| |
| | Re: SCTs and chromatic error on double stars |
 | | Going back to the Maksutov, it is worth realising, that the original designs of the scope that is now so common, were largely quite high focal ratio instruments (f/20 to f/35), and usually had seperate secondaries, rather than the 'silvered spot' designs. |
 | | The 'silvered spot' design, places a serious constraint on the optics, that the rear curve of the corrector, has to match the curve required for the secondary, this is cheap to make, but does not give such good correction as is possible with seperate optics. |
 | | It should be, because -- like an SCT -- the Maksutov is using a single layer of glass to correct spherical aberration. |
| www.science-one.com /new-6283324-4254.html (3312 words) |
|