Ritchey Chretien carbon truss
This telescope was designed to produce better images over a large photographic field. Coma makes it harder to measure star positions, and the Ritchey-Chrétien is coma-free, producing round stars over the entire field. The hyperbolic surfaces on both mirrors are not for the faint of heart. These curves are hard to produce and test. Unless you plan on doing photography and measuring star positions (astrometry) there is little reason for choosing the difficulty of this design.
The degree of field curvature is related to the difference in radii between the primary and secondary mirrors. A system with a flat field is possible, but requires a very fast primary with a deep, difficult to figure curve. The short focal length of the primary then dictates a large secondary causing more than 50% central obstruction. The differece between a ritchey chretien and another lens.
Modeling and Finite Element Analysis
All mechanics are machined at CNC using aluminum 6061
T6 and finally completely anodized black and red.
Toscanoptics company for many years working on optical RC very carefully. Our mirrors are totally figured by hand and tested in controlled laboratory conditions. All series of primary mirrors for RC are processed at least 1/18 PTV -1/60 RMS. So we get a value of the entire focal plane of at least 1/5-1/6 lambda - 1/40 RMS.
Each optic is supplied with test report.
Each secondary mirror is tested by interferometric test at 660nm
and finally in autocollimation with a flat reference.
Ritchey-Chretien truss Technical data
Primary mirror dia. 318mm 410mm 510mm 610mm
Optical dia. 315mm 408mm 508mm 608mm
Primary mirror aperture F/3 F/3 F/3 F/3
Equivalent focal F/9 F/9 F/9 F/9
Secondary mirror dia. 120mm 141mm 185mm 211mm
Obstruction 0.39% 0.36% 0.39% 0.37%
Back focus 350mm 350mm 350mm 350mm
Weight 26Kg 43Kg 73Kg 120kg
Price € 8100,00 15.780,00 26.500,00 56.200,00