insert the red dot nder scope’s bracket foot
Foot
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loosen the lock knob on one or both axes and manually point
the telescope, it should move without resistance and should
not drift from where you point it.
Thumbscrew
Focuser
Eyepiece
Figure 17. Eyepiece is shown installed in the focuser.
Power switch
Opposite side
Focus
wheel
Plastic
4. Understanding and Using
the Equatorial Mount
When you look at the night sky, you no doubt have noticed
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 is designed to compensate
for that motion, allowing you to easily “track” the movement of
astronomical objects, thereby keeping them from drifting out
of the telescope’s eld of view while you’re observing.
This is accomplished by slowly rotating the telescope on its
right ascension (R.A.) axis, using only the R.A. slow-motion
cable. But rst the R.A. axis of the mount must be aligned
with the Earth’s rotational (polar) axis—a process called polar
alignment.
Polar Alignment
For Northern Hemisphere observers, approximate polar alignment is achieved by pointing the mount’s right ascension axis
at the North Star (Polaris). It lies within 1° of the north celestial pole (NCP), which is an extension of the Earth’s rotational
tab
Vertical knob
Horizontal knob
Figure 18. The red dot nder scope has vertical and (inset)
horizontal adjustment knobs for aligning it with the telescope.
ring clamp knob a few turns, until you can slide the telescope tube forward and back inside the ring. Using a slight
twisting motion on the optical tube can help move the tube
within the ring.
6. Position the telescope so it remains horizontal when you
carefully let go with both hands. This is the balance point.
Before clamping the tube ring tight again, rotate the telescope so the eyepiece is at a convenient angle for viewing. When you are actually observing with the telescope,
you can adjust the eyepiece position by loosening the tube
ring and rotating the optical tube.
7. Retighten the tube ring clamp knobs.
The telescope is now balanced on both axes. Now when you
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Dec. lock
knob
Dec. setting
circle
Latitude
adjustment bolt
R.A. lock
knob
Latitude
lock
knob
R.A. setting
circle
Figure 19. Get to know the knobs and setting circles on the
equatorial mount.
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Little Dipper
(in Ursa Minor)
a.
b.
Figure 20.
Dec. axes.
Balancing the telescope about the a) R.A. and b)
axis out into space. Stars in the Northern Hemisphere appear
to revolve around the NCP.
To nd Polaris in the sky, look north and locate the pattern of
the Big Dipper (Figure 21). The two stars at the end of the
“bowl” of the Big Dipper point approximately to Polaris.
Observers in the Southern Hemisphere aren’t so fortunate to
have a bright star so near the south celestial pole (SCP). The
Big Dipper
(in Ursa Major)
Pointer
Stars
N.C.P.
Polaris
Cassiopeia
Figure 21. To nd Polaris in the night sky, look north and nd
the Big Dipper. Extend an imaginary line from the two "Pointer
Stars" in the bowl of the Big Dipper. Go about ve times the
distance between those stars and you'll reach Polaris, which lies
within 1° of the north celestial pole (NCP).
star Sigma Octantis lies about 1° from the SCP, but it is barely
visible with the naked eye (magnitude 5.5).
To polar align the equatorial mount:
1. Roughly level the equatorial mount by adjusting the length
of the three tripod legs as needed.
2. Loosen the latitude lock knob (see Figure 19). Turn the lati-
tude adjustment bolt until the pointer on the latitude scale
is indicating the latitude of your observing location (Figure
15). If you don’t know your latitude, you can look it up on
the internet. For example, if your latitude is 35° North, set
the pointer to 35. Then retighten the latitude lock knob. The
latitude setting should not have to be adjusted again unless
you move to a different viewing location some distance
away.
3. Loosen the Dec. lock knob and rotate the telescope optical
tube until it is parallel with the R.A. axis, as it is in Figure
2. The pointer on the Dec. setting circle should read 90°.
Retighten the Dec. lock knob.
4. Loosen the azimuth lock knob at the base of the equatorial
mount (Figure 7b) a half turn or so and rotate the mount
so the R.A. axis points roughly at Polaris. If you cannot see
Polaris directly from your observing site, consult a compass and rotate the mount so the telescope points North.
Retighten the azimuth lock knob.
The equatorial mount is now polar aligned. From this point
on in your observing session, you should not make any
further adjustments to 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 R.A. and Dec. axes.
Using the R.A. and Dec. Slow-Motion Control
Cables
The R.A. and Dec. slow-motion control cables allow fine
adjustment of the telescope’s position to center objects within
the eld of view. Before using the cables, manually “slew” the
mount to point the telescope in the vicinity of the desired target. Do this by loosening the R.A. and Dec. lock knobs (Figure
19) and moving the telescope about the mount’s R.A. and Dec.
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axes. Once the telescope is pointed somewhere close to the
object to be viewed, retighten the mount’s R.A. and Dec. lock
knobs.
The object should now be visible somewhere in the eld of
view of the red dot nder scope. If it isn’t, use the slow-motion
controls to scan the surrounding area of sky. Note: when
using the slow motion cables, the R.A. and Dec lock
knobs should be tightened, not loose. When the object
is visible in the nder scope, use the slow-motion controls to
center the red dot on it. Now, look in the telescope’s eyepiece
and use the slow-motion controls to center it in the eyepiece.
The Dec. slow-motion control cable can move the telescope a
maximum of 25° or so. This is because the Dec. slow-motion
mechanism has a limited range of mechanical travel. (The
R.A. slow-motion mechanism has no limit to its amount of
travel.) If you can no longer rotate the Dec. control cable in a
desired direction, you have reached the end of travel, and the
slow-motion mechanism must be reset. This is done by rst
rotating the control cable several turns in the opposite direction from which it was being turned. Then, manually slew the
telescope closer to the object you wish to observe (remember
to rst loosen the Dec. lock knob). You should now be able to
use the Dec. slow-motion control cable again to ne adjust the
telescope’s position.
Tracking Celestial Objects
When you observe a celestial object through the telescope,
you’ll see it drift slowly across the eld of view. To keep it in
the eld, assuming your equatorial mount is polar aligned, just
turn the R.A. slow-motion control cable clockwise, if the slowmotion cable is mounted on the EAST side of the mount. If
it’s on the WEST side of the mount, turn it counterclockwise
to track. The Dec. slow-motion control cable is not needed for
tracking. Objects will appear to move faster at higher magnications, because the eld of view is narrower.
Optional Electronic Drive for Automatic Tracking
An optional DC electronic drive can be mounted on the R.A.
axis of the equatorial mount to provide hands-free tracking.
Objects will then remain stationary in the eld of view without
any manual adjustment of the R.A. slow-motion control cable.
Understanding the Setting Circles
The two setting circles (Figure 19) on an equatorial mount
enable you to locate celestial objects by their “celestial coordinates”. Every object resides in a specic 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. R.A. is similar to longitude on Earth, and Dec.
is similar to latitude. The R.A. and Dec. values for celestial
objects can be found in any star atlas or star catalog.
The mount’s R.A. setting circle is scaled in hours, from 1
through 24, with small marks in between representing 10-minute increments. The numbers closest to the R.A. axis gear
apply to viewing in the Southern Hemisphere, while the numbers above them apply to viewing in the Northern Hemisphere.
The Dec. setting circle is scaled in degrees, with each mark
representing 2.5° increments. Values of Dec. coordinates
range from +90° to -90°. The 0° mark indicates the celestial
equator. When the telescope is pointed north of the celestial
equator, values of the Dec. setting circle are positive, while
when the telescope is pointed south of the celestial equator,
values of the Dec. setting circle are negative.
So, the coordinates for the Orion Nebula are:
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 properly polar aligned, and the R.A. setting circle must be calibrated. The Dec. setting circle has been permanently calibrated at the factory, and should read 90° whenever the telescope optical tube is parallel with the R.A. axis.
Calibrating the Right Ascension Setting Circle
Identify a bright star in the sky near the celestial equator
(Dec. = 0°) and look up its coordinates in a star atlas.
1. Loosen the R.A. and Dec. lock knobs on the equatorial
mount, so the telescope optical tube can move freely.
2. Point the telescope at the bright star whose coordinates
you know. Lock the R.A. and Dec. lock knobs. Center the
star in the telescope’s eld of view with the slow-motion
control cables.
3. Rotate the setting circle until the metal arrow indicates the
R.A. coordinate listed in the star atlas for the object.
Finding Objects with the Setting Circles
1. Now that both setting circles are calibrated, look up in a
star atlas the coordinates of an object you wish to view.
2. Loosen the R.A. lock knob and rotate the telescope until
the R.A. value from the star atlas matches the reading on
the R.A. setting circle. Remember to use the upper set
of numbers on the R.A. setting circle. Retighten the lock
knob.
3. Loosen the Dec. lock knob and rotate the telescope until
the Dec. 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 knob.
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 eld of view of the red
dot nder scope, assuming the equatorial mount is accurately polar aligned. Use the slow-motion controls to center the
object in the nder scope, and it should appear in the telescope’s eld of view.
The R.A. setting circle must be re-calibrated every time you
wish to locate a new object. Do so by calibrating the setting
circle for the centered object before moving on to the next one.
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Confused About Pointing the Telescope?
Beginners occasionally experience some confusion about
how to point the telescope overhead or in other directions.
One thing you DO NOT do is make any adjustment to the
mount’s latitude setting or to its azimuth position (don’t touch
the azimuth lock knob). That will throw off the mount’s polar
alignment. Once the mount is polar aligned, the telescope
should be moved only about the R.A. and Dec. axes by loosening one or both of the R.A. and Dec. lock knobs and moving
the telescope by hand, or keeping the knobs tightened and
moving the telescope using the slow-motion cables.
5. Astronomical Observing
For many, this will be your rst foray into the exciting world of
amateur astronomy. The following information and observing
tips will help get you started.
Choosing an Observing Site
When selecting a location for observing, get as far away as
possible from direct articial light such as street lights, porch
lights, and automobile headlights. The glare from these lights
will greatly impair your dark-adapted night vision. Set up on
a grass or dirt surface, not asphalt, because asphalt radiates
more heat. Heat disturbs the surrounding air and degrades
the images seen through the telescope. Avoid viewing over
rooftops and chimneys, as they often have warm air currents
rising from them. Similarly, avoid observing from indoors
through an open (or closed) window, because the temperature difference between the indoor and outdoor air will cause
image blurring and distortion.
If at all possible, escape the light-polluted city sky and head
for darker country skies. You’ll be amazed at how many more
stars and deep-sky objects are visible in a dark sky!
“Seeing” and Transparency
Atmospheric conditions vary signicantly from night to night.
“Seeing” refers to the steadiness of the Earth’s atmosphere
at a given time. In conditions of poor seeing, atmospheric
turbulence causes objects viewed through the telescope
to “boil.” If you look up at the sky and stars are twinkling
noticeably, the seeing is poor and you will be limited to viewing
at lower magnications. At higher magnications, images will
not focus clearly. Fine details on the planets and Moon will
likely not be visible.
In conditions of good seeing, star twinkling is minimal and
images 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.
Especially important for observing faint objects is good
“transparency”— air free of moisture, smoke, and dust. All
tend to scatter light, which reduces an object’s brightness.
Transparency is judged by the magnitude of the faintest stars
you can see with the unaided eye (5th or 6th magnitude is
desirable).
Cooling the Telescope
All optical instruments need time to reach “thermal equilibrium.” The bigger the instrument and the larger the temperature
change, the more time is needed. Allow at least 30 minutes
for your telescope to acclimate to the temperature outdoors
before you start observing with it.
Let Your Eyes Dark-Adapt
Don’t 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. As your eyes become darkadapted, more stars will glimmer into view and you’ll be able
to see fainter details in objects you view in your telescope.
To see what you’re doing in the darkness, use a red-ltered
ashlight rather than a white light. Red light does not spoil
your eyes’ dark adaptation like white light does. A ashlight
with a red LED light is ideal. Beware, too, that nearby porch,
streetlights, and car headlights will ruin your night vision.
Eyepiece Selection
Magnication, or power, is determined by the focal length of
the telescope and the focal length of the eyepiece being used.
Therefore, by using eyepieces of different focal lengths, the
resultant magnication can be varied. It is quite common for an
observer to own ve or more eyepieces to access a wide range
of magnications. This allows the observer to choose the best
eyepiece to use depending on the object being viewed and
viewing conditions. Your SpaceProbe II 76mm EQ comes with
25mm (W) and 10mm (X) Kellner eyepieces, which will suffice
nicely to begin with. You can purchase additional eyepieces
later if you wish to have more magnication options.
Magnication is calculated as follows:
Telescope Focal Length (mm)
For example, the SpaceProbe II 76mm EQ has a focal length
of 700mm, which when used with the supplied 25mm eyepiece yields:
The magnication provided by the 10mm eyepiece is:
The maximum attainable magnification for a telescope is
directly related to how much light it can gather. The larger the
aperture, the more magnication is possible. In general, a gure of 50x per inch of aperture is the maximum attainable for
most telescopes. Going beyond that will yield simply blurry,
unsatisfactory views. Your SpaceProbe II 76mm EQ has an
aperture of 76mm, or 3.0 inches, so the maximum magnication would be about 150x (3.0 x 50). This level of magnication
assumes you have ideal atmospheric conditions for observing
(which is seldom the case).
= Magnication
Eyepiece Focal Length (mm)
700 mm
= 28x
25 mm
700 mm
= 70x
10 mm
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Keep in mind that as you increase magnication, the brightness of the object viewed will decrease; this is an inherent
principle of the laws of physics and cannot be avoided. If magnication is doubled, an image appears four times dimmer.
If magnication is tripled, image brightness is reduced by a
factor of nine!
Start by centering the object you wish to see in the 25mm
eyepiece. Then you may want to increase the magnication
to get a closer view, by switching to the 10mm eyepiece. If
the object is off-center (i.e., it is near the edge of the eld of
view) you will lose it when you increase magnication, since
the eld of view will be narrower with the higher-powered
eyepiece. So make sure it is centered in the 25mm eyepiece
before switching to the 10mm eyepiece.
Focusing the Telescope
To focus the telescope, turn the focus wheels (Figure 17)
forward or back until you see your target object (e.g., stars,
the Moon, etc.) in the eyepiece. Then make ner adjustments
until the image is sharp. If you’re having trouble achieving initial focus, rack the focuser drawtube all the way in using the
focus wheels, then while looking into the eyepiece slowly turn
the focus wheels so that the drawtube extends outward. Keep
going until you see your target object come into focus. Note
that when you change eyepieces you may have to adjust the
focus a bit to get a sharp image with the newly inserted 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 many bright
deep-sky objects. Do not expect to see color as you do 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 few of the
brightest ones.
Objects to Observe
Now that you are all set up and ready to go, what is there to
look at in the night sky?
A. The Moon
With its rocky surface, the Moon is one of the easiest and most
interesting objects to view with your telescope. Lunar craters,
maria, and even mountain ranges can all be clearly seen from
a distance of 238,000 miles away! With its ever-changing
phases, you’ll get a new view of the Moon every night. The
best time to observe our one and only natural satellite is during a partial phase, that is, when the Moon is not full. During
partial phases, shadows are cast on the surface, which reveal
more detail, especially right along the border between the dark
and light portions of the disk (called the “terminator”). A full
Moon is too bright and devoid of surface shadows to yield a
pleasing view. Make sure to observe the Moon when it is well
above the horizon to get the sharpest images.
Use an optional Moon lter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepieces (you
must rst remove the eyepiece from the focuser to attach a
lter). You’ll nd that the Moon lter improves viewing comfort,
and helps to bring out subtle features on the lunar surface.
B. The Planets
The planets don’t stay put like the stars, so to nd them you
should refer to the monthly star charts at OrionTelescopes.
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. Other planets may be visible but will likely
appear star-like. Because planets are quite small in apparent
size, optional higher-power eyepieces or a Barlow lens are
recommended and often needed for detailed observations.
B. The Sun
You can change your nighttime telescope into a daytime Sun
viewer by installing an optional full-aperture solar lter over the
front opening of the telescope. The primary 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.
Important Note: Do not look at the Sun with any optical instrument without a professionally made solar lter, or permanent
eye damage could result.
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 favorites.
Defocusing a star slightly can help bring out its color.
E. 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 different types of galaxies. Most deep-sky
objects are very faint, so it is important you nd an observing
site well away from light pollution.
To nd deep-sky objects with your telescope, you rst need
to become reasonably familiar with the night sky. Unless you
know how to recognize the constellation Orion, for instance,
you won’t have much luck locating the Orion Nebula. A simple
planisphere, or star wheel, can be a valuable tool for learning
the constellations and seeing which ones are visible in the sky
on a given night. Once you have identied a few constellations,
a good star chart, atlas, or astronomy app will come in handy
for helping locate interesting deep-sky objects to view within
the constellations.
Do not expect these objects to appear like the photographs
you see in books and on the internet; most will look like dim
gray smudges. Our eyes are not sensitive enough to see color
in deep-sky objects except in a few of the brightest ones. 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.
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Reection of
secondary
mirror
b.
a.
Figure 22. Collimating the optics. a) When the mirrors are properly aligned, the view down the focuser drawtube should
look like this. b) If the optics are out of alignment, the view might look something like this (with a collimation cap or Cheshire
eyepiece in place). Here, only part of the primary mirror is visible in the secondary mirror, so the secondary mirror needs
to be adjusted (tilted). c) Here the secondary mirror is correctly aligned because the entire primary mirror is visible in it. But
the reection of the secondary mirror is off-center. So the primary mirror still needs adjustment. d) Now the primary mirror is
correctly aligned, so the secondary mirror is centered.
6. Useful Optional
Accessories
• Moon Filter – A 1.25" Moon lter will cut down the strong
glare of sunlight reected from the Moon, making Moon viewing
more comfortable and revealing more surface detail. The lter
threads into the bottom of the Kellner eyepieces that came with
your telescope (Figure 26).
• Motor Drive – A motor drive, which attaches to the right
ascension axis of an equatorial telescope mount, enables your
telescope to “track” the motion of stars and other celestial objects
as they drift slowly from east to west in the night sky. This keeps
them in the eyepiece eld of view indenitely, instead of drifting
out of sight.
• Barlow Lens – A 2x Barlow lens doubles the magnifying
power of any eyepiece it’s used with, giving you a big power
boost to get in closer to your target object. You just insert it
between the diagonal and the eyepiece.
• Planisphere – A nifty “star wheel” that shows what stars and
constellations are visible in the sky at any time of any night. Just
set the date and time see a mini representation of your local
night sky. Great for identifying what you see and planning an
evening’s observing session.
• Star Map – More detailed than a planisphere, a star map is
essential for locating interesting celestial objects to observe with
your telescope. Nowadays many mobile astronomy apps feature
customizable star maps that you can access on your smartphone or tablet while you’re at the telescope.
c.
7. Aligning the Mirrors
(Collimation)
Collimation is the process of adjusting the optics of a telescope so they are precisely aligned with one another and with
the telescope tube. For this reector telescope, the primary
and secondary mirrors must be in precise alignment. Your
telescope’s optics were aligned at the factory, and should not
need much or any 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
occasionally. With practice, collimating is relatively easy to do
and can be done in daylight.
It helps to perform the collimation procedure in a brightly lit
room with the telescope pointed toward a bright surface, such
as a light-colored wall. Placing a piece of white paper in the
telescope tube opposite the focuser (i.e., on the other side of
the secondary mirror from the focuser) will also be helpful.
You will need a Phillips screwdriver to adjust the mirrors.
To check your telescope’s collimation, remove the eyepiece
and look down the focuser. You should see the secondary
mirror centered in the focuser, as well as the reection of
the primary mirror centered in the secondary mirror, and the
reection of the secondary mirror (and your eye) centered in
the reection of the primary mirror, as in Figure 22a. Got all
that? Review it again carefully, and compare what you see to
Figure 22a. If anything is off-center, proceed with the following collimation procedure.
d.
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NOTE: Precise collimation is best achieved by using an
optional collimating tool, such as a quick-collimation cap,
a Cheshire eyepiece, or a laser collimator. Check our website for available collimating tools. Figures 22b through 22d
assume that you have an optional Cheshire eyepiece or collimation cap in the focuser.
Primary Mirror Center Mark
You may have noticed that your SpaceProbe II 76mm reector has a tiny ring (sticker) in the exact center of the primary
mirror. This “center mark” allows you to achieve a very precise collimation of the primary mirror; you don’t have to guess
where the center of the mirror is, which is important in the
collimation process. This center mark is especially useful
when using an optional collimating device, such as Orion’s
LaserMate Deluxe II laser collimator.
NOTE: The center ring sticker should not 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 counter-intuitive, but it’s true! Leave it in
place.
Aligning the Secondary Mirror
Align the secondary mirror rst. Look down the focuser at the
secondary (diagonal) mirror. If the entire primary mirror reection is not visible in the secondary mirror, as in Figure 22b,
you will need to adjust the tilt of the secondary mirror. This is
done by alternately loosening one of the three
secondary mirror alignment screws with a Phillips screwdriver
then tightening the other two (Figure 23). The goal is to center the primary mirror reection in the secondary mirror, as
in Figure 22c. Don’t worry that the reection of the second-
ary mirror (the smallest circle) is off-center. You will x that
in the next step. It will take some trial and error to determine
which screws to loosen and tighten to move the reection of
the primary mirror to the center of the secondary mirror. But
bepatient and you’ll get it.
Aligning the Primary Mirror
The nal adjustment is made to the primary mirror. It will need
adjustment if, as in Figure 22c, the reection of the primary
mirror is centered in the secondary mirror, but the small reection of the secondary mirror is off-center. The tilt of the primary
mirror is adjusted using the three pairs of collimation screws
on the back end of the optical tube (Figure 24). Adjusting
the tilt of the mirror requires a “push-pull” technique involving
adjustment of one or more pairs of collimation screws.
With a Phillips screwdriver, loosen one of the screws one full
turn, and then tighten the adjacent screw (the one right next
to it) until it is tight. Look into the focuser and see if the secondary mirror reection has moved closer to the center of the
primary. You can tell this easily by simply watching to see if
the “dot” of the Cheshire eyepiece or collimation cap is moving closer or farther away from the ring on the center of the
primary mirror. Repeat this process on the other two sets of
collimation screws, if necessary. Again, it will take a little trial
and error to get a feel for how to tilt the mirror in this way.
When you have the dot centered as much as possible in the
ring, your primary mirror is collimated. The view through the
collimation cap should resemble Figure 22d. Make sure all
the collimation screws are tight (but do not overtighten), to
secure the mirror tilt. A simple star test will tell you whether the
optics are accurately collimated.
