charity shop find telephoto lens.

[Lux1]

Had a quick look in a charity shop today and came out with a Pentax telephoto lens, a Canon AF35M, a Kodak lens hood and a UV filter.

All for £5.

Two questions, are any of these any good and is the canon considered a srl camera?

Now then onto the DIY part, the telephoto lens was dirt cheap and has good optics, it won't fit the camera so I was thinking of attaching a low power eyepiece and making a wide-field scope. Is this a possibility?

[Doc]

The camera is basically a point and shoot camera, the len's doesn't come off does it?

You can't fit an eyepiece to the rear end of the lens, it doesn't work like that. I would imagine the Pentax has either PK fittings or M42 fittings, so you will need an adapter with one of the above on one end and the threads of your SLR camera on the other. So maybe a M42-EOS adapter if you are using a Canon.

[FraserClarke]

You can't fit an eyepiece to the rear end of the lens, it doesn't work like that.

themos had a nice example of how to do this;

http://stargazerslounge.com/diy-astronomer/99189-turn-your-camera-lens-into-grab-go.html#post1393368

I build something similar for my 300mm f/4 lens, and it works quite well; though the back focal distance isn't enough to get a diagonal in, which makes viewing a bit awkward.

I'm not sure that lens will be great though -- looks like one of those not brilliant push-pull zooms. However, as you have it, and if you have a suitable eyepiece, it wouldn't be a big waste to try it out as a telescope. Probably M42 thread on the back as Doc says.

[Odd Thomas]

Had a quick look in a charity shop today and came out with a Pentax telephoto lens, a Canon AF35M, a Kodak lens hood and a UV filter.

All for £5.

I love charity shops.

[Lux1]

.

I'm not sure that lens will be great though -- looks like one of those not brilliant push-pull zooms.

It twists in 3 parts, one to focus, one to zoom and one to reduce the diaphram size.

Coupled with a 25mm eyepiece it gives excellent daytime views at 8x. I reckon I could get 40x out of it.

[Psychobilly]

I have made EP adaptors for some of my camera lenses as well...

One quick and dirty way of doing it is to use a rear lens cap and 35mm film canister...

Billy...

[Doc]

themos had a nice example of how to do this;

http://stargazerslounge.com/diy-astronomer/99189-turn-your-camera-lens-into-grab-go.html#post1393368

I build something similar for my 300mm f/4 lens, and it works quite well; though the back focal distance isn't enough to get a diagonal in, which makes viewing a bit awkward.

I'm not sure that lens will be great though -- looks like one of those not brilliant push-pull zooms. However, as you have it, and if you have a suitable eyepiece, it wouldn't be a big waste to try it out as a telescope. Probably M42 thread on the back as Doc says.

Wow didn't know you could do this. Sorry folks.

[BinocularSky]

though the back focal distance isn't enough to get a diagonal in.

Depends how you do it. I made a guidescope for my old C5 by taking off the nosepiece and cementing the diagonal to the lens (Ross 300mm + x2 tele-extender) arrangement. I nicked the idea from Klaus-Peter Schroeder, who showed me a similar arrangement with a Russian 1000m f10 mirror-lens that he uses when he chases eclipses to parts of the world where he won't risk his Questar.

[FraserClarke]

Depends how you do it. I made a guidescope for my old C5 by taking off the nosepiece and cementing the diagonal to the lens (Ross 300mm + x2 tele-extender) arrangement.

Now that's a clever idea

[Lux1]

The telephoto lens provides excellent low power, wide field views at around 7x.

The lunar landscape is impressive at 40x, but detail above this is hit and miss.

Saturn's rings are just about resolvable.

I will probably make it into a finderscope. Should work well.

Does anyone have an old star-diagonal they don't use? .965 or 1.25 is fine, I could modify, - I have just thrown one away a few weeks back!