I am looking at getting a new planetary camera to go with my Explore Scientific 127ED f/7.5 refractor. I am investigating either an ASI662MC (2.9um chip, FPS=102) or ASI678MC (2.0um chip, FPS=47.5) camera. I have seen a lot of discussions about "sampling" to get the best image possible from your scope and camera combination. When I use the Astronomy Tools site to get a feel for what these two cameras would give with my ES127, it was not encouraging.
With the ASI662MC, the only way I could get good sampling was to use my 0.65 focal reducer with the scope. Anything above that would give me "slight" oversampling.
With the ASI678MC, the only way I could get borderline good sampling was again to use my 0.65 focal reducer. Anything above that would give me "slight" or "major" oversampling.
I use the ASIAIR as my primary imaging system. In Video Mode it has several "zoom" options (1080P, 720P", 480P, 360P, and 240P). This is similar to Region of Interest (ROI) with most cameras, though not as flexible. According to ZWO, these options will display the length and width of the center part of the chip corresponding to the chosen video mode value. Using one of the lower values, I can still get a decent size disc of at least Jupiter and Saturn even with the focal reducer. The ASI678 would give me the largest disc. ASI662 FOV would be about 5.5' x 3.7' while the ASI678 FOV would be 3.7' x 2.8'.
I also have a ASI533MC (3.76um chip, 20FPS) for general deep sky imaging. It has a rather slow FPS but has good sampling at 1x and minor oversampling at 1.5x and 2x. With Barlows it has a smaller FOV than the other two so I could get a larger disc size.
So I am at a quandary. How important is sampling? When using ASIAIR Video zooms, is there any loss of detail?
JohnD