Star-Testing the Telescope
When it is dark, point the telescope at a bright star and accurately center it in the eyepiece’s eld of view. Slowly de-focus
the image with the focusing knob. If the telescope is correctly collimated, the expanding disk should be a perfect circle
(Figure 25). If the image is unsymmetrical, the scope is out
of collimation. The dark shadow cast by the secondary mir-
Figure 23. Adjust the tilt of the secondary mirror by adjusting
the three alignment screws with a Phillips screwdriver.
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Figure 24. Align the primary mirror by adjusting the three pairs
of “push/pull” screws on the back end of the optical tube.
Page 15
ror should appear in the very center of the out-of-focus circle,
Out of collimation Collimated
like the hole in a donut. 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, 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.
Figure 25.
properly collimated.
A star test will determine if the telescope's optics are
Your SpaceProbe II 76mm EQ telescope requires very little
mechanical maintenance. The optical tube is steel and has
a smooth painted nish that is fairly scratch resistant. If a
scratch does appear, it will not harm the telescope.
Cleaning Optics
You should not have to clean the telescope’s mirrors. Covering
the telescope with the dust cap when it is not in use will help prevent dust from accumulating on the mirrors. Even a little dust on
the mirror surfaces will not affect the optical performance in any
way. If you feel the mirrors need to be cleaned, please contact
Orion Customer Service at 800-676-1343 for guidance.
To clean the eyepiece lenses, any quality optical lens cleaning tissue and optical lens cleaning uid specically designed
for multi-coated optics can be used. Never use regular glass
cleaner or cleaning uid designed for eyeglasses. Before cleaning, remove any loose particles or dust from the lens with a
blower bulb or soft brush. Then apply some cleaning uid to a
tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess uid with a fresh lens tissue. Oily ngerprints 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.
When bringing the telescope inside after an evening’s viewing
it is normal for moisture to accumulate on the lenses due to the
change in temperature. We suggest leaving the telescope and
eyepieces uncovered overnight to allow the condensation to
evaporate.
Figure 26. The Kellner eyepieces have barrels threaded to
accept optional Orion 1.25” lters. A Moon lter is useful for cutting
glare and revealing more detail on the lunar surface.
8. Telescope 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
caps on the front of the telescope and on the focuser drawtube when not in use.
9. Specifications
Optical tube material: Rolled steel
Primary mirror diameter: 76mm (3.0")
Primary mirror coating: Aluminum with silicon dioxide
(SiO2) overcoat
Secondary mirror minor axis dia.: 19.9mm
Focal length: 700mm
Focal ratio: f/9.2
Focuser: Rack-and-pinion, accepts 1.25" accessories
Eyepieces: 25mm and 10mm Kellner, antireection coated,
1.25" barrel diameter, threaded for Orion lters
Eyepiece magnication: 28x (with 25mm eyepiece) and 70x
(with 10mm eyepiece)
Finder scope: Red dot nder scope
Mount: German equatorial
Tripod: Aluminum
Motor drive: Optional
Total instrument weight: 11 lbs., 11 oz.
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One-Year Limited Warranty
This Orion product is warranted against defects in materials or workmanship for a period of one year from the date
of purchase. This warranty is for the benet 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. Proof of purchase (such as a copy of the original receipt) is required. This
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishandled, or modied, nor
does it apply to normal wear and tear. This warranty gives you specic legal rights. It is not intended to remove or
restrict your other legal rights under applicable local consumer law; your state or national statutory consumer rights
For further warranty information, please visit www.OrionTelescopes.com/warranty.
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Customer Support: www.OrionTelescopes.com/contactus
All Rights Reserved. No part of this product instruction or any of its contents may be reproduced, copied, modified or adapted, without the prior
16
warranty is only valid in the country of purchase.
governing the sale of consumer goods remain fully applicable.
Orion® Telescopes & Binoculars
Copyright © 2017 Orion Telescopes & Binoculars
written consent of Orion Telescopes & Binoculars.
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