CELESTRON 21023 FirstScope 76 Tabletop Telescope User Guide

June 9, 2024
Celestron

21023 FirstScope 76 Tabletop Telescope
User Guide

21023 FirstScope 76 Tabletop Telescope

FirstScope 76 Tabletop Telescope User GuideCELESTRON 21023 FirstScope
76 Tabletop Telescope - fig 1

Verify that all parts are present. Your Cometron FirstScope 76 telescope includes the preassembled base, optical tube, finderscope assembly, and two eyepieces.CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
2To install the fi nderscope, remove the nuts on side of tube, place the finderscope bracket over threaded posts and replace the nuts.CELESTRON
21023 FirstScope 76 Tabletop Telescope - fig 3 Loosen the thumbscrews on the focuser and remove the focuser cap.CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
4 Insert the chrome barrel of the eyepiece into the focuser and secure with setscrews.
CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
5 Remove main telescope lens cap and caps on the fi nderscope. CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
6 Loosen the altitude lock nut by turning it clockwise and hold the bottom of the tube with your other hand. CELESTRON 21023 FirstScope 76
Tabletop Telescope - fig 7Look through the fi nderscope and roughly point your telescope at your target.
NOTE: Align the fi nderscope fi rst before proceeding. See the next page for directions. CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
8Center your target in the fi nderscope’s fi eld of view. Then make sure it is in the telescope eyepiece’s fi eld of view and tighten the altitude lock nut.CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
9 Focus your telescope by turning the two knobs under the eyepiece until you have a sharp image.CELESTRON 21023 FirstScope 76 Tabletop
Telescope - fig 10CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
11Celestron’s free SkyPortal app for iOS and Android can  help you locate and identify a wide array of celestial objects quickly and easily.

ALIGNING THE FINDERSCOPE

The finder is one of the most important parts of your telescope. It helps you locate objects and center them in the eyepiece. The first time you assemble your telescope, you need to align the finder to the telescope’s main optics. It’s best to do this during the day.*

  • SOLAR WARNING! Never attempt to view the Sun through any telescope without a proper solar filter!
    CHOOSE A TARGET
    Take the telescope outside during the day and find an easily recognizable object, like a streetlight, license plate or sign. The object should be as far away as possible, but at east a quarter mile away.CELESTRON 21023 FirstScope
76 Tabletop Telescope - fig 12 CENTER THE TARGET IN THE EYEPIECE
    Look through the telescope using your lower powered eyepiece. Move the telescope until the object you chose lies in the center of the view. If the image is blurry, gently turn the focus knobs until it comes into sharp focus. CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
13 LOOK THROUGH FINDERSCOPE
    Once the object is centered in your 20mm eyepiece, look through the finderscope and locate the crosshair reticle.CELESTRON 21023 FirstScope 76
Tabletop Telescope - fig 14 ADJUST THE FINDERSCOPE
    Without moving the telescope, use the three finger knobs on the finderscope bracket to move the finder around in the bracket until the crosshair appears over the same object you are observing in the telescope’s 20mm eyepiece.
    TIP: Try adjusting one screw at a time. Loosen one screw by half a turn and tighten another by the same amount to ensure the finderscope remains securely held in place.CELESTRON 21023 FirstScope 76 Tabletop Telescope -
fig 15 YOUR FINDERSCOPE IS NOW ALIGNED!
    It should not require realignment unless it is bumped or dropped.CELESTRON
21023 FirstScope 76 Tabletop Telescope - fig 16

YOUR FIRST NIGHT OUT THE MOON

The best and easiest target for you to try to view first is the Moon. Try observing the Moon at different points in its phase cycle. The best time to view the Moon is from two days after a New Moon up to a few days before a Full Moon. During this period, you will be able to see the most detail in the craters and lunar mountain ranges.

With the Moon visible in the sky, set up your telescope with the 20mm eyepiece installed. Move the telescope so that it is roughly pointing toward the Moon.CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
17Look through the finderscope and locate the crosshair reticle. Continue moving the telescope until the crosshair appears over the Moon.CELESTRON 21023 FirstScope 76 Tabletop Telescope - fig
18Look through the telescope’s 20mm eyepiece. Gently turn the focus knobs to adjust the sharpness of the image.
CONGRATULATIONS! YOU HAVE NOW OBSERVED YOUR FIRST CELESTIAL OBJECT!CELESTRON
21023 FirstScope 76 Tabletop Telescope - fig 19To get a closer view of the Moon, loosen the setscrews on the focuser and remove the 20mm eyepiece. Replace it with your 10mm eyepiece and tighten the setscrews to secure it in place. The 10mm eyepiece will give you significantly more magnification, making the Moon appear much larger.
NOTE: You may need to adjust the focus knobs when you change eyepieces to make sure you are getting the sharpest image possible.CELESTRON 21023
FirstScope 76 Tabletop Telescope - fig 20You can view many other celestial objects, such as planets, star clusters and nebulae using this same technique and your SkyPortal app to determine celestial objects’ positions.CELESTRON 21023 FirstScope 76
Tabletop Telescope - fig 21

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All rights reserved

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2835 Columbia Street
Torrance, CA 90503 U.S.A.
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SOLAR WARNING:
Never attempt to view the sun through any
telescope without a proper solar fi lter.
NEED ASSISTANCE?
Contact Celestron Technical Support
celestron.com/pages/technical-support
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References

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