DetailsThe 12" F/8 Ritchey-Chretien Truss Tube OTA from TPO is an all round excellent scope that boasts incredible versatility, maximizing every inch of it's aperture. The fixed position quartz primary mirror utterly negates image shift, and also removes the otherwise frustrating task of collimating a scopes primary mirror. Furthermore the carbon fiber truss tube design drastically reduces the threat of possible temperature shifts causing flexure, the design lending itself to minimizing thermal shifts. The Ritchey-Chretien design has virtually no coma, chromatic aberration, or spherical aberration, and is an all around improvement to the Cassegrain while attaining many of the same objectives. The TPO 12" F/8 RC then, is a superlative astrograph capable of almost any imaging task. One of it's most notable features is indeed it's extreme versatility and adaptability. The only astro-imaging task that it is not exceptionally well suited to is wide field, as it does have a notably narrow field of view. This Third Planet Optics (TPO) Ritchey Chretien telescope has 12" of aperture and a focal length of 2432mm . The concave hyperbolic primary and convex hyperbolic secondary are made from low expansion quartz, and finished with a scratch-resistant highly reflective 99% dielectric coating for great contrast. The primary mirror is fixed in place in a metal mirror cell, and the secondary resides in a metal housing that can be collimated.
- Additional Information
SKU OS-12RC-TT Manufacturer TPO Telescope Series TPO Ritchey-Chretien Optical Design Ritchey-Chretien Mount Type None - Optical Tube Only Warranty 2 Year Warranty Telescope Aperture 12" Telescope Focal Length 2432mm Telescope Focal Ratio f/8 Optical Tube Weight 52.9 lb. Optical Coatings 99% Dielectric Tube Color or Finish Carbon Fiber Look Diagonal Included? No - Sold Separately Finder Included None OTA Mount Type Losmandy-Style Dovetail
- Included Items
- TPO 12" f/8 Ritchey-Chretien Truss Tube OTA
- 3" Crayford Focuser
- Two Losmandy D Style Dovetails
- Questions & Answers
Product QuestionsHi: Does your 12" truss tube come with a a cover to protect the primary? Can one use it for visual observing and how is it visually? Can you see any secondary reflections? Also, is a focal reducer to f5 or so available? Thanks so much, LarryQuestion by: Morstar on Aug 19, 2014 3:00:51 AMThe 12" Truss RC does not currently include a primary mirror cover.
You can use the scope visually, but the large secondary mirror that helps imaging illumination will lower visual contrast compared to similar aperture scopes. The optics are very sharp but must be accurately collimated for best performance.
The scope is baffled to prevent most off axis reflections, but a shroud may help with this.
People have had good luck with the Astro-Physics CCDT67 focal reducer, which can lower the focal length to around f/5.4-6.0 depending on spacing, but this only works for an imaging circle around 25-29mm. Lunt Engineering is working on an f/6 reducer for larger sensors, but it has not been released yet as of mid-August 2014.Answer by: Chris (Admin) on Aug 19, 2014 11:09:21 AMWhat is the % obstruction by the secondary mirror (diameter or area should be specified in answer)? Thanks.What provision do the TPO 12" and 14" f/8 Ritchey-Chretien Truss Tube OTA have for finder scope (I.e., I plan to utilize one of the Losmandy dovetails to mount the telescope and the other for guide scope)? I think I see a finder scope bracket in one of the photos, but no detail is provided on finder scope mount compatibility?Do you have the image circle in mm ? Also is there a focal reducer available for it and what is the image circle in mm with that focal reducer.
Thank youQuestion by: Benoit Gagnon on Aug 23, 2015 3:13:00 PMWithout flattener, the image circle is 30-35mm.
You can use the AP-CCDT67 focal reducer which will give you approximately a 26mm. Also, Teleskop Service does make a corrector that will increase the image circle to 45mm (but it's not a reducer).Answer by: Jonathan Cheek (Admin) on Aug 23, 2015 4:50:00 PM
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