Ritchey-Chretien Astrography

Ritchey-Chretien telescope is a powerful in astrograph for flat, sharp and large of imaging field.  Generally, Ritchey-Chretien telescope can cover more than 8cm of imaging field and be the popular telescope in most professional observatories.

All mirrors (primary & secondary) were made from quartz glasses and covered with 99% reflection power dielectric coating. Because of the very low thermal expansion in quartz glass, the mirrors could reach to the accuracy of hyperboloid surface much better than 1/12 wavelength.