TPO 10" f/8 Ritchey-Chretien Truss Tube OTA

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TPO 10" f/8 Ritchey-Chretien Truss Tube OTA
Item # OS-10RC-TT
  • The TPO 10" f/8 Ritchey-Chretien Truss Tube Astrograph OTA is a true RC scope, and will give you spectacular results when imaging with large format sensors!
  • The included 3" dual speed linear bearing Crayford style focuser is strong and smooth, and comes with a 2" and 1.25" adapter plus extensions for adjusting back focus.
  • The 10" concave hyperbolic primary and convex hyperbolic secondary mirrors are made of quartz, with all its low expansion properties, and 99% dielectric coatings cover the mirrors so the surface will be protected and highly reflective.
  • The trusses are made of carbon fiber and are designed to keep your optics collimated regardless of where the telescope is pointing! Three cooling fans in the rear cell help keep the telescope's temperature constant, resisting focus fluctuations due to temperature changes.


About Ritchey-Chretien Telescopes

In 1910, American optician & astronomer George Willis Ritchey & French astronomer Henri Chretien designed a specialized Cassegrain that would later become the telescope of choice for many observatories and professionals around the world. The Ritchey-Chretien astrograph has many benefits that make this design appealing to anyone who is serious about astro-photography or imaging. Here are a few of those benefits:

  • Good-bye Coma: An RC has virtually no coma (stars look like little comets around the edges of the field), which means there will be greater image quality across a wider field of view.
  • No Chromatic Aberration: Because a Ritchey-Chretien does not use lenses or corrector plates, the design does not suffer from chromatic aberrations, or false color. If you've ever looked through an achromatic refractor (non-APO), you will have seen chromatic aberration.
  • No Spherical Aberration: The use of hyperbolic mirrors for both the primary and secondary removes the problem of spherical aberration from this optical system, an optical effect caused when light rays do not all come to focus at the same point, resulting in an image that is not in perfect focus.

10" f/8 Ritchey-Chretien Truss Tube Astrograph Highlights…

Optical Highlights: This Third Planet Optics (TPO) Ritchey Chretien telescope has 10" (254mm) of aperture and a focal length of 2032mm . 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.

Carbon Fiber Truss Tube Design:

Lightweight yet strong carbon fiber truss tubes have low thermal expansion characteristics. Shifts in focus due to temperature changes are minimized because of this design. The trusses are also designed to flex equally, keeping the optics in collimation regardless of the position of the telescope.

Cooling Fans: The 10" Ritchey has three small cooling fans in the rear cell that help create an ambient temperature within your telescope for more stable viewing and less fluctuation in focus. The fans are powered by an external battery pack. This battery holder accepts 8-AA batteries (sold separately).

A Fixed Primary Eliminates Image Shift Schmidt-Cassegrain & Mak-Cassegrain telescopes achieve focus by moving the primary mirror back and forth inside the optical tube assembly, and this movement can cause image shift. While manufacturers have done a pretty good job of minimizing image shift on their telescopes, a moveable mirror makes it almost impossible to eliminate it completely. The Ritchey-Chretien has a primary that is fixed in place, removing the possibility of image shift and also the job of collimating the primary.

Two D Style Losmandy Dovetails Included Talk about versatility! Two Losmandy-style dovetails are attached to the truss tube support rings so that they ride at the top of the scope as well as at the bottom.

TPO 3" Focuser A 3" dual-speed linear-bearing Crayford-style focuser rounds out this package. The ridged focusing knobs are easy to turn, even with gloves on, and the 10:1 microfocusing dial allows for very small changes, or tweaks, in focus. It takes ten turns of the microfocusing knob to equal just one turn of the larger knob. There is also a little knob on the bottom of the focuser that controls the tension, so that you can make adjustments depending on the weight or distribution of your load. The 3" opening steps down to a 2" compression ring adapter, and you will receive 1.25" compression ring adapter so that you can make use of all your eyepieces. Two 25mm and one 50mm extension tube is also included to help you match the back-focus requirements of your imaging equipment. This is one nice focuser, and due to its steel drive rail and other upgrades, you will find that it suffers from very little flexure, even under heavier imaging payloads.

Long Back Focus of 235mm allows you to mount lots of imaging gear!

Additional Information

Additional Information

Manufacturer TPO
Telescope Series TPO Ritchey-Chretien
Optical Design Ritchey-Chretien
Mount Type None - Optical Tube Only
Warranty 2 Year Warranty
Telescope Aperture 254mm
Telescope Focal Length 2032mm
Telescope Focal Ratio f/8
Optical Tube Weight 35 lb.
Optical Coatings Fully Multi-Coated
Tube Color or Finish Carbon Fiber
Diagonal Included? No - Not Required
Focuser Size 3"
Focuser Style Crayford
Finder Included None
Manual or Electronic Focusing? Manual
Focusing Speeds Two-Speed
OTA Mount Type Losmandy-Style Dovetail

Customer Reviews 2 item(s)

This is an awesome telescope for astrophotographs. It seems to have the correct balance between focal lenght and aperture for CCDs.
I use and recommend TPO reducer 0.8x. The set has round stars from side to side in a 8300 CCD.
Ive never used the fans and focus hold all night.
An incredible scope for the price.
1= Houston, We Have a Problem & 5= It's Out of This World
Review by PCacella / (Posted on 6/22/2015)
Great scope for the price
This scope is beautiful, great fit and finish. Scope maintains collimation and is very easy to setup with provided spacers and mammoth focuser. Really a great value for the price. You get a dust cover for the secondary, but no cover for the primary. You also do not get any documentation. It would be nice to get both.
1= Houston, We Have a Problem & 5= It's Out of This World
Review by Price / (Posted on 8/6/2014)
Included Items

Included Items

  • TPO 10" f/8 Ritchey-Chretien Truss Tube OTA
  • 3" Crayford Focuser
  • Two Losmandy D Style Dovetails
Questions & Answers

Product Questions

