SKY-WATCHER S11670, S11600, REFRACTOR, SCHMIDT-CASSEGRAIN, EQ5 Pro User Manual

Telescopes with EQ5 Mount

091508 v2

REFRACTOR

MANUAL EQ5 PRO

D

E

F

A

B

C

EQ5

TUBE

A. Dust Cap/Mask
(Remove before Viewing)
B. Sun Shade
C. Objective Lens
D. Telescope Main Body
E. Piggyback Bracket
F. Tube Rings
G. 8x50 View finder or
Red Dot Finder
H. Finderscope Bracket
I. Alignment Screw
J. Eyepiece
K. Diagonal
L. Focus Tube / Draw Tube
M. Focus Knob

MOUNT / TRIPOD

1. Polarscope Holder

2. Altitude Adjustment T-bolts

3. Azimuth Adjustment Knob

4. Counterweight Rod

5. Counterweight

6. Counerweight Thumb
Screw

7. R. A. Control Knob

8. R.A. Lock Knob

9. Dec. Lock Knob

10. Dec. Control Knob

11. Mounting Plate
(150mm/1200mm)

12. Accessor y Tray

13. Tripod Leg

G

(150mm/1200mm)

H

I

J

11

10

9

8

7

6

5

L

M

1

4

2

K

3

12

13

2

REFLECTOR

MANUAL EQ5 PRO

EQ5

TUBE

A. Dust Cap/Mask
(Remove before Viewing)
B. Focus Tube
C. Red Dot Finder or
8x50 View finder
D. Eyepiece
E. Focus Knob
F. Piggyback Bracket
G. Tube Rings
H. Telescope Main Body
I. Primary Mirror Position

B

A

C

D

E

F

G

H

I

11

10

9

8

(200mm/1000mm)

7

1

2

6

3

4
5

12

13

MOUNT / TRIPOD

1. Mounting Plate
(200mm/1000mm)

2. R.A. Control Knob

3. Polarscope Holder
(not shown)

4. Altitude Adjustment T-bolts

5. Azimuth Adjustment Knob

6. Counterweight

7. Counerweight Thumb
Screw

8. Counterweight Rod

9. R.A. Lock Knob

10. Dec. Lock Knob

11. Dec. Control Knob

12. Accessor y Tray

13. Tripod Leg

3

MAKSUTOV & SCHMIDT-CASSEGRAIN

MANUAL EQ5 PRO

A

B

C

EQ5

TUBE

A. Dust Cap/Mask (Not shown
remove before viewing)
B. Red Dot Finder or
8x50 View finder
C. Focus Locking Screw
D. Eyepiece
E. Diagonal
F. Focusing Knob

E

D

9

8

F

1

2

7

3

6

4

5

10

11

MOUNT / TRIPOD

1. R.A. Lock Knob

2. Dec. Flexible Control Cable

3. Polarscope Holder /
Polarscope (not shown,
optional)

4. Altitude Adjustment T-bolt

5. Azimuth Adjustment Knobs

6. Counerweight Locking
Thumb Screw

7. Counterweight Rod

8. Dec. Lock Knob

9. Dec. Setting Circle

10. Accessor y Tray

11. Hight Adjustment Clamp

4

TABLE OF CONTENTS: EQ5 PRO

Assembling Your Telescope

Tripod Set up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Mount Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Telescope Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Finderscope Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Eyepiece Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Telescope Assembly - Attaching Mounting Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Operating Your Telescope

Aligning the Finderscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Using the Red Dot Finder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Balancing the telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Using the leveling bubble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Operating the EQ5 Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Using the Barlow Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Focusing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Polar Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Tracking celestial objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Using the setting circles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Using the Polarscope (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pointing your telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Choosing the appropriate eyepiece . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Observing the Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Sky Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Selecting an Observing Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Choosing the Best Time to Observe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Cooling the Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Adapting Your Eyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Proper Care for Your Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Collimating a Newtonian reflector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Collimating a refractor (with the adjustable objective-lens cell) . . . . . . . . . . . . . . . 25

Cleaning Your Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Appendix A - Standard Time Zones of the World . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Appendix B - Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Appendix C - Recommended Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Appendix D - Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Before you begin

This instruction manual is applicable to all the
models with the EQ5 mount. Take a moment to
find the model closest to your telescope on p.2,
p.3, and p.4. Follow the instructions for your
specific model in the manual. Read the entire
instructions carefully before beginning. Your
telescope should be assembled during daylight
hours. Choose a large, open area to work to
allow room for all parts to be unpacked.

aution!

C

NEVER USE YOUR TELESCOPE TO LOOK DIRECTLY AT
THE SUN. PERMANENT EYE DAMAGE WILL RESULT.
USE A PROPER SOLAR FILTER FOR VIEWING THE SUN.
WHEN OBSERVING THE SUN, PLACE A DUST CAP OVER
YOUR FINDERSCOPE TO PROTECT IT FROM
EXPOSURE. NEVER USE AN EYEPIECE-TYPE SOLAR
FILTER AND NEVER USE YOUR TELESCOPE TO
PROJECT SUNLIGHT ONTO ANOTHER SURFACE, THE
INTERNAL HEAT BUILD-UP WILL DAMAGE THE
TELESCOPE OPTICAL ELEMENTS.

5

Fig. 1

Fig. 3

ASSEMBLING YOUR TELESCOPE

TRIPOD SET UP

ASSEMBLING THE TRIPOD LEGS (Fig.1)

1) Slowly loosen the height adjustment clamp
and gently pull out the lower section of
each tripod leg. Tighten the clamps to hold
the legs in place.

2) Spread the tripod legs apart to stand
the tripod upright.

3) Place a carpenter's level or bubble level on
the top of the tripod legs. Adjust the height of
each tripod leg until the tripod head is properly
leveled. Note that the tripod legs may not be at
same length when the equatorial mount is level.

ATTACHING MOUNT TO TRIPOD LEGS (Fig. 2)

1) Align metal dowel on the tripod head with the gap
between the azimuth adjustment knobs underneath
the mount.

2) Push the primary locking shaft up against the
mount and turn the knurled knob underneath to
secure mount to tripod.

Fig. 2.

Fig.4

ATTACHING THE ACCESSORY TRAY (Fig. 3)

1) Slide the accessory tray along the primary locking
shaft until it pushes against the tripod legs.

2) Secure with the washer and locking knob.

Note: Loosen the azimuth adjustment knobs if mount does not
fit into tripod head completely. Retighten knobs to secure.

MOUNT ASSEMBLY

INSTALLING COUNTERWEIGHT (Fig.4, 5)

1) Locate counterweight rod.

2) Screw counterweight rod into threaded
hole on the end of the declination
shaft. Tighten locknut on the
counterweight rod until it is locked
against the mount.

3) Unscrew the threaded cap from the
end of the counterweight rod.

4) Locate the counterweights and slide
them halfway along the counterweight
rod. Tighten the counterweight thumb
screws to secure.

5) Replace the cap on the end of the
counterweight rod.

Fig.5

6

TELESCOPE ASSEMBLY

ATTACHING THE TUBE RINGS TO THE MOUNT (Fig.6)

1) Remove the telescope tube assembly from

its plastic packaging.

2) Remove the tube rings from the telescope by
releasing their thumb nuts and opening their hinges.

3) Using the bolts provided, fasten the tube rings to
the mount with the 10mm wrench provided.

ATTACHING THE TELESCOPE MAIN TUBE
TO THE TUBE RINGS (Fig.7)

1) Remove the telescope tube from the paper covering.

2) Find the center of balance of the telescope tube.
Place this in between the two tube rings. Close the
hinges around the telescope and fasten securely by
tightening the thumb nuts. Do not over tighten.

Fig.6

Fig.7

FINDERSCOPE/RED DOT FINDER ASSEMBLY

ATTACHING THE FINDERSCOPE

BRACKET/RED DOT FINDER (Fig. 8)

Reflector and Maksutov Refractor

Fig.8

1) Locate the finderscope optical assembly
or Red Dot Finder.

2) Slide the finderscope bracket/Red Dot
Finder into the rectangular slot and tighten
the screw to hold the mount in place.

ATTACHING THE FINDERSCOPE

(Fig. 9, 10, 11)

Fig.9

1) Locate the finderscope bracket.
Carefully remove the rubber-o­ ring from the finderscope bracket.

2) Position the o-ring into the
groove located approximately

Fig.10

Fig.11

half-way along the finderscope
tube.

3) Locate the finderscope optical
assembly.

4) Slide the finderscope bracket
into the rectangular slot and
tighten the screw to hold the
mount in place.

5) Position the finderscope into
its mount by sliding it backwards

until the rubber o-ring seats
in the finderscope mount.

7

EYEPIECE ASSEMBLY

INSERTING THE EYEPIECE (Fig.12, 13) INSERTING THE EYEPIECE (Fig.14)

Refractor and MaksutovReflector

1) Unscrew the
thumbscrews on the
end of the focus tube
to remove the black
plastic end-cap.

Fig.12

Fig.13

2) Insert the desired
eyepiece and secure
it by retightening the
thumbscrews.

HAND CONTROL HOLDER INSTALLATION

INSTALLING THE HAND CONTROL
HOLDER (Fig.15, 16)

Locate the hand control holder. Slide
the holder onto the accessory tray as
shown in Fig.16.

(for SynScan only)

1) Loosen the thumbscrew on the
end of the focus tube.

2) Insert the diagonal into the focus
tube and re-tighten the
thumbscrew to hold the diagonal
in place.

3) Loosen the thumbscrews on the
diagonal.

4) Insert the desired eyepiece into
diagonal and secure by
re-tightening the thumbscrews.

Fig.14

Fig.15

TELESCOPE ASSEMBLY

ATTACHING THE MOUNTING PLATE
(Fig.17)

1) Position the mounting plate on the
mounting bracket.

2) Secure by tightening the two locking
screws.

Fig. 17

(diagram applicable to both mounts)

Fig.16

ATTACHING THE TUBE
RINGS (Fig.18)

1) Remove the telescope
tube assembly from its
plastic packaging.

2) Remove the tube rings
from the telescope by
releasing their thumb nuts
and opening their hinges.

3) Using the bolts provided,
fasten the tube rings to the
mount with the 10mm
wrench provided.

(Please attach the tube rings to the mounting plate as shown if the rings are not
already attached)

Fig. 18

8

ligning the finderscope

A

Fig.a

Fig.a1

OPERATING YOUR TELESCOPE

These fixed magnification scopes mounted on the optical tube
are very useful accessories. When they are correctly aligned
with the telescope, objects can be quickly located and brought
to the centre of the field. Alignment is best done outdoors in
day light when it's easier to locate objects. If it is necessary to
refocus your finderscope, sight on an object that is at least
500 yards (metres) away. Loosen the locking ring by
unscrewing it back towards the bracket. The front lens holder
can now be turned in and out to focus. When focus is
reached, lock it in position with the locking ring (Fig.a).

1)
Choose a distant object that is at least 500 yards away and

point the main telescope at the object. Adjust the telescope
so that the object is in the centre of the view in your
eyepiece.

2)

Check the finderscope to see if the object centred in the
main telescope view is centred on the crosshairs.

3)

Adjust the two small screws to centre the finderscope
crosshairs on the object (Fig.a1).

sing the Red Dot Finder

U

The Red Dot Finder is a zero magnification pointing tool
that uses a coated glass window to superimpose the
image of a small red dot onto the night sky. The Red Dot
Finder is equipped with a variable brightness control,
azimuth adjustment control, and altitude adjustment
control (Fig.b). The Red Dot Finder is powered by a 3-volt
lithium battery located underneath at the front. To use the
Finder, simply look through the sight tube and move your
telescope until the red dot merges with the object. Make
sure to keep both eyes open when sighting.

Aligning the Red Dot Finder

Like all finderscopes, the Red Dot Finder must be properly
aligned with the main telescope before use. This is a
simple process using the azimuth and altitude control
knobs.

Open the battery cover by pulling it down (you can

1)
gently pry at the 2 small slots) and remove the plastic
shipping cover over the battery (Fig.b1).
Turn on the Red Dot Finder by rotating the variable

2)
brightness control clockwise until you hear a "click".
Continue rotating the control knob to increase the
brightness level.
Insert a low power eyepiece into the telescope's focuser.

3)
Locate a bright object and position the telescope so that
the object is in the centre of the field of view.
With both eyes open, look through the sight tube at the
object. If the red dot overlaps the object, your Red Dot

4)
Finder is perfectly aligned. If not, turn its azimuth and
altitude adjustment controls until the red dot is merged
with the object.

Fig.b

ON/OFF
Brightness
Control

Altitude
Adjustment
Control

Fig.b1

Azimuth
adjustment
control

Sight Tube

Battery cover

Plastic
shipping
cover

9

alancing the telescope

B

A Telescope should be balanced before each observing session. Balancing reduces stress on the telescope
mount and allows precise control of micro-adjustment. A balanced telescope is specially critical when using the
optional clock drive for astrophotography. The telescope should be balanced after all accessories (eyepiece,
camera, etc.) have been attached. Before balancing your telescope, make sure that your tripod is balanced and
on a stable surface. For photography, point the telescope in the direction you will be taking photos before
performing the balancing steps.

R.A. Balancing

1)

For best results, adjust the altitude of
the mount to between 15º and 30º if
possible, by using the altitude
adjustment T-bolt.

2)

Slowly unlock the R.A. and Dec. lock
knobs. Rotate the telescope until
both the optical tube and the
counterweight rod are horizontal to
the ground, and the telescope tube
is to the side of the mount (Fig.c).

3)

Tighten the Dec. lock knob.

4)

Move the counterweight(s) along the
counterweight rod until the
telescope is balanced and remains
stationary when released.

5)

Tighten the counterweight thumb
screws to hold counterweight(s) in
their new position.

Fig.c

N

Dec. Balancing

All accessories should be attached to the telescope before balancing around the declination axis. The R.A.
balancing should be done before proceeding with Dec. balancing.

1)

For best results, adjust the altitude of the mount to between 60º and 75º if possible.

2)

Release the R.A. lock knob and rotate around the R.A. axis so that the counterweight rod is in a horizontal
position. Tighten the R.A. lock knob.

3)

Unlock the Dec. lock knob and rotate the telescope tube until it is parallel to the ground.

4)

Slowly release the telescope and determine in which direction it rotates. Loosen the telescope tube rings and
slide the telescope tube forward or backward in the rings until it is balanced.

5)

Once the telescope no longer rotates from its parallel starting position, re-tighten the tube rings and the Dec. lock
knob. Reset the altitude axis to your local latitude.

sing the leveling bubble

U

For best telescope performance, the equatorial mount should
be properly leveled. A level tripod allows easier fine adjustment
of controls and better weight distribution. This equatorial mount
includes a small leveling bubble near its base (Fig.d). Adjust the
height of each tripod leg until the bubble appears in the center
of the circle. Note that the tripod legs may not be at same
length when the equatorial mount is level.

