Quote:
Originally Posted by Sunfish
So simply, without confusing the mathematics and physics which makes my head spin, with the mechanics: the suggestion is that if I buy a much bigger aperture , I had better be prepared for a much larger sensor with larger pixels?
It would seem that small refractors up to 800 are well paired with apsc size 4.3micron pixel sensors at 1.1 arcsecond but a much larger aperture can benefit from a full frame with 6 micron pixels ?
Where is the useful limit of tolerance , 0.8 to 1.2 “ ?
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You are on the right track. If you don't match your pixel size with the scope's focal length you may waste your money. For example if Francisco decided to get the 12.5" Planewave and use his present sensor, which I presume is one with pixels of around 4 micron, he would end up with a setup that not only has a much smaller field of view, but it would require the same exposure times and the only gain, not very dramatic, would be in resolution.
The limit for sampling rate is set by atmospheric seeing and I don't think going to less than 0.8 is beneficial, it would just increase exposure time without gaining resolution.
So basically the size of your pixels set the upper limit of your focal length and from there it is just a matter of choosing the largest available aperture for that focal length.