Connecting 350D

I have to ask a really basic question that I just cannot seem to gleam from a search here and on the web. It is simply:

When a DSLR is connect to a telescope via a T-adaptor, what lens is used? Interested in some planet/moon/cluster shots.

From what I understand, the normal detachable lens are removed from the camera and not used. The T-adaptor connects directly to the camera body.

Then, the T-adpator is connected to the telescope - but is this with or without the normal telescope lens? If not, how does the telescope magnify for the camera? If so, does the T-adaptor attach to the lens directly? I have 1.25" sized lenses - so are these used? It is hard to get a full field of view with a 9mm or 6mm lens by eye, what hope is there with a T-adaptor?

Finally I have a set of extension tubes. The provide a EOS mount and a 58mm front thread. Could the base be used with anything to attach to the telescope.

Is this any good?

cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem...K:MEWA:IT&ih=012

Hi Brendan, I just saw your PM. I take it you want to shoot through the telescope right? If so here is the set-up:

You need this : Camera - T ring - T adapter. I have a T ring here, I'll contact you via PM. Also you need a T adapter, you can buy one from celestron (model no. 93625) or use the barrel of a barlow lens which screws into the T ring.

As for the ebay link, I see that an eyepice lens is used. I can't offer much advice on that as I've never used such a set up, maybe anybody else can comment?

When a DSLR is connect to a telescope via a T-adaptor, what lens is used? Interested in some planet/moon/cluster shots.

From what I understand, the normal detachable lens are removed from the camera and not used. The T-adaptor connects directly to the camera body

Correct, no normal camera lens is used, but as above you need the camera- t ring- t adapter.

Here's the t adapter as an example:
www.amazon.com/Celestron-93625-Universal...dapter/dp/B0000665V6

Keith..

Thanks - but I'm still baffled by what does the magnification?

The telescope does the magnification.

What you are doing is replacing the camera lens with the telescope lens or mirror. Your ordinary zoom lens may have a focal length range of 18-55mm. The magnification relative to normal vision is the ratio of this focal length to the diagonal of your image sensor, which with DSLRs is about 28mm (APS-C type cameras) so your normal zoom give magnification of about 0.7 - 2X depending on zoom setting.

Your telescope may have a focal length of say 1000mm - this is the lens/mirror diameter x f ratio, so a 200mm reflector f5 would have a focal length of 1000mm. The magnification would be 1000/28 = 36x.

As an aside, when you use webcams to image planets, the magnification is much greater and this is because the webcam chip is smaller, having a diagonal more like 5mm, so the same scope would give 200x magnification on a webcam.

HTH.

I also have a 350d and what was recommended to me at the time on these boards was the T-adapter and Revelation Eyepiece Projection and Prime Focus Camera Adaptor at this web address: www.telescopehouse.co.uk/page.aspx?theLa...Lk8XHVr1&action=

You can use it with either an eyepiece in the barrel (eyepiece just drops down inside it) or on its own using only the telescope mirror for focusing. There is also the facility to shorten the adapter if necessary. I've had no problem using this setup.

If we could just get the weather down the south of the country.

Hope this helps

Thanks guys. Joanna, that looks what I thinking off. Paul - what you are saying is that the camera with the telescope becomes like a prime lens?