Fig.d

Leveling bubble

10

perating the EQ5 mount

O

The EQ5 mount has controls for both conventional altitude (up-down) and azimuth (left-right) directions of motion.
These two adjustments are suggested for large direction changes and for terrestrial viewing. The two azimuth
adjustment knobs located near the tripod head allow fine-adjustment of azimuth for polar alignment. Use the
altitude adjustment T-bolts for altitude adjustments. These allow fine-adjustment for setting the mount to your local
latitude. (Fig.e1).

In addition, this mount has Right Ascension (hour angle) and declination direction controls for polar-aligned
astronomical observing. Loosen the lock knobs to make large direction changes. Use the control cables for fine
adjustment after the lock knobs have both been locked (Fig.e2). An additional scale is included for the altitude
axis. This allows polar alignment for your local latitude. (Fig.f)

Fig.e1

Altitude
adjustment

Azimuth
adjustment

Dec. fine
adjustment

Dec. adjustment

Fig.e2

R.A. adjustment

R.A. fine
adjustment

Backside Latitude scale

0

10

20

30

40

50

60

Latitude scale

Fig.f

70
80

90

11

sing the Barlow lens (optional)

U

A Barlow is a negative lens which increases the magnifying
power of an eyepiece, while reducing the field of view. It
expands the cone of the focussed light before it reaches the
focal point, so that the telescope's focal length appears
longer to the eyepiece.

The Barlow is inserted between the focuser and the
eyepiece in a reflector, and usually between the diagonal
and the eyepiece in a refractor or a Maksutov (Fig.g). With
some telescopes, it can also be inserted between the
focuser and the diagonal, and in this position it gives even
greater magnification. For example, a 2X Barlow when
inserted after the diagonal can become 3X when placed in
front of the diagonal.

In addition to increasing magnification, the benefits of using
a Barlow lens include improved eye relief, and reduced
spherical aberration in the eyepiece. For this reason, a
Barlow plus a lens often outperform a single lens producing
the same magnification. However, it is greatest value may be
that a Barlow can potentially double the number of
eyepieces in your collection.

ocusing

F

Slowly turn the focus knobs under the focuser, one way or
the other, until the image in the eyepiece is sharp (Fig.h).
The image usually has to be finely refocused over time, due
to small variations caused by temperature changes, flexures,
etc. This often happens with short focal ratio telescopes,
particularly when they haven't yet reached outside
temperature. Refocusing is almost always necessary when
you change an eyepiece or add or remove a Barlow lens.

Fig.g

Fig.h

Barlow

Diagonal

(Refracting Telescopes
and Maksutovs)

Barlow

(Reflecting Telescopes)

Eyepiece

Eyepiece

P

olar

Alignmen

t

In order for your telescope to track objects in the sky you
have to align your mount. This means tilting the head over so
that it points to the North (or South) celestial pole. For
people in the Northern Hemisphere this is rather easy as the
bright star Polaris is very near the North Celestial Pole. For
casual observing, rough polar alignment is adequate. Make
sure your equatorial mount is level and the red dot finder is
aligned with the telescope before beginning.

Setting the latitude

Look up your latitude on a map, road maps are good for this
purpose. Now look at the side of your mount head, there you
will see a scale running from 0-90 degrees. At the base of
the head, just above the legs, are two screws opposite each
other under the hinge. All you have to do is loosen one side
and tighten the other until your latitude is shown by the
indicator pointer (Fig.i).

12

Fig.i

0

10

20

30

40

50

60

70
80

90

Latitude scale

Polaris, the "Pole Star" is less than one degree from the North
Celestial Pole (NCP). Because it is not exactly at the NCP, Polaris
appears to trace a small circle around it as the Earth rotates. Polaris
is offset from the NCP, toward Cassiopeia and away from the end of
the handle of the Big Dipper (Fig.i1).

Aligning your telescope to Polaris

Big Dipper

Fig.i1

Unlock the DEC lock knob and rotate the telescope tube until the
pointer on the setting circle reads 90°. Retighten the DEC lock knob.
Move the tripod so that the "N" at the base of the equatorial mount
faces north and the R.A. axis points roughly at Polaris. Use the two
azimuth adjustment knobs above the "N" to make fine adjustments in
azimuth if needed (Fig.i2). For more accurate alignment, look
through the finderscope and centre the Polaris on the crosshairs.

Along the R.A. axis shaft, the farther away from the back of the shaft
that you are the more accurate you will be (Fig.i3). Even though the
true celestial pole may be up to twice the moon's diameter away
(Polaris circles the pole once a day) you won't find this a problem
unless you are doing long exposure photography.

After a while you will notice your target drifting slowly North or South
depending on the direction of the pole relative to Polaris. To keep the
target in the center of the view, turn only the R.A. slow-motion cable.
After your telescope is polar aligned, no further adjustments in the
azimuth and latitude of the mount should be made in the observing
session, nor should you move the tripod. Only movements in R.A.
and DEC axis should be made in order to keep an object in the field.

Southern Hemisphere

In the Southern Hemisphere you must align the mount to the SCP by
locating its position with star patterns, without the convenience of a
nearby bright star. The closest star is the faint 5.5-mag. Sigma
Octanis which is about one degree away. Two sets of pointers which
help to locate the SCP are alpha and beta Crucis (in the Southern
Cross) and a pointer running at a right angle to a line connecting
alpha and beta Centauri (Fig.i4).

Polaris

Cassiopeia

Fig.i2

Fig.i3

+

NCP

Polaris

Little Dipper

racking celestial objects

T

When observing through a telescope, astronomical objects
appear to move slowly through the telescope's field of view.
When the mount is correctly polar aligned, you only need to
turn the R.A. slow-motion to follow or track objects as they
move through the field. The DEC. slow-motion control is not
needed for tracking. A R.A. motor drive can be added to
automatically track celestial objects by counteracting the
rotation of the Earth. The rotation speed of the R.A. drive
matches the Earth's rotation rate for stars to appear
stationary in the telescope eyepiece. Different tracking
speeds are also available in some models. A second drive
can be added to give DEC control which is very useful for
doing astrophotography.

omeg

Octanis

a

SCP +

Fig.i4

alpha
Centauri

beta
Centauri

beta
Crucis

alpha
Crucis

13

sing the setting circles

U

The quickest way to find objects is to learn the Constellations
and use the finderscope, but if the object is too faint you may
want to use setting circles on an equatorial mount. Setting
circles enable you to locate celestial objects whose celestial
co-ordinates have been determined from star charts. Your
telescope must be Polar aligned and the R.A. setting circle
must be calibrated before using the setting circles.

Reading the R.A. setting circle

Setscrew

0

2

4

6

8

10

9

10

11

14

13

12

13

11

6

8

7

6

16

15

7

17

5

18

4

8

19

20

9

Pointer

R.A. Setting Circle

Date circle

The telescope's R.A. setting circle is scaled in hours, from 1
through 24, with small lines in between representing 10
minute increments. The upper set of numbers apply to
viewing in the Northern Hemisphere, while the numbers
below them apply to viewing in the Southern Hemisphere.
The section next to the set crew is scaled in minutes, from 1
through 10, representing the exact minute within the 10
minute increments.

In the case of Fig.j, the R.A. setting circle pointer indicates
approximately 8 hours and 20 minutes. Now look for the
number in the minute scale that aligns with any line on the
main R.A. setting circle. In this case, it is 1. The reading on
this R.A. setting circle, therefore, is 8 hours and 21 minutes.

Setting (calibrating) the R.A. setting circle

In order to set your Right Ascension circle you must first find
a star in your field of view with known coordinates. A good
one would be the 0.0 magnitude star Vega in the
Constellation Lyra. From a star chart we know the R.A.
coordinate of Vega is 18h 36m. Loosen the R.A. and DEC.
lock knobs on the mount and adjust the telescope so that
Vega is centred in the field of view of the eyepiece. Tighten
the R.A. and DEC. lock knobs to lock the mount in place.
Now rotate the R.A. setting circle until it reads 18h36m. You
are now ready to use the setting circles to find objects in the
sky.

Finding objects using the setting circles

Polarscope holder

Polarscope
alignment screw

Fig.j

1 minute

+

0

2

4

6

8

10

8 hours and 20 minutes
(Northern Hemisphere)

10

11

15

14

13

12

13

11

7

6

7

6

16

17

5

18

4

8

19

20

9

=

8 hours and 21 minutes

8

9

15 hours and 40 minutes

-

1 minute

=

15 hours and 39 minutes

(Southern Hemisphere)

Example: Finding the faint planetary nebula M57; "The Ring"

From a star chart, we know the coordinates of the Ring are Dec. 33º and R.A. 18h52m. Unlock the DEC lock knob
and rotate your telescope in DEC until the pointer on the DEC setting circle reads 33º. Re-tighten the DEC lock
knob. Loosen the R.A. lock knob and rotate the telescope in R.A. until the pointer on the R.A. setting circle reads
18h52m (do not move the R.A. circle). Re-tighten the R.A. lock knob. Now look through the Red Dot Finder to see
if you have found M57. Adjust the telescope with R.A. and DEC. flexible cables until M57 is centred in the Red
Dot Finder. Now look through the telescope using a low power eyepiece. Centre M57 in the field of view of the
eyepiece.

If you are familiar with the night sky, it is sometimes convenient to find an object using only the DEC coordinate.
Loosen the DEC. lock knob and rotate the telescope in DEC. until the pointer on the DEC setting circle reads 33º.
Re-tighten the DEC. lock knob. Now traverse through Lyra in R.A. axis until M57 appeares in the field of view.

The setting circles will get you close to the object you wish to observe, but are not accurate enough to put it in the
centre of your Red Dot Finder's field of view. The accuracy of your setting circles also depends on how accurate
your telescope is polar aligned.

14

sing the polarscope (optional)

U

The Polar Alignment Finderscope or 'polarscope' gives Northern Hemisphere users a convenient tool for pointing
at the NCP. It has a large circle circumscribing the path of Polaris, with the NCP located at the crosshair, and it
has a smaller circle to indicate the direction of Polaris. However, the Earth rotates and the orientation of the stars
changes, so a method is needed to obtain the correct alignment of Polaris in the polarscope, for the date and
time of your viewing session.

Aligning the polarscope to the mount's polar axis:

This is most easily done by pointing at a terrestrial
target with the RA drive turned off. To allow full rotation
around the RA axis, remove the telescope and the
counterweight, including the rod. Unlock the Dec
clutch and rotate to Dec 0°, then lock the Dec clutch.
Remove the cap from the bottom of the RA axis shaft
and the plug from the top (Fig.k, EQ5 shown here).

At the bottom of the polar shaft is a black, 24-hour
clock dial. The top row of numbers is for Northern
Hemisphere use, the lower for the Southern
Hemisphere. Unlock the setscrew just above it and
rotate the dial until zero is aligned with the indicator
cast into the metal just below the screw. Tighten the
setscrew to lock the dial (Fig.k1).

The silver dial just below it is a calendar dial. The
months are numbered 1-12. The longest lines
separate the months, the middle-length lines are ten
days apart, and the short lines between them are two
days apart.

The black collar holding this silver dial in place, has an
indicator line inscribed on it. The numbers nearest this
collar are marked "E 20 10 0 10 20 W". These will be
explained later, but for now rotate the silver dial until
the middle zero is aligned with the indicator line on the
black collar.

At midnight on November 1, on the Central Meridian of
your local time zone, Polaris is directly above the NCP.
It is therefore directly below when viewed through the
inverted view of the polarscope. This provides a good
way to orient the polarscope in the mount.

Unlock the R.A. clutch and rotate the mount in R.A.
until 'November 1' (long line between 10 and 11) on
the calendar dial is lined up with '0' (midnight) on the
24-hour clock dial, then lock the clutch again (Fig.k2).
Loosen the three polarscope alignment screws.

Look into the polarscope and you will see the Polaris
Location Indicator diagram. Locate a smaller circle
(Polaris written next to it) off on the big circle (Fig.k3).
Turn the polarscope until the little offset circle is at the
bottom and then slide it into the polarscope holder,
lined up with the zero on the clock dial. Insert the
polarscope far enough so that later it will not interfere
with the protective cap.

Dec lock knob

Fig.k

Dec dial

Fig.k1

4

20

Fig.k2

8

10

2

3

22

21

4

20

9

8

R.A. lock knob

Setscrew

0

2

4

6

8

10

23

1

2

3

22

21

11

10

0

23

12

10

20

E

22

21

1

2

20

3

1

0

10

20

4

2

W

Indicator

24 hour clock

Date circle

Meridian Offset

Indicator

Polarscope holder

Polarscope
alignment screw

Polarscope

Setscrew

0

2

4

6

1
23

23

0

10

22

21

1

2

20

3

11

4

12

E

20

10

0

Indicator

Time: 24:00 (midnight)

Date: November 1

Polarscope holder

Polarscope
alignment screw

Polarscope

C

a

s

s

i

o

p

e

i

a

Fig.k3

CP

N

s

n
a

ct

s

O

ri
la
o
P

r

e

p

p

i

D

g

i

B

15

Once you have it inserted you will have to centre it. The easiest way to do this is to lower the mount head in
azimuth and sight on a distant object in daylight. This may involve taking out the latitude t-screw, shortening one
leg, or both to get the head down low enough. After you have done this unlock the R.A. clutch again and rotate
the mount back and forth in R.A. while keeping your target in view. The idea is to gently tweak the three alignment
screws, while rotating the mount, until the target remains at the centre of rotation. This shouldn't take long and
after that keep the plastic cap on to protect it from getting bumped off alignment. Set the azimuth of the mount
back to the correct latitude.

Using the polarscope:

1)

Now about the numbers "E 20 10 0 10 20 W". First, you need to
find your present Longitude. You can do this by consulting a map,
chart, GPS, etc. The idea is to find how far east or west your
viewing site is from the reference meridian for your time zone. For
example, the Longitude of Vancouver, BC is 123° and the
reference meridian for the Pacific Time Zone is 120°, so the
setting will be 3° W. The lines on the dial are 5° apart so rotate the
silver dial until the indicator on the black collar points between the
zero and 5° line (Fig.l). If you observe from a significantly different
longitude, this setting will have to be changed.

At your viewing site, set the mount (without weights and scope) facing North. Adjust it to a convenient height

2)
for viewing and carefully level it. Unlock the Dec clutch and rotate to Dec 0°, then lock the Dec clutch. Remove
the cap from the bottom of the RA axis shaft and the plug from the top.

Set the 24-hour clock dial so that the hour '0' aligns with the top indicator, and lock it in place with the

3)
setscrew. Remember this dial is a clock face running from 0-23 hours. Northern hemisphere users use the top
row of numbers and all times are in Standard Time. Do not use Daylight Saving Time for the following setting.

Unlock the R.A. clutch, and rotate the mount in R.A. until the current date on the silver calendar dial, is aligned

4)
with the current time using the black 24-hour clock dial (Standard Time), then lock the R.A. clutch.

5)

Using only the latitude adjustment t-screws for up and down, and the azimuth adjustment off-set screws on the
north side of your mount for left-right, centre Polaris in the little offset circle. You may have to shine your red
flashlight at an angle across the front to illuminate the crosshair or better yet have a friend hold the light while
you do the adjustments.

Fig.l

E 20 10 0 10 20 W

Lastly, loosen the top setscrew, unlock the R.A. clutch, put on the counterweights and then the scope and

6)
finally adjust the balance position of the counterweight.

16

our Te

ointing

P

A German Equatorial mount has an adjustment, sometimes called a wedge, which tilts the mount's polar axis so
that it points at the appropriate Celestial Pole (NCP or SCP). Once the mount has been polar aligned, it needs to
be rotated around only the polar axis to keep an object centred. Do not reposition the mount base or change the
latitude setting. The mount has already been correctly aligned for your geographical location (i.e. Latitude), and all
remaining telescope pointing is done by rotating the optical tube around the polar (R.A.) and declination axes.

A problem for many beginners is recognizing that a polar-aligned, equatorial mount acts like an alt-azimuth mount
which has been aligned to a celestial pole. The wedge tilts the mount to an angle equal to the observer's Latitude,
and therefore it swivels around a plane which parallels the celestial (and Earth's) equator (Fig.m). This is now its
"horizon"; but remember that part of the new horizon is usually blocked by the Earth. This new "azimuth" motion is
called Right Ascension (R.A). In addition, the mount swivels North(+) and South(-) from the Celestial Equator
towards the celestial poles. This plus or minus "altitude" from the celestial equator is called Declination (Dec).

Y

lescope

Right
Ascension

Meridian

Line

Fig.m

Equatorial Mount

(Northern Hemisphere)

Zenith

Mount aligned on
North Celestial Pole

Object you
are viewing

Polaris

Declination

Latitude

W

N

S

Plane of local horizon

Nadir

E

Apparent
movement
of stars

Plane of Celestial
Equator

17

Fig.n

1.

Celestial Pole

+

2.

3.

Pointing to the NCP

For the following examples, it is assumed that
the observing site is in the Northern
Hemisphere. In the first case (Fig.n2), the
optical tube is pointing to the NCP. This is its
probable position following the polar-alignment
step. Since the telescope is pointing parallel to
the polar axis, it still points to the NCP as it is
rotated around that axis counter-clockwise,
(Fig.n1) or clockwise (Fig.n3).

Pointing toward the western or eastern
horizon

Now, consider pointing the telescope to the
western (Fig.o1) or eastern (Fig.o2) horizon. If
the counterweight is pointing North, the
telescope can be swivelled from one horizon
to the other around the Dec axis in an arc that
passes through the NCP (any Dec arc will
pass through the NCP if the mount is
polar-aligned). It can be seen then that if the
optical tube needs to be pointed at an object
north or south of this arc, it has to be also
rotated around the R.A. axis.

Fig.o

Celestial

Pole

+

1.

Telescope pointing West
Counterweight pointing North

2.

Telescope pointing East
Counterweight pointing North

18

Rotation of the R.A. axis

Rotation of the Dec. axis

Fig.p

Examples of the telescope moved in R.A. and Dec

1.

Fig.q

Telescope pointing South

2.

Pointing to directions other than due North

Pointing in any direction other than due North
requires a combination of R.A. and Dec
positions (Fig.p). This can be visualized as a
series of Dec arcs, each resulting from the
position of rotation of the R.A. axis. In practice
however, the telescope is usually pointed, with
the aid of a finderscope, by loosening both the
R.A. and Dec locks and swivelling the mount
around both axes until the object is centred in
the eyepiece field. The swivelling is best done
by placing one hand on the optical tube and the
other on the counter-weight bar, so that the
movement around both axes is smooth, and no
extra lateral force is applied to the
axis-bearings. When the object is centred,
make sure the R.A and Dec locks are both
re-tightened to hold the object in the field and
allow tracking by adjusting only in R.A.

Pointing at an object

Pointing at an object, for example to the South
(Fig.q), can often be achieved with the optical
tube positioned on either side of the mount.
When there is a choice of sides, particularly
when there could be a long observing period,
the East side (Fig.q2) should be chosen in the
Northern Hemisphere because tracking in R.A.
will move it away from the mount's legs. This is
particularly important when using an R.A motor,
because if the optical tube jambs against the
mount's legs, it can result in damage to the
motor and/or the gears.

19

Telescopes with long focal lengths often
have a "blind spot" when pointing near the
zenith, because the eyepiece-end of the
optical tube bumps into the mount's legs
(Fig.r1). To adapt for this, the optical tube
can be very carefully slipped up inside the
tube rings (Fig.r2). This can be done safely
because the tube is pointing almost
vertically, and therefore moving it does not
cause a Dec-balance problem. It is very
important to move the tube back to the
Dec-balanced position before observing
other sky areas.

Something which can be a problem is that
the optical tube often rotates so that the
eyepiece, finderscope and the focussing
knobs are in less convenient positions.
The diagonal can be rotated to adjust the
eyepiece. However, to adjust the positions
of the finderscope and focussing knobs,
loosen the tube rings holding the optical
tube and gently rotate it. Do this when you
are going to view an area for while, but it is
inconvenient to do every time you briefly
go to a new area.

1.

2.

Finally, there are a few things to consider
to ensure that you are comfortable during
the viewing session. First is setting the
height of the mount above the ground by
adjusting the tripod legs. You must
consider the height that you want your
eyepiece to be, and if possible plan on
sitting on a comfortable chair or stool. Very
long optical tubes need to be mounted
higher or you will end up crouching or lying
on the ground when looking at objects
near the zenith. On the other hand, a short
optical tube can be mounted lower so that
there is less movement due to vibration
sources, such as wind. This is something
that should be decided before going
through the effort of polar aligning the
mount.

Fig.r

Telescope pointing at the Zenith

20

ce

ie

hoosing the appropriate ey

C

Calculating the magnification (power)

The magnification produced by a telescope is determined by the focal length of the eyepiece that is used with it.
To determine a magnification for your telescope, divide its focal length by the focal length of the eyepieces you
are going to use. For example, a 10mm focal length eyepiece will give 80X magnification with an 800mm focal
length telescope.

ep

magnification =

When you are looking at astronomical objects, you are looking through a column of air that reaches to the edge
of space and that column seldom stays still. Similarly, when viewing over land you are often looking through heat
waves radiating from the ground, house, buildings, etc. Your telescope may be able to give very high
magnification but what you end up magnifying is all the turbulence between the telescope and the subject. A
good rule of thumb is that the usable magnification of a telescope is about 2X per mm of aperture under good
conditions.

Calculating the field of view

The size of the view that you see through your telescope is called the true (or actual) field of view and it is
determined by the design of the eyepiece. Every eyepiece has a value, called the apparent field of view, which is
supplied by the manufacturer. Field of view is usually measured in degrees and/or arc-minutes (there are 60
arc-minutes in a degree). The true field of view produced by your telescope is calculated by dividing the
eyepiece's apparent field of view by the magnification that you previously calculated for the combination. Using
the figures in the previous magnification example, if your 10mm eyepiece has an apparent field of view of 52
degrees, then the true field of view is 0.65 degrees or 39 arc-minutes.

True Field of View =

To put this in perspective, the moon is about 0.5° or 30 arc-minutes in diameter, so this combination would be fine
for viewing the whole moon with a little room to spare. Remember, too much magnification and too small a field of
view can make it very hard to find things. It is usually best to start at a lower magnification with its wider field and
then increase the magnification when you have found what you are looking for. First find the moon then look at
the shadows in the craters!

Focal length of the telescope

Focal length of the eyepiece

Apparent Field of View

=

Magnification

=

800mm

10mm

52°

80X

=

=

80X

0.65°

Calculating the exit pupil

The Exit Pupil is the diameter (in mm) of the narrowest point of the cone of light leaving your telescope. Knowing
this value for a telescope-eyepiece combination tells you whether your eye is receiving all of the light that your
primary lens or mirror is providing. The average person has a fully dilated pupil diameter of about 7mm. This
value varies a bit from person to person, is less until your eyes become fully dark adapted and decreases as you
get older. To determine an exit pupil, you divide the diameter of the primary of your telescope (in mm) by the
magnification.

Diameter of Primary mirror in mm

Exit Pupil =

For example, a 200mm f/5 telescope with a 40mm eyepiece produces a magnification of 25x and an exit pupil of
8mm. This combination can probably be used by a young person but would not be of much value to a senior
citizen. The same telescope used with a 32mm eyepiece gives a magnification of about 31x and an exit pupil of

6.4mm which should be fine for most dark adapted eyes. In contrast, a 200mm f/10 telescope with the 40mm

eyepiece gives a magnification of 50x and an exit pupil of 4mm, which is fine for everyone.

Magnification

21

OBSERVING THE SKY

ky conditions

S

Sky conditions are usually defined by two atmospheric characteristics, seeing, or the steadiness of the air, and
transparency, light scattering due to the amount of water vapor and particulate material in the air. When you
observe the Moon and the planets, and they appear as though water is running over them, you probably have
bad "seeing" because you are observing through turbulent air. In conditions of good "seeing", the stars appear
steady, without twinkling, when you look at them with unassisted eyes (without a telescope). Ideal "transparency"
is when the sky is inky black and the air is unpolluted.

ving site

ng an obs

ti

ec

el

S

Travel to the best site that is reasonably accessible. It should be away from city lights, and upwind from any
source of air pollution. Always choose as high an elevation as possible; this will get you above some of the lights
and pollution and will ensure that you aren't in any ground fog. Sometimes low fog banks help to block light
pollution if you get above them. Try to have a dark, unobstructed view of the horizon, especially the southern
horizon if you are in the Northern Hemisphere and vice versa. However, remember that the darkest sky is usually
at the "Zenith", directly above your head. It is the shortest path through the atmosphere. Do not try to observe any
object when the light path passes near any protrusion on the ground. Even extremely light winds can cause major
air turbulence as they flow over the top of a building or wall.

er

Observing through a window is not recommended because the window glass will distort images considerably.
And an open window can be even worse, because warmer indoor air will escape out the window, causing
turbulence which also affects images. Astronomy is an outdoor activity.

ve

er

obs

hoosing the

C

The best conditions will have still air, and obviously, a clear view of the sky. It is not necessary that the sky be
cloud-free. Often broken cloud conditions provide excellent seeing. Do not view immediately after sunset. After
the sun goes down, the Earth is still cooling, causing air turbulence. As the night goes on, not only will seeing
improve, but air pollution and ground lights will often diminish. Some of the best observing time is often in the
early morning hours. Objects are best observed as they cross the meridian, which is an imaginary line that runs
through the Zenith, due North-South. This is the point at which objects reach their highest points in the sky.
Observing at this time reduces bad atmospheric effects. When observing near the horizon, you look through lots
of atmosphere, complete with turbulence, dust particles and increased light pollution.

ooling the telescope

C

Telescopes require at least 10 to 30 minutes to cool down to outside air temperature. This may take longer if
there is a big difference between the temperature of the telescope and the outside air. This minimizes heat wave
distortion inside telescope tube (tube currents). Allow a longer cooling time for larger optics. If you are using an
equatorial mount, use this time for polar alignment.

best time

to

ur eyes

yo

ing

dapt

A

Do not expose your eyes to anything except red light for 30 minutes prior to observing. This allows your pupils to
expand to their maximum diameter and build up the levels of optical pigments, which are rapidly lost if exposed to
bright light. It is important to observe with both eyes open. This avoids fatigue at the eyepiece. If you find this too
distracting, cover the non-used eye with your hand or an eye patch. Use averted vision on faint objects: The
center of your eye is the least sensitive to low light levels. When viewing a faint object, don't look directly at it.
Instead, look slightly to the side, and the object will appear brighter.

22

PROPER CARE FOR YOUR TELESCOPE

ollimating a Newtonian reflector

C

Collimation is the process of aligning the mirrors of
your telescope so that they work in concert with
each other to deliver properly focused light to your
eyepiece. By observing out-of-focus star images,
you can test whether your telescope's optics are
aligned. Place a star in the centre of the field of
view and move the focuser so that the image is
slightly out of focus. If the seeing conditions are
good, you will see a central circle of light (the Airy
disc) surrounded by a number of diffraction rings. If
the rings are symmetrical about the Airy disc, the
telescope's optics are correctly collimated (Fig.s).

If you do not have a collimating tool, we suggest
that you make a "collimating cap" out of a plastic
35mm film canister (black with gray lid). Drill or
punch a small pinhole in the exact center of the lid
and cut off the bottom of the canister. This device
will keep your eye centered of the focuser tube.
Insert the collimating cap into the focuser in place
of a regular eyepiece.

Fig.s

Fig.s1

Fig.s2

Correctly aligned

Primary mirror

Needs collimation

Focuser

Support for
secondary mirror

Secondary mirror

Primary
mirror

Collimation is a painless process and works like
this:

Pull off the lens cap which covers the front of the
telescope and look down the optical tube. At the
bottom you will see the primary mirror held in place
by three clips 120º apart, and at the top the small
oval secondary mirror held in a support and tilted
45º toward the focuser outside the tube wall
(Fig.s1).

The secondary mirror is aligned by adjusting the
three smaller screws surrounding the central bolt.
The primary mirror is adjusted by the three
adjusting screws at the back of your scope. The
three locking screws beside them serve to hold the
mirror in place after collimation. (Fig.s2)

Aligning the Secondary Mirror

Point the telescope at a lit wall and insert the
collimating cap into the focuser in place of a regular
eyepiece. Look into the focuser through your
collimating cap. You may have to twist the focus
knob a few turns until the reflected image of the
focuser is out of your view. Note: keep your eye
against the back of the focus tube if collimating
without a collimating cap. Ignore the reflected
image of the collimating cap or your eye for now,
instead look for the three clips holding the primary
mirror in place. If you can't see them (Fig.s3), it
means that you will have to adjust the three bolts
on the top of the secondary mirror holder, with
possibly an Allen wrench or Phillip's screwdriver.

Locking screw

Fig.s3

Primary mirror clip

Fig.s4

Primary mirror clip

Adjusting screw

Ignore the reflected
image for now

Primary mirror clip

Mirror cell

Primary mirror clip

23

You will have to alternately loosen one and then compensate for the slack by tightening the other two. Stop when
you see all three mirror clips (Fig.s4). Make sure that all three small alignment screws are tightened to secure the
secondary mirror in place.

Aligning the Primary Mirror

Find the three locking screws at the back of your telescope and loosen them by a few turns.

Adjusting screw Locking screw

If you see 3 large nuts protruding
from the back of your telescope
and 3 small Phillip's-head screws
besides them, the Phillip's-head
screws are the locking screws
and the large nuts are the
adjusting screws.

Hex bolt (Locking screw)

Adjusting screw

If you see 3 hex bolts and 3 Phillip's head screws, the hex bolts are
the locking screws and the Phillip's-head screws are the adjusting
screws. You will need an Allen wrench to adjust the locking screws.

Now run your hand around the front of your
telescope keeping your eye to the focuser, you
will see the reflected image of your hand. The
idea here being to see which way the primary
mirror is defected, you do this by stopping at the
point where the reflected image of the secondary
mirror is closest to the primary mirrors' edge
(Fig.s5).

Locking screw

Fig.s5

Secondary
mirror

Adjusting screw

If you see 6 Phillip's-head
screws but 3 protruding from
the back of your telescope, the
3 protruding screws are
locking screws and the ones
next to them are adjusting
screws.

When you get to that point, stop and keep your
hand there while looking at the back end of your
telescope, is there an adjusting screw there? If
there is you will want to loosen it (turn the screw
to the left) to bring the mirror away from that
point. If there isn't an adjusting screw there, then
go across to the other side and tighten the
adjusting screw on the other side. This will
gradually bring the mirror into line until it looks
like Fig.s6. (It helps to have a friend to help for
primary mirror collimation. Have your partner
adjust the adjusting screws according to your
directions while you look in the focuser.)

After dark go out and point your telescope at
Polaris, the North Star. With an eyepiece in the
focuser, take the image out of focus. You will see
the same image only now, it will be illuminated by
starlight. If necessary, repeat the collimating
process only keep the star centered while
tweaking the mirror.

24

Primary mirror

Fig.s6

Both mirrors aligned
with collimating cap in

Stop and keep your
hand here

Both mirrors aligned with
eye looking in focuser

ollimating a refractor with the adjustable objective-lens cel

C

Collimation is the process of aligning the lenses of your telescope so
that the light they collect will focus at the right spot at the back of
your telescope for your eyepieces to work.

Collimation is a simple process and works like this:

Pull off the dew cap at the front of your telescope and look into the
scope. The pair of lenses are held in a cell by a threaded ring. This
cell is held in place by three pairs of screws spaced 120 degrees
apart. The larger Phillip's head screws actually hold the cell on, while
the smaller, buried Allen screws push against a ledge at the front of
the tube and allow the cell to tilt slightly, by tension against the
Phillips screws (Fig.t). The idea being to alternately loosen and
tighten each against the other until you have a round star image.

There are a number of devices available for collimation. One of the
best is your eyepiece and Polaris. (See Fig.h for the location of
Polaris.) For this purpose it is best that your telescope not be polar
aligned, in fact point the mount head due east or west. This is
because German Equatorial Mounts can have a small blind spot near
the pole. Also turn off the motor drive if you have one attached to the
mount.

Use your lowest power (largest number eyepiece) to acquire Polaris,
centre it using your slow motion controls. Now switch to your next
higher power eyepiece, while keeping the image centred. The
in-focus star image will have a bright innermost point, a slightly
fainter inner ring and a fainter still outer ring that is hard to see
(Fig.t1). If it doesn't look like this, or you can't reach focus then start
with: take out your star diagonal and look at the image slightly out of
focus, this will allow you to gauge the deflection. A typical
off-collimation image will have a bright spot off to one side when you
bring the focus out (Fig.t2).

Fig.t

Fig.t1

Fig.t2

l

Correctly aligned

The actual process is to slightly loosen the pair on the side the
deflection is, slacken the Allen head screws then tighten the Phillip's
head screws against them again. Check the star image again after
moving it into the centre of the eyepiece. If you find your image
getting worse, then go the other way, or slacken the other two Allen
screws a little. Once you have a round star image you are set. It
helps to have a friend to help with the collimation. Have your partner
adjust the screws according to your directions while you look in the
eyepiece.

leaning your telescope

C

Replace the dust cap over the end of the telescope whenever it is not in use. This prevents dust from settling on
the mirror or lens surfaces. Do not clean the mirror or lens unless you are familiar with optical surfaces. Clean the
finderscope and eyepieces with special lens paper only. Eyepieces should be handled with care, avoid touching
optical surfaces.

Needs collimation

25

APPENDIX A – STANDARD TIME ZONES OF THE WORLD

26

APPENDIX B – OPTIONAL ACCESSORIES

LONG EYE-RELIEF EYEPIECES

These multi-coated eyepieces provide a generous
20mm eye relief, and all focal lengths including the
2mm model feature particularly wide diameter eye
lenses for maximum viewing comfort. These
eyepieces are especially valuable for spectacle
wearers, as the long eye relief allows the entire field
to be viewed whilst spectacles are being worn. Soft
rubber eyecups are provided for added comfort and
to keep out extraneous light.

Available in: 25mm (50º apparent field), 20mm (50º
apparent field), 15mm (50º apparent field), 10mm
(50º apparent field), 9mm (50º apparent field), 5mm
(45º apparent field), 2mm (45º apparent field).

WIDE-ANGLE EYEPIECES

These ultra-wide angle, multi-Coated eyepieces
offer a generous 66º apparent field of view, allowing
more sky objects to be viewed at one time. They
provide sharp images right across the field. Rubber
eyepieces are included for viewing comfort and to
exclude extraneous light.

Available in: 20mm (18mm Eye Relief), 15mm
(13mm Eye Relief), 9mm (15mm Eye Relief), 6mm
(14.8mm Eye Relief).

2" EYEPIECES

These 2"/50.8mm fully multi-coated eyepieces offer
exceptional value for the money. They feature long
eye relief, a wide field of view and soft rubber
eyecups. The multi-coatings ensure maximum light
transmission and enhance image contrast.

Available in: 42mm (50º apparent field), 35mm (56º
apparent field), 28mm (56º apparent field).

*To be used with telescopes with a 2" focuser.

2" 90º STAR DIAGONAL

Made to yield maximum astronomical viewing
performance, the 2"/50.8mm star diagonal is perfect
with telescopes with a 2" focuser and 2" eyepieces.
It comes with a 1.25" adapter to accept standard

1.25" eyepieces.

*To be used with telescopes with a 2" focuser.

27

APPENDIX C – RECOMMENDED READING

mateur Astronom

A

Beginner's Guide to Amateur Astronomy: An
Owner's Manual for the Night Sky by David J. Eicher
and, Michael Emmerich (Kalmbach Publishing Co.,
Books Division, Waukesha, WI, 1993).

NightWatch: A Practical Guide to Viewing the
Universe by Terence Dickinson, (Firefly Books,
Willowdale, ON, Canada, 3rd edition, 1999).

Star Testing Astronomical Telescopes by Harold
Richard Suiter, (Willmann-Bell, Inc., Richmond, VA,

1994).

Star Ware: The Amateur Astronomer's Ultimate
Guide to Choosing, Buying, and Using Telescopes
and Accessories by Philip S. Harrington (John Wiley
& Sons, New York, 1998 ).

The Backyard Astronomer's Guide by Terence
Dickinson and Alan Dyer (Firefly Books Ltd.,
Willowdale, ON, Canada, revised edition, 1994).

y

hotograp

-p

ro

st

A

The Great Atlas of the Stars by Serge Brunier,
Constellation photography by Akira Fujii (Firefly
Books; Willowdale, ON, Canada 2001).

A Manual Of Advanced Celestial Photography by
Brad D. Wallis and Robert W. Provin (Cambridge
University Press; New York; 1984).

Astrophotography An Introduction by H.J.P. Arnold
(Sky Publishing Corp., Cambridge, MA,Sky &
Telescope Observer's Guides Series, ed. Leif J.
Robinson, 1995).

Astrophotography for the Amateur by Michael
Covington (Cambridge University Press, Cambridge,
UK, 2nd edition,1999).

Splendors of the Universe: A Practical Guide to
Photographing the Night Sky by Terence Dickinson
and Jack Newton (Firefly Books, Willowdale, ON,
Canada, 1997).

hy

The Beginner's Observing Guide: An Introduction to
the Night Sky for the Novice Stargazer by Leo
Enright, (The Royal Astronomical Society of
Canada, Toronto, ON, Canada, 1999).

The Deep Sky: An Introduction by Philip S.
Harrington (Sky Publishing Corporation, Cambridge,
MA, Sky & Telescope Observer's Guides Series, ed.
Leif J. Robinson, 1997).

The Universe from Your Backyard: A Guide to Deep
Sky Objects by David J. Eicher (Kalmbach
Publishing Co., Books Division, Waukesha, WI,

1988).

Turn Left at Orion: A Hundred Night Sky Objects to
See in a Small Telescope--and how to Find Them by
Guy J. Consolmagno and Dan M. Davis, (Cambridge
University Press, New York, 3rd edition, 2000)

Wide-Field Astrophotography by Robert Reeves
(Willmann-Bell, Inc., Richmond, VA, 2000).

tional

bser

O

A Field Guide to the Stars and Planets by Jay M.
Pasachoff, (Houghton Mifflin Company, 1999).

Atlas of the Moon by Antonín Rükl (Kalmbach
Publishing Co., Books Division, Waukesha, WI,

1993).

Burnham's Celestial Handbook: An Observer's
Guide to the Universe Beyond the Solar System by
Robert Burnham (Dover Publications, New York; 3­volume set, 1978).

Observer's Handbook by The Royal Astronomical
Society of Canada, (University of Toronto Press,
Toronto, ON, Canada, published annually).

va

References

28

Sky Atlas 2000.0 by Wil Tirion and Roger W. Sinnott
(Sky Publishing Corp., Cambridge, MA, 2nd edition,

1998).

APPENDIX D – GLOSSARY

A

bsolute Magnitude

The apparent brightness a star would have if placed
at a distance of 10 parsecs from the earth.

Achromatic Lens

A refractor lens, made of two or sometimes three
separate lenses, which has the effect of bringing
most of the viewed colors to a sharp focus, thus
reducing chromatic aberration.

Alt-azimuth

A simple mount that allows movement in altitude (up
and down) and in azimuth (side to side).

Anti-reflection Coating

A thin layer of film applied to an optical surface that
reduces the loss of transmission of light.

Aperture

The diameter of the primary mirror or lens.

arlow Lens

B

A “negative” lens which, when placed in front of the
eyepiece, increases the focal length and
magnification and decreases the field.

C

ollimation

The process of aligning all the elements of an optical
system. Collimation is routinely needed in reflectors,
often in Catadioptric systems but seldom in
refractors.

eclination

D

Similar to Latitude on the Earth’s surface, it is the
distance in degrees North or South of the Celestial
Equator (the projection of the Earth’s Equator onto
the Celestial Sphere). The degrees can be
sub-divided into minutes and seconds.

Dew Cap

A tube extending forward from the front lens of a
telescope. It prevents dew from forming on the lens
as it cools down, and acts as a sunshade to reduce
reflections during the day.

Diagonal

A mirror or prism system which changes the angle
and orientation of the light rays coming from the
telescope to the eyepiece.

Eyepiece

Also called an ocular. This is a small tube that
contains the lenses needed to bring a telescope's
focus to a final image in the eye. Telescopes usually
come with at least two eyepieces: one for low power
and a second for a higher power view.

Eye Relief

The distance between the eyepiece lens and the
position in which the eye must be placed to see
through the telescope. Telescope users who wear
eyeglasses while observing, appreciate the benefits
of longer eye relief.

Exit Pupil

This is the diameter of the beam of light from the
eyepiece which reaches the pupil of the eye. It is
usually expressed in mm, and determined by dividing
the diameter of the primary (in mm) by the
Magnification. Knowing this value and the diameter
of your dilated pupil allows you to choose the
eyepieces which will work best for you with a specific
telescope.

ield of View

F

The maximum view angle of an optical instrument.
The number, in degrees, supplied by the
manufacturer is the Apparent Field of View. To find
the True Field of View (also known as the Actual
Field of View), divide the Apparent Field of View by
the Magnification.

Finderscope

A low power telescope attached parallel to the main
instrument which provides easy object locating and
telescope aiming.

Focal Length

The distance of the light path from the objective
(primary lens or mirror) to the convergence of the
beam. The convergent spot is called the Focus or
Focal Point.

Focal Ratio

This is found by dividing an optical system’s Focal
Length by its Aperture. The resulting value is
sometimes called the system’s “speed”.

Focuser

A device which brings the light rays in a telescope to
a precise focus. Common designs include geared
(rack-and-pinion), gearless (Crayford-style) and
helical.

E

quatorial Mount

A telescope mount with an axis parallel to the axis of
the earth. This provides easy tracking of sky objects
and for photography when combined with a clock
drive.

ens

L

A transparent optical element consisting of one or
more pieces of glass. A lens has curved surfaces
that bring distant light to a focus.

29

agnifying Power

M

etting Circles

S

The amount by which a system increases the
apparent size of objects. Magnification is determined
by dividing the Focal Length of the telescope by the
Focal Length of the eyepiece.

Mirror

In a telescope, it is a highly polished surface made
to reflect light. Primary mirrors are usually made
spherical or paraboloidal (parabolic) to focus the
light rays.

bjective

O

The primary or largest element in an optical system;
sometimes called the "fixed optics."

Optical Tube Assembly

The housing and optical train of a telescope; not
including the mount, diagonal, eyepiece or
accessories.

arabolic Mirror

P

A parabolic or more accurately a "paraboloidal"
mirror, is ground to a shape which brings all
incoming light rays to a perfect focus, on axis.

Circular scales attached to the telescope. They are
marked off in degrees of Declination and hours of
Right Ascension. Together, the circles allow the
position of a known object to be found by setting the
dials to the equatorial coordinates.

rue Field of View

T

How much sky, in angular measure, is available at
the eyepiece. It is contrasted with Apparent Field of
View, which measures the field of the eyepiece
alone.

ide Angle Eyepiece

W

An eyepiece with an Apparent field of view of more
than 50 degrees.

oom Eyepiece

Z

An optical system which provides a variable focal
length.

Polar Axis

A telescope mount's axis that is parallel with the
earth's axis. With a drive motor, the motion of stars
due to the earth's movement can be counteracted so
that they remain in the field.

Power

See Magnifying Power.

Prime Focus

The focal point of the objective mirror or lens.

esolution

R

The ability of an optical system to reveal details.

Resolving Power

The ability of a telescope to separate closely
positioned points.

Right Ascension

Similar to but not the same as Latitude on the
Earth's surface. It is the position eastwards from the
Vernal Equinox, in 24 one-hour units. The hours can
be sub-divided into minutes and seconds.

30

NEVER USE YOUR TELESCOPE TO LOOK DIRECTLY AT THE SUN.
PERMANENT EYE DAMAGE WILL RESULT. USE A PROPER SOLAR FILTER
FIRMLY MOUNTED ON THE FRONT OF THE TELESCOPE FOR VIEWING
THE SUN. WHEN OBSERVING THE SUN, PLACE A DUST CAP OVER YOUR
FINDERSCOPE OR REMOVE IT TO PROTECT YOU FROM ACCIDENTAL
EXPOSURE. NEVER USE AN EYEPIECE-TYPE SOLAR FILTER AND NEVER
USE YOUR TELESCOPE TO PROJECT SUNLIGHT ONTO ANOTHER
SURFACE, THE INTERNAL HEAT BUILD-UP WILL DAMAGE THE
TELESCOPE OPTICAL ELEMENTS.

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