Comparisons Celestron SkyProdigy 6 vs NexStar 6SE – Which is the better Schmidt? by Rizka Amir April 9, 2020 by Rizka Amir Coma is a term used in astronomy, and more so in astrophotography, to refer to the imperfections in the lens or another optical feature that results in chromatic aberrations visible… 0 FacebookTwitterPinterestEmail