Jump to content


Potentiometer Mod To Atlas EQ-G Polar Illuminator

This topic has been archived. This means that you cannot reply to this topic.
1 reply to this topic

#1 Trebor777



  • *****
  • Posts: 1207
  • Joined: 04 Jan 2008

Posted 18 March 2009 - 02:20 PM


I want to put a potentiometer on my Atlas to be able to control the brightness of the polar illumitator. I know I'll need a micro potentiometer in order to have it fit between the front panel and the circuit board.

1) Does anyone have any directions for me to help with the modification. (directions w/ pictures would be great)

2) What kind of micro potentiometer would I need and where can I get one? I know radioshack has them, and they're cheap, but I would like to know what specific one I should get.

I know I could just use a black sharpie to dim it a little, but I'd rather put the potentiometer on there.

Thanx in advance.

#2 Arctic_Eddie



  • *****
  • Posts: 3635
  • Joined: 30 Dec 2007

Posted 19 March 2009 - 08:26 AM

The size of the pot would depend on the voltage and current rating of the illuminator. For example, a 12V lamp drawing 100mA(0.1A) would consume 1.2W. Since the pot wired as a rheostat would have to consume some of this power you may not find one in a micro version that is sufficient.

I would first try various 2W resistor values in series with the positive lead of the illuminator circuit until you find one that is suitable. Values from about 22 ohms up to around 330 ohms would work. After finding the right one then just slide a piece of heat shrink tubing over the resistor and make it permanent.

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.

Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics