# Low cost Ritchey-Chrétien?

1. May 7, 2008

### chemisttree

AstroTech has an f/9 6" for around $1,300 and an f/9, 8" for$3,000. Anyone heard anything bad about these? I've been pretty impressed with AT's products so far... my AT80ED APO is pretty nice for the price and would make a good guider for something like this. I've heard that collimation can be a problem with RC scopes. Any experience with them?

2. May 7, 2008

3. May 7, 2008

### turbo

I don't know of anybody yet who has posted reviews on this scope. It appears to lack the back-focus for any sort of visual observing (unless perhaps you can view without a diagonal). That aside, if you're serious about DSLR astrophotography you might be pleased with this OTA.

Lots of folks getting into astrophotography these days are using small APOs with fast focal ratios, and some are getting extremely impressive results. Look what Greg Parker can do with a Sky 90.

http://www.newforestobservatory.com/

4. May 7, 2008

### chemisttree

I posted this before I looked on Cloudy Nights for info. The scopes appear to be brand new and no one has one yet. The one review (if you can call it that) used the prototype.... and there are pics as well.

See this thread. Backfocus appears to long enough for visual, if you can believe the pic.

That Tak as well as others were on my list. Thanks for the website, definitely food for thought.

5. May 7, 2008

### turbo

You're welcome! Greg (imager) and Noel Carboni (image processor) are members of an astronomy forum that I'm on, and they have an incredible astrophotography image book in the works. They have produced so many APODs that I have lost count!

Greg is pulling off stuff with the Sky 90 that I could never have accomplished with my 6" Astro-Physics APO during the film days. I've got a couple of Canon 30Ds, and after I've reconciled some financial doldrums (unemployed due to medical disability) I hope to house that instrument in a roll-off-roof observatory and jump into digital astrophotography.