Quote:
Originally Posted by toyos
With my 12" LX200 I couldn't get the stars as round as I did with my refractors, even with minimum exposure times. I used Canon 40D with them. I guess that's the way SCT's are.
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How round your stars are probably isn't to do with the fact it's a SCT directly. SCT's often have poor flat fields, so you might get illongation of stars on the edge of FOV, but other than that you should have circular stars if your tracking and focus are good.
It's more likely that you don't have circular stars because SCT's typically have much longer focal lengths than refractors, so any tracking error in your mounts will be much much more obvious on the SCT than refractor.
Roger.