24 inch (61cm) F8 Ritchey-Chrétien met carbon Truss buis van RC Optical Systems. Amateurs go PRO!
Niet voor niets kiezen topfotografen als Russel Croman, Tony Hallas en Robert Gendler voor RCOS Ritchey-Chrétien telescopen.
A Ritchey-Chrétien is a specialized Cassegrain reflector utilizing true hyperbolic surfaces. All reflectors typically have an aberration called coma - all except for the Ritchey-Chrétien. The hyperbolic mirrors of the Ritchey-Chrétien make this design coma free, which results in a much smaller spot size. This is the #1 reason why nearly all professional observatories have chosen the Ritchey-Chrétien design.
Since Ritchey-Chrétien optics are two mirror optical systems, they have no Spectral Dispersion or Chromatic Aberration. Chromatic Aberrations are common in Catadioptric Systems and caused by their refractive element known as a "corrector plate". See diagrams of Chromatic Aberration on and off axis in a Catadioptric system.
In addition to being coma free and chromatic free, a true Ritchey-Chrétien offers:
- Only two surfaces for less light loss - Catadioptric type optics have 4 surfaces (two are glass!) . Some APO's have 6 surfaces. Each surface degrades the amount of light getting to the focal point.
- No refractive elements - Glass scatters light, especially in IR where CCD cameras are most sensitive. A Ritchey-Chrétien has no refractive elements, such as a corrector plate.
- Flatter Field - The lower the amplification factor of the secondary mirror, the flatter the field. For example, the RC has a 2.7x secondary, whereas, a Schmidt-Cassegrain has a 5x secondary. The RC has a much flatter field!
- Smaller Spot Size on and off axis. Examine this spot diagram to see the difference!
For these reasons, the Ritchey-Chrétien is ideal for medium to large format CCD or film photography, where a large aberration-free field of view is required. It is also a superb visual instrument.
RC Optical Systems 24 inch (61cm) F8 Ritchey-Chrétien Carbon Truss:
- System: 24" F/8;
- Order Status: Open;
- Back Focus: 16";
- Carbon Tube Length/Diameter: 70"/29";
- Primary Focal Length: 72";
- Primary Hole: 4.5";
- Primary to Secondary Spacing: 48.20";
- Radius of Field Curvature: 25.30";
- Secondary Amplification: 2.70X;
- Secondary Size: 9";
- Base Weight: 240 pounds;
- 24 inch F/8 Ritchey-Chrétien - Astro-Sitall (zero expansion) Glass Ceramic Optics certified to 1/4 wave P-V and 1/20 wave RMS or better;
- Fringe analysis and interferometric data supplied with each optical set;
- Enhanced Aluminum (SiO2/TiO2) overcoat - 96.9% reflectivity;
- Low Expansion, light weight carbon fiber truss tubes for superior performance and stability;
- Honeycomb CNC Machined 6061 Aluminum Back Plate;
- 6061 and 7075 Aluminum components - All CNC Machined;
- Precision Secondary Mirror Focuser;
- 2-Stage Primary mirror baffle with internal knife-edge light stops;
- Conical Secondary light baffle;
- RCOS "Focus and Forget" Technology;
- CNC Machined "light weight" auxiliary mounting plates - top and bottom;
- CNC Machined "light weight" mounting plates - on each side;
- Losmandy RDF-90 Finder Scope 3-point mounting bracket;
- RCOS large format, 5 piece "Fixed Instruments" Rear Cell Adapter Set (FIA);
- CNC Machined Dust Cover for Primary Mirror;
- Shipped fully assembled, collimated, and ready to use.