Illuminated Polar Scope

[cosmological]

This is my version. I originally tried a red LED but found it was too faint unless I had it right on top of the lens; I prefer to have it tucked out of the way and have the whole area illuminated, this way the light won't be too bright, so I decided to try one of my spare red Christmas tree lights.

The next stage was to go to Maplins and get a battery holder and clip to attach to the battery holder. I then soldered the bulb to the end of the wire.

The most expensive item there are the rechargeable batteries, the battery holder was £1.29 and the clip on the left (without the bulb) was £1.34 both from Maplins.

Then it’s just a case of connecting the clip which has the effect of turning the light on. The light actually appears brighter than that but I reduced the output of the camera flash and reduced the shutter speed to get bulb's own light to show. Also this bulb is rated at 6V so there is no chance of it burning out with these batteries.

I found the easiest way to attach the battery holder to the mount was to just simply tape it on using insulating tape, I only need it on there while I’m using the polar finder to align the scope with the celestial pole, once that’s complete then I can take it off.

By placing the bulb to the side inside the mount the red light isn’t too bright, I can see both the markings on the polar finder and the stars quite easily.