Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Battery Replacement for Compustar Finderscope

Celestron Classic
  • Please log in to reply
2 replies to this topic

#1 WilliamAlexander

WilliamAlexander

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 30 Mar 2009
  • Loc: N Georgia

Posted 02 January 2025 - 03:32 PM

Hello, if this is covered elsewhere I cannot for the life of me find it, so here goes.

 

I'm trying to use the really old Polaris 8x50 Polaris right-angle finderscope that came with the Compustar 8 I bought way back before Halley’s Comet.  It requires a battery for the illuminated crosshairs.  I can’t determine what battery(s) it takes.  Obviously small round and cylindrical…. the battery compartment is in the shiny cylindrical bit.  

 

The online Compustar manual I found doesn’t mention the battery type.

 

Photo of the finder attached.  Anyone know?
 

Thanks!

 

IMG_3516.jpeg



#2 jurdea

jurdea

    Explorer 1

  • *****
  • Posts: 73
  • Joined: 13 Jan 2020
  • Loc: Centennial, CO

Posted 02 January 2025 - 04:07 PM

This finder used a 2.7 VDC H-2D mercury battery which is no longer available due to its mercury content.  There is an equivalent battery available through amazon, Exell Alkaline Battery A14PX, which is rated 3 VDC.  I ended up using 2 AG13 1.5 VDC batteries stacked together in a PVC sleeve with some spacer washers in between.  The original H-2D is a bigger diameter than the AG13's hence the need for the sleeve and is also longer than the stacked AG13's requiring the spacer washers to make the difference.  The Exell Alkaline Battery A14PX wasn't available at the time I came up with my workaround solution.



#3 33_Patitude

33_Patitude

    Lift Off

  • -----
  • Posts: 4
  • Joined: 05 Jan 2025
  • Loc: San Diego, California

Posted 05 January 2025 - 06:40 PM

Hi WilliamAlexander,

 

I have a very similar Celestron Polaris 8x50 Finderscope/reticle light on my C8. Mine came originally with a discontinued Toshiba 2MR9 2.7V Mercury Battery (pictured).

 

Like Jurdea pointed out, yes as far as I've found, the best replacement is an Exell A14PX Alkaline. I got mine off ebay for about nine dollars just a few days ago. But I wanted to add, to spare you some time, the replacement A14PX isn't an exact replacement in terms of dimensions. It's the right diameter, but not as tall. The light won't turn on when screwed all the way to 'on' (at least mine didn't). So my quick fix on that was to put a penny in the distal flat end of the chamber. It fits perfect, not permanent, and takes up the slack beautifully. You'll still be able to use the brightness onset fine adjustment screw on the back end, but not sure it's as effective with the penny in there.

 

There was a guy here who soldered-in wires to use an external battery. I want to look into doing that as well, to use two AAA rechargeables in an exterior battery pack.

 

Pat

Attached Thumbnails

  • Replacement A14PX Battery.jpg

Edited by 33_Patitude, 05 January 2025 - 07:02 PM.

  • mlord likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: Celestron, Classic



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics