Re: Celestron Omni XLT 150mm Reflector vs Refractor
Posted: Fri Aug 23, 2013 10:13 am
Excellent analysis, Weixing!
I have the Celestron C6 f/10 SCT OTA. It has good sharp optics and I consider it to be just about the largest airline portable scope in terms of aperture. I brought it to a dark sky site in Western Australia last April, hand carrying it into the cabin, with a Vixen Porta mount and a Manfrotto tripod going into the checked-in luggage.
IMHO, for refractors, I think a 5-inch class (120-130mm) ED or APO is the most optimum (the sweet spot), provided the model is light weight, in terms of resolving power, objects viewable and demands on a mount / portability. Having much better colour correction than a 6" (150mm) f/5 achro, I would rate it as 'Good' or 'Very Good' for planets, 'Good' for portability, and then adopt your other ratings above on the other attributes on the 6" achro. I would therefore rate it, overall, above a 6" achro, a 6" reflector, and a 6" SCT; the 6" scopes would likely edge it out marginally on DSOs and planets (SCT and reflector only).
In summary, and to repeat, I would recommend consideration of the Skywatcher 120mm ED, as it is among the cheaper and lighter (5 kg) 120mm EDs out there. I have the older champagne colour model; the current model is black.
My above comments apply to visual use only, as astrophotography has a very different set of considerations.
I have the Celestron C6 f/10 SCT OTA. It has good sharp optics and I consider it to be just about the largest airline portable scope in terms of aperture. I brought it to a dark sky site in Western Australia last April, hand carrying it into the cabin, with a Vixen Porta mount and a Manfrotto tripod going into the checked-in luggage.
IMHO, for refractors, I think a 5-inch class (120-130mm) ED or APO is the most optimum (the sweet spot), provided the model is light weight, in terms of resolving power, objects viewable and demands on a mount / portability. Having much better colour correction than a 6" (150mm) f/5 achro, I would rate it as 'Good' or 'Very Good' for planets, 'Good' for portability, and then adopt your other ratings above on the other attributes on the 6" achro. I would therefore rate it, overall, above a 6" achro, a 6" reflector, and a 6" SCT; the 6" scopes would likely edge it out marginally on DSOs and planets (SCT and reflector only).
In summary, and to repeat, I would recommend consideration of the Skywatcher 120mm ED, as it is among the cheaper and lighter (5 kg) 120mm EDs out there. I have the older champagne colour model; the current model is black.
My above comments apply to visual use only, as astrophotography has a very different set of considerations.