Quote:
Originally Posted by Peter Ward
Having a guide sensor that is locked next to the imaging sensor cures so many guiding problems....eg differential flexure, focus sag, optical shifts with gravity and thermal changes etc. Plus being very close to the isoplanic area of the imager, AO signals from a near field internal guider have less error than systems set further away.
Why lessen your guiding options? Self guide, external guide, differential guide (STX) and adaptive optics. Sure guide scopes work, but are a rather limiting, and not inexpensive (guide scope with rigid focuser, mounting rings, mounting plate and a separate guider with its own power supply and cables) solution.
Funny, I recall last years "Astrophotographer of the year" using something that had self guide  (On ya Martin! )
A note to SBIG users, the manual states NOT to use ice with water cooling. An additional 6 degrees delta T is typical with room temperature systems.
Dessicants also work and are easily re-charged by the user.
Loss of gas = return to factory? 
Contrary to web misinformation, SBIG actually do set their CCD systems up orthogonally using a dedicated optical test bench.
At the end of the day, you pays your money and take your chances.
There are several excellent CCD manufacturers out there, I'm sure most users are happy with their choices for what ever reasons that are important to them.
Was that OK Fred? Not too much biffo?  |
Bah!...all moon landing hoax type "proof"
