[74tuc]

Hello Gav,

Your cameras sound wonderful - the EOS DSLR's are very nice indeed.

Using cameras like the EOS 1D sets the bar very high.

In astrophotography the most important thing is the mount / pier and footing. You cannot afford to compromise on these, so expect to spend more on the mount combination than the 'scope. As a start you will need to select the hardware and determine the weight of what you are going to put on the mount. Eg. You may have a telescope and camera and an auxillary guide 'scope for off axis guiding plus sub-mount for the guide 'scope. As a rule of thumb I would select a mount that can carry 150% of that weight.

For large sensors (EOS 1) you need a 'telescope that provides a large flat and well corrected field (at least 40mm diameter un-vignetted image circle).

The telescopes that provide these will be refractors like the Tak. FSQ104 that has a 4" focuser or a fast RC camera like the Tak. BBRC 250.

For smaller image sensors you cannot go past the F2.8 Tak. Epsilon series astrographs.

Having said that you would have to look at the suitability of using a normal DSLR for deep sky photography as they have filters that cut-out most of the red emissions from nebulae and are generally more noisy than cooled CCD's. But for medium length exposures (say 5 mins.) you could get some stunning widefield pics.

Well thats my two bobs worth Gav,

Clear skies and good luck,

Jerry.