|
I’ll just offer my personal experience with my older SBIG ST7 camera (parallel model with TC211 guide chip) as an additional reference point. Apart from the small guide chip (newer models use the bigger chip), it is the only way I have been able to obtain 30 minute sub frames without star trailing at focal lengths of up to 1700mm.
My side-by-side efforts have proven to be inconsistent; sometimes I get nice round stars but often I don’t and I always seem to get progressive offsets between frames. I have really tried hard to fix these side-by-side issues but have never succeeded.
The self guiding capability of the ST7 often has me wondering did it download a new image, as the refresh did not reveal any movement between frames. I am using a top end mount, the Tak EM-200.
What I also like about the SBIG dual chip cameras is that the set up and tear down operations are much easier and simplified, just OTA, camera, power cable, parallel cable and auto guider cable. No second scope, side-by-side plate and additional guide camera.
So, based on my experience, my next CCD camera will be an SBIG but with a much larger guide chip and the faster download times of the USB version as my parallel downloads take approx 16 seconds. When I win the lotto that is! LOL!
Cheers
Dennis
|