Shrinking a Telrad (long brainstorm)

It would seem that the Telrad could be made about 2-3/4" shorter if the battery pack were replaced with something smaller. Then the entire unit could be shortened to eliminate the now-empty space.

The battery pack could be replaced with a small linear regulator for use with external power (which you might have anyway for a dew heater), or a coin cell, which might only last 1/5 as long, but still should be good for days of use.

This might take some delicate surgery, especially if you want to maintain the quick-release feet (at a reduced spacing), but it seems possible.

I envision cutting the body just in front of the attachment of the reticle assembly, and just behind the front feet and then joining the parts. I may leave a little extra length for the pulser.

Why would I attempt such a thing? Well, I really like the Telrad: it's reticle is relatively large, well calibrated, and has little parallax. It's also reasonably priced for its quality. Furthermore, several useful accessories are for it: solar finders, right-angle mirrors, and pulsing.

I could also envision removing most of the base until it is barely thick enough to the Telrad feet.

The Telrad won't ever be svelte, but perhaps these changes would make it less awkward.

Good idea? Bad idea? Let me know. Also, do you know an appropriate adhesive for reattaching the parts?

Allen

Your Idea seems sound to me, and my #1 favorite adhesive is EPOXY, it will glue stink on a rose, and every thing else for that matter.

Hi Allen:

The problem I have with mounting a Telrad is finding a spot that is wide enough between the focuser and the magnifying finder....

But as far as shortening the Telrad itself, this is not a bad imitation and it too runs on 2 AA batteries, one of the great features of the Telrad. Those batteries are cheap and last forever. With those little coin cells, if I leave the finder on for a couple of days, the battery is dead and cost a few bucks and is not so easy to find.

http://www.apogeeinc.com/product.asp?itemid=72&catid=46

Jon

After some careful thought (and thanks to all of your comments) I've got a plan:

1. Mount the pulser across from the dimmer control. There's just barely enough room and, even after trimming the circuit board, it still slightly (almost trivially) obstructs the lens. The details are gory, but it gets the bulky pulser out of the soon-to-be eliminated battery compartment. Almost done.

2. Replace the battery with a pair of coin cells in holders, one on each side of the optical path.

3. Shorten the Telrad and base to match.

4. Replace the pulser and dimmer controls with a custom microcontroller-based implementation. This should save power by eliminating resistive losses and give better control (eliminating the pulser's inherent 50% dimming).

Each of these steps is rather independent, so I can stop at any time. Step 4 is probably the most difficult, and the most fun.