Polar Scope Modification for Celestron CGEM DX Mount

This video will show you how to build and install a light inside your mount to illuminate your Celestron polar scope for about $20. Note...you do not want to over illuminate the polar scope. Use a higher rated resistor to lower the brightness of the LED!

[@MrHueJazz1]

Thank you so much. This is a great little modification. I'm surprised Celestron hasn't done something like this already.

[@rmyersh1]

Used a variation of your idea for an Advanced VX mount. Simple 3/4 inch PVC pipe
that inserts into open end of the polar scope. Illumination achieved via led lamp from
an Orion illuminated eyepiece. Threaded the lamp into the pipe. Thanks for the idea.

[@christophercraig9295]

My favorite part was when you said, "SHAZAAM!"

[@JohnS916]

Great job. Very practical idea. Could have used this the other night trying to hold a mini flashlite to the front of my CGEM while looking through the polar scope.

[@gothicm3rcy426]

the version I did, I printed a flat plate behind the pcb board and a small hole for the led.... I ran the led to the main switch so it came on when I switched the mount on :)

[@ubermick4208]

Resistor depends on how bright or dim you want your LED to be, and depends on the LED itself. If we assume a standard 5mm red LED, that has a voltage drop of 2v and draws about 20mA, you'd want about at least a 600 ohm resistor to avoid the LED going pop. BUT that will have the LED operating at full brightness, which would be way too much. I'd suggest a 2.2k 1/2w resistor.

[@tomjones2860]

This is brilliant great idea, well executed!

[@digitaltree515]

Absolutely awesome mod, dude!

[@goddess93101]

Excellent mod and video. Thanks! You should be working for Celestron :)

[@SATCOMSTA]

Like the idea.....

[@MrHueJazz1]

What ohm resister did you use?
Great idea!

[@astrageekette9692]

Well, gee. Things are different moving from a manual Dobsonian mount to a hand me down CGEM. I was wondering why I couldn't see the star patterns through the polar scope at night. Assumed that illumination happened when I flipped the switch. THANKS

[@Hollowsphere04]

Stanis, anyway you can construct and outline a DIY for a right angle polar scope? I find it absured that none of the major manufactures have developed an accessory for that. I know AP has one but it's only compatible with their mounts. I have the Advanced VX GEM from Celestron. Anyway, you can figure-out how to modify the polar scope into a right angle?

[@gunnarjensen5910]

Do you recommend the CGEM DX or the newer CGX ?? Does the CGEM DX suffice for imaging and tracking ??

[@MrHueJazz1]

Also, what size LED did you use, 3mm, 5mm, 10mm?
Thanks.

[@josephmaloney9565]

What is that watch battery for, please?

[@wizardz7938]

Why is it black in the middle

[@MikeHammer1]

Why bother with a switch. The current draw from an LED is trivial. Also, the LED mount prevents access to the motor mounts if adjustments are needed. A press fit would be better. And a potentiometer rather than a resistor would allow adjustment of the brightness.

[@philldavies7940]

Great idea. But you need to limit the current through the LED via a ballast resistor. Measure the voltage across the positive and negative terminals, check the LED datasheet for Vf (forward voltage , typically about 1.5 v) and If (forward current, typically a few milli-amps, depending upon brightness you want) then add a ballast resistor in series that achieves this . If you don't know how, its easy, 1 calculation, google LED ballast resistors. Otherwise you 'll have a supernova LED -burns bright but brief.