After the grinding of the 33cm mirror of the dobsonian I needed a somewhat tougher project in my ATM life. I deceided to make a 12inch ritchey chretien cassegrain telescope. This project will be very tough because both mirrors are hyperbolical (conical constant smaller than -1). With the aid of the book "telescope optics" and a lot of calculation and tweaking I came up with an optical design that suited my needs.

I already started grinding the optics. The primary is only slightly hyperbolical and will be foucault tested. The secondary will be the toughest part of the optics and will be figured using interferometric newton rings using a negative concave mirror.

However, what most people do not know is that an RC has a curved field so stars in the edges of the FOV will be eleongated and somewhat out of focus. For this an correcor is needed. With smaller CCD chips this will be not needed because the errors are barrely greater than the airy disk.