"Herschelian" Quotes from Famous Books
 ... perpendicularly, and send the rays through [Page 45] an opening in the mirror at M. This form is called the Gregorian telescope. Or the mirror M may be slightly inclined to the coming rays, so as to bring the point F entirely outside the tube, in which case it is called the Herschelian telescope. In either case the image may be magnified, as ...
— Recreations in Astronomy - With Directions for Practical Experiments and Telescopic Work • Henry Warren |
