Has anyone ever made...

[Beulah]

A telrad style finder?

I'm rooting through a bunch of parts (LEDs, resistors, mirror etc.) at the moment and am wondering if I can rig together one.

As they seem to be very hard to get at the moment, I was wondering if anyone has had a go and successfully made one.

[paler31]

I once made a ccd camera out of an old webcam but never a finder. It looks a bity complicated to just cobble one together. There is a greet web site that showes you how to make losts of different stuff. I made an led cube from this site, you might find something there. Its called www.instructables.com

Good luck

[Beulah]

That LED cube looks great. Don't distract me!!

[Bizibilder]

I've just had a look at my Telrad and it seems simple enough. There is a light source (LED?) enclosed in a lightproof box, one wall of which is made from the reticule - I assume a red plastic? coated in a black layer, with the reticle engraved so the light can shine through it. There is no obvious "optical" part ie no obvious lenses or focussing system. Light from the reticle passes along the Telrad towards the "observers" end where it meets a 45° front surface mirror and is reflected out through the top of the Telrad body. There is a clear plastic window here which may be some sort of lens? The light continues upwards until it hits the 45° sloping glass plate, where it reflects back into the observers eye. Hope this helps.

I suspect that the "difficult bit" would be the reticle? Not impossible to make but getting it calibrated would be tricky - and possibly unnecessary, as long as you could "self calibrate" to a known "size of circle" when using it.

[pixelsaurus]

Not quite a Telerad, but a red dot finder http://www.astunit.com/tonkinsastro/atm/projects/red-dot.htm

There are a few of the Stellafane page, about halfway down under "Other Components" http://stellafane.org/misc/links.html

[Beulah]

Roger, that's very helpful, thanks!

Mike the red dot finder plans looks very handy. Just about have the kit for that one.

[Cath]

That LED cube looks great. Don't distract me!!

LOL

[Beulah]

Glad you understand Cath..

Hmm, Google is my friend today, someone made their own reticule...the electronics should be fairly straightforward but I am wondering if printing out something like this on acetate would save effort in delicate scalpel work?