LewisM
01-09-2016, 05:38 PM
Anyone here tried a Baader Aspheric in a fast refractor without a flattener to see how much it tames field curvature?
I use a Tak Sky 90, and at f/5 and change, it does have distorted stars visually at the field edge to about 20% in using a TV 20mm Plossl. The curvature is almost mitigated with narrower FOV EP's, but I love the wide "Porthole in space".
So, was considering one of the Baader aspherics to see if it will tame it some, instead of buying a flattener (I have the Tak reducer flattener, but it's an imaging one, being too short focal length for visual)
I use a Tak Sky 90, and at f/5 and change, it does have distorted stars visually at the field edge to about 20% in using a TV 20mm Plossl. The curvature is almost mitigated with narrower FOV EP's, but I love the wide "Porthole in space".
So, was considering one of the Baader aspherics to see if it will tame it some, instead of buying a flattener (I have the Tak reducer flattener, but it's an imaging one, being too short focal length for visual)