Celestron 21077, 21016, 31027 User Manual

•••• C80-HD Refractor Telescope

•••• C102-HD Refractor Telescope

•••• C114-HD Reflector Telescope

• C150-HD Reflector Telescope

•••• CG-4 Equatorial Mount

Models #21077 / #21016 / #31027 / #31056 / #91510

INSTRUCTION MANUAL

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IDENTIFYING PARTS OF FIGURE 1

1. Star Diagonal (Refractors only) 13. Latitude Scale

2. Eyepiece 14. Altitude Adjustment Screw

3. Finderscope 15. Tripod Mounting Head

4. Finder Bracket 16. Tripod

5. Focuser 17. Tripod Support Brace

6. Tube Rings 18. Counterweight Shaft

7. Objective Cap 19. Counterweight(s)

8. Optical Tube Platform 20. Azimuth Adjustment Screw

9. DEC Setting Circle 21. R.A. Slow Motion Knob

10. R.A. Clamp 22. DEC Clamp

11. R.A. Setting Circle 23. DEC Slow Motion Knob

12. Polar Finder (Optional) 24. Accessory Tray

25. Accessory Tray Mounting Screws

7.

2.

3.

1.

5.

2. 3.

4.

Figure 1A

C80-HD & C102-HD

4.

6.

6.

5.

Figure 1B

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19.

C114-HD & C150-HD

8.

23.

22.

9.

21.

10.

18.

11.

20.

12.

13.

14.

.

15

17.

25.

16.

24.

Figure 1C

CG-4 EQ Mount

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INTRODUCTION

Congratulations on your purchase and welcome to the Celestron world of astronomy. If you’re a newcomer
to the hobby of astronomy, some of the terms and telescope components described in this instruction
manual may be new to you. This manual is designed to instruct you in the proper use of your Celestron C80­HD Refractor, C102-HD Refractor, C114-HD 4.5 Newtonian or C150-HD Newtonian as well as the CG-4
Equatorial Mount. To assist you in assembling and operating your telescope, take time to review this
manual and the parts diagram listed in Figure 1.

WARNING—NEVER LOOK AT THE SUN WITH YOUR TELESCOPE OR ITS FINDERSCOPE.
PERMANENT AND IRREVERSIBLE EYE DAMAGE MAY RESULT AS WELL AS DAMAGE
TO YOUR TELESCOPE.

HOWEVER, YOU MAY ENJOY LOOKING AT THE SUN IF YOU HAVE A SAFE METHOD OF
DOING SO—A SOLAR FILTER. IF USING THE SOLAR FILTER, MAKE SURE THE
FINDERSCOPE IS COVERED.

TELESCOPE ASSEMBLY

The telescopes and all items are packed in one box. Included are:

• Telescope Optical Tube

• German Equatorial Mount

• Adjustable Aluminum Tripod

• 6x30 Finderscope and Bracket

• Counterweight Shaft and Counterweights (3.6 Kg and 1.8 Kg for reflector models #31027, #31056

and refractor model #21016; 3.6 kg only for refractor model #21077 and CG-4 Eq Mount #91510)

• Tripod Accessory Tray

• Declination Slow Motion Knob

• Right Ascension Slow Motion Knob

• 20mm Plossl Eyepiece

• 1 ¼" Mirror Diagonal (Except #31027 & #31056)

Setting Up the Tripod:

1. Locate the tripod head (see figure 1). Attach each leg one by one to the tripod head by aligning the
holes at the top of each leg with the holes in the tripod head. Slide a bolt through each of the legs and
the tripod head and secure at the other end with a wing nut. NOTE: this may have been pre-assembled
at the factory.

2. Now that the tripod legs are attached, stand the tripod up and spread the legs until the center leg
support is fully extended.

3. The equatorial mount, which holds the telescope, attaches to the tripod head. On one side of the tripod
head there is an “N” which signifies North. This side of the tripod will face north when setting up for
an astronomical observing session. Above the “N” is a metal peg about 3/4" high that points straight
up. Place the equatorial mount head on top of the tripod head so that the metal peg fits between the two

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azimuth adjustment bolts. It may be necessary to partially unscrew the bolts to allow the metal peg to
fully extend into the altazimuth housing.

4. Tighten the knob located on the underside of the tripod head. This will hold the equatorial mount
firmly to the tripod head.

Attaching the Accessory Tray

Next, attach the accessory tray to the tripod. Locate the accessory tray and the three wingnut screws to
attach the tray.

1. Place the accessory tray on the center support brace of the tripod and align the holes on the tray with
those on the support brace.

2. Insert the wingnut screws through the bottom of the tripod support brace and thread them into the
accessory tray holes.

With the accessory tray in place, the tripod will be much more stable, making it easier to attach the
telescope.

Installing the Counterweight Bar

With the mount securely in place, you are ready to attach some of the accessories (the telescope
tube will be added last). Start with the Counterweight Bar and Counterweights. Used to balance
the telescope, the Counterweight Bar attaches to the opposite side of the mount as the telescope.
To install the Counterweight Bar:

Retract the counterweight bar lock nut by turning it counterclockwise. This will expose the threads
on the end of the Counterweight Bar.

Thread the Counterweight Bar into the mount completely. It threads into the mount opposite the
telescope.

1. Tighten the lock nut fully for added support.

2. The Counterweight Bar is now installed.

3. Installing the Counterweights

With the counterweight bar in place, you are ready to attach the counterweights.

1. Remove the safety thumbscrew on the end of the counterweight bar.

2. Loosen the counterweight lock screw (on the counterweight itself) so that the central hole

of the counterweight is unobstructed.

3. Slide the counterweight onto the counterweight bar. Move it high enough to allow room

for the second weight (if included).

4. Tighten the counterweight lock screw to hold it in position.

5. Repeat this process for the second weight.

6. Replace the thumbscrew on the end of the counterweight bar. The thumbscrew will

prevent the counterweight(s) from sliding off the bar should they ever become loose.

Attaching the Optical Tube

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Before you attach the optical tube, make sure that the declination and right ascension clamps are
tight. The optical tube attaches to the mount via two rings that are mounted on the tube of the
telescope. To mount the telescope tube:

1. Loosen the knobs on the side of the rings. This will allow you to slide the mounting rings

the length of the optical tube.

2. Locate the two screws on either end of the platform for the optical tube (#8).

3. Hold the telescope up to the mount and slide the mounting rings until they are over the screws on

the mounting platform.

4. Place the flat portion of the ring over the mount so that the hole in the ring is over the screw

protruding out of the mounting platform.

5. Tighten the knobs underneath the mounting platform to secure the rings.

6. Tighten the knobs on the side of the mounting rings to prevent the telescope from sliding

forward or backward. These can be loosened later to reposition the telescope during the
balancing process.

Balancing the Telescope

To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. In
addition, proper balancing is crucial for accurate tracking if using a clock drive. To balance the mount:

1. Release the R.A. Clamp and position the telescope off to one side of the mount (see figure 2a).

2. GRADUALLY release the telescope to see which way it “rolls.”

3. Loosen a counterweight lock screw and slide the counterweight to a point where it balances the
scope (i.e., the telescope remains stationary when the R.A. clamp is released).

4. Tighten the counterweight lock screw.

The scope is properly balanced in right ascension.

Figure 2a Figure 2b

The telescope should also be balanced in declination to prevent any sudden movement when the Declination
clamp is released. To balance the telescope in Declination:

1. Release the R.A. clamp and rotate the telescope so that it is on one side of the mount (i.e., as described
above for balancing the mount in R.A.).

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