UNIT FINDER

The finderscopes that come with most low-end telescopes are pretty poor. They suffer from extreme chromatic aberration, are difficult to focus properly, and usually display inverted images which tend to disorient the user. Fortuneately, there is a better alternative available, and it costs less than $15.

Many department stores sell red-dot finders for BB Guns. These devices have a red LED which shines onto a coated lens. By looking through the lens, you can see a red dot projected in the distance. When the finder is properly aligned, the BB Gun (or telescope, in our case) will be aimed wherever the red light is shining.

One of the principal manufacturers of these is Daisy Corp. Their Electronic Point Sight fits the bill nicely. With a few minor modifications, you can turn this into an easy-to-use finder.

Adjust LED Brightness

The first modification is the dimming of the LED. The LED is actually too bright to use at night, without ruining your night vision. There are several different ways to go about dimming the LED. One of the more popular ways is to install a potentiometer circuit to act as a dimmer switch.

I opted for a simpler method: dabbing the front of the LED with fingernail polish. You may need to experiment with the amount you use. You don't want so much on there that you can no longer see the LED, but you do want enough to significantly dim the brightness.

Remove Lens Coating

Next, many people like to remove the dark coating on the lens. The coating makes it harder (if not impossible) to see fainter stars. However, the reason for the coating is to reduce "ghosting" of the LED image. By removing this coating, you will possibly see a second "ghost image" of the LED. I opted not to remove the coating, but if you wish to do so, many sites on the internet suggest using Muratic Acid.

Mount Finder

The final step is to mount the finder on the telescope. Move the finder to different positions on the telescope until you find a spot that is comfortable from the widest range of viewing angles. There are about as many different ways to mount the finder as there are people using them. You can buy a dovetail base from many gun shops, or you can use double-sided tape. I found a couple of strips of aluminum, drilled a hole in each end, and twisted into an L shape with a pair of pliers. I then screwed the short end onto the telescope tube and the long end to the finder. The result is pictured below.

Daisy Electronic Point Sight, mounted on a small refractor