I am looking for a small portable apo refractor. I am wondering whether I should get the sky 90 with its 10mm advantage in aperture or TMB 80 with its perfect color correction. How do they compare under the stars?
Sky 90 or TMB 80
Started by Yang, 04/18/2005 10:47PM
Posted 04/18/2005 10:47PM
Opening Post
Posted 04/19/2005 04:45AM
#1
Yang Shuai said:
I am looking for a small portable apo refractor. I am wondering whether I should get the sky 90 with its 10mm advantage in aperture or TMB 80 with its perfect color correction. How do they compare under the stars?
I've heard APM will be coming out with a 95mm with a TMB apo objective. You might check with Markus to see when it's due out and what it's likely to cost.
Posted 04/26/2005 06:50AM
#2
Hello:
I have not used the TMB 80, but I do have a Sky90. I have not noticed any false color in focus, even on very bright stars or planets (and really, how often do we look at Vega with wide field refractors?). Out of focus there is some false color, but not in focus as far I was able to see. The wide field performance is very good. With the 31mm Nagler, it has a 5 degree field of view, so I usually don't use the finderscope. With a nebula filter, I have seen all the Veil in one shot, and both the North America and Pelican Nebula at once also. For planetary observing, it is diffraction limited, with very high contrast (judging by looking at the edge of the moon), so there's nothing more I could ask from it in this department. Looking at it objectively, nither scope is a slouch, and odds are you'll be very happy with either one. I'm happy with the Sky90, but that's just me.
Cheers
Mike Connelley
I have not used the TMB 80, but I do have a Sky90. I have not noticed any false color in focus, even on very bright stars or planets (and really, how often do we look at Vega with wide field refractors?). Out of focus there is some false color, but not in focus as far I was able to see. The wide field performance is very good. With the 31mm Nagler, it has a 5 degree field of view, so I usually don't use the finderscope. With a nebula filter, I have seen all the Veil in one shot, and both the North America and Pelican Nebula at once also. For planetary observing, it is diffraction limited, with very high contrast (judging by looking at the edge of the moon), so there's nothing more I could ask from it in this department. Looking at it objectively, nither scope is a slouch, and odds are you'll be very happy with either one. I'm happy with the Sky90, but that's just me.
Cheers
Mike Connelley
Funding Member
