12x50 bins into finderscope?

[chemtom24]

was just wondering whether I could use one leg of my 12x50 binos as a finderscope, which would then have neximage atatched to it for guiding.

I cant see any real problems with this as other people use 8x50, 9x50 etc as cheap alternatives. I think Il need to make some kind of device to atatch the neximage tho, and focus it.

So in theory (andall being well, in practice) this idea should work??

[keithatrochdale]

Peter Drew may well be able to help you with this, he made a spotter scope the other day that was very impressive out of half a pair of binos (using the original focuser) and a tube. I have sent him an e-mail pointing at this thread.

[chemtom24]

thanks Keith

[glowjet]

I do not know whether anyone has tried an old telephoto lens, the old M42 screw types, excellent optics and you can buy a 11/4" focusing adapter from Baader which screws on the end to take the guide cam.

[Psychobilly]

I use old M42 (or T-threaded) lenses as guidescopes...

Anything wrong with the bins? If not rather than destroy them take a look on Astroboot and get some bit's an pieces of there...

[michael.h.f.wilkinson]

My first finder was a 10x50, made from damaged bins. Worked a treat. Have not tried guiding with them, but it should be possible. 12x50 may show a restricted FOV, but then my current finder is 16x70 with 4.4 deg FOV, which is sufficient.

[chemtom24]

nothing wrong with the bins but i never ever use them and have had them for years. they are widefield 6 degree fov.

can anyone see me having problems using the neximage camera? its the same as the spc900, and its unmodded.

[Peter Drew]

You would need to use just the objective in its tapered barrell to which you would have to add a tube and a means of focusing. An easy job if you have access to a lathe but a bit challenging if you have to go the "Blue Peter" route.

[chemtom24]

thanks peter. is there any formula for working out how far out the focus point is? i was thinking about having two tubes one slightly smaller than the other which slide in/out to form a focuser

[Polar Bear]

Have a look at one of my efforts it may give you some pointers.

http://stargazerslounge.com/diy-astronomer/121187-been-raiding-cupboards-again-20x50-finder.html

Paul

[chemtom24]

cheers paul. if i understood peter correctly, i should just replace your eyepiece with my neximage and so long as its focussed, it will worfk as a guidescope.

[Polar Bear]

cheers paul. if i understood peter correctly, i should just replace your eyepiece with my neximage and so long as its focussed, it will worfk as a guidescope.

Providing you get everything lined up I can see no problem with that.

Plumbers merchants and even B&Q can be a good source for plastic tube bits.

[michael.h.f.wilkinson]

Do note that though the focal ratio is fine for a guide scope, the focal length is a bit short, so it may be less accurate than say an ST80.

[chemtom24]

wooohoooo i got somethign assembled and focused ok just need to wait for my heq5 to turn up today sop i can star test to see if neximage will pick anything up, if not, I've just had ap honecall telling me I've been approved for a credit card! ahh once more life is good again

will post a pic later on

[chemtom24]

Providing you get everything lined up I can see no problem with that.

Plumbers merchants and even B&Q can be a good source for plastic tube bits.

recently knocked through an outhouse toilet wall to make a utility room for my mother, used some old plastic pipe from the cistern!