I plan on saving for $3-5k for a kit for astrophotography

[Athiril]

What are my options? Not right now but for the future.

I'll be using a Canon EOS system, probably will have upgraded from my EOS 30D (f/11.8 diffraction limit) to a 5D (f/16) or 5D Mk II (f/11.8).

But it would be nice to use a 6x7cm system, if any telescope in this budget range provides an imaging circle big enough for 6x7 format film?

I dont want to use a CCD accessory specifically for imaging eiher.

[jase]

Daniel,
For the budget you're talking, its going to be a hard push to get a telescope that will fully illuminate a 6x7 medium format camera. You might be able to pick up a second hand Takahashi FSQ or another scope with a sizeable field flattener, but you'd blow the budget in one go and have nothing to mount it on. Would suggest you search these forums to get an idea of a starting imaging rig and work upward from there. Clearly, your choices largely depend on what you want to achieve in astrophotography.

[Colsmith]

Depends if you want to do solar system/DSO/widefield?

For most DSO work the following should get you off to a good start:

EQ6 Pro Mount $2,100 (Bintel)
Orion ST80 Guide Scope $339 (Bintel)
Orion Starshoot Autoguider $469 (Bintel)
Canon EOS T-Ring $39 (Bintel)
2" Extension Tube $39 (Bintel)
IDAS-LPS-V2 (Optional) $300 (Approx)
WO 0.8x Flattenr/Reducer (optional) $300 (Approx)

for a total of $3,586, that leaves about $1500 for a telescope:

Orion EON 80 or SW Black Diamond 80 are both good 'scopes.

Of course all this takes you to the upper limit (perhaps leave the filter and flattener till you know what you're doing). You will also need a laptop for the autoguider, some sort of power supply and various cables and other bits and pieces.

Hope this helps ...

[Kal]

For a refractor, to cover a full frame 35mm without vignetting you will need a scope with a 2.7" (or greater) focuser & field flatterner. The smaller refractors with 2" focusers & flatteners will only cover an APS size chip generally. To cover medium format 6x7 you will be best off with a 3.5" or greater focuser (& flattener).

Petzvel refractors, like the Takahashi FSQ or Televue NP, have the field flattener built into them.

I think the cheapest refractor that will meet your requirements is the takahashi FSQ-85ED (http://www.optcorp.com/product.aspx?pid=1-600-605-873-11546) which will give you a 60mm imaging circle, large enough for medium format photography, but at US$2995 it will blow your budget.

[Colsmith]

Kal, quite right. I should have mentioned the rig I detailed will NOT cover 6x7, will likely cause some vignetting at 35mm (EOS 5D) but will cover an APS sized DSLR OK.

If you need 35mm or 6x7 coverage start with a good mount ($2100) and maybe a william optics flt98 with a 3.5" focuser ($3300 from myastroshop) and get the autoguider later? (Still blows your budget tho :shrug:)