[gregbradley]

Nice work and your results mirror my experiences.

Although I have generally found 1 arc sec or .66 arc sec generally to be the standard used as per sampling theory.
Sampling theory states you need a minimum of 2X to obtain a decent sample. So 3X is often used then following that
theory. In 3 arc sec seeing, which is probably very common (on a good night perhaps) that gives you 1 arc sec/pixel as a guide
or if you have occassional 2 arc sec seeing then .66.

I have noticed though with my refractors versus my CDK that small pixels do make an image pop a bit more on the refractors but
seeing effects blur the images much more noticeably on the CDK to the point where I would not use the KAF8300 camera on my CDK17 with nearly 3 metres focal length. I have put 16803 camera (9 microns) and 8300 camera (5.4 microns) at imaging the same object (M104) and the 16803 captured far more detail with less noise and blur in the same conditions than the 8300. This was proven over several images.

The trouble with the 8300 chip is small field of view. Also small well depth. QE is the same. So that limits it as well. Its harder to get a pleasing image with a smaller field of view on the same scope.

Also smaller FOV CCDs will show up the tracking errors more easily as it creates a digital zoom so to speak due to the smaller field of view.

In real life though other factors are more dominant though than pixel size which is really only an issue with long focal length scopes.
QE, Noise, accessories, download times, weight, reliability, build quality, cost, field of view, autoguiding ability, focusers, etc etc
tend to become dominant. Of course cost is the main consideration usually as the large 11002/16803 chips are a lot more expensive than KAF8300 chips. Plus accessories and scope that can take them are vastly more expensive.

Another point with the larger chips is the increased sensitivity to tilt, squareness, flex and the level of correction of the optics (round stars to the corners without vignetting, only the largest and the best focusers/flatteners cope). They show these factors up more easily.

Another factor is cost of the larger filters.


Greg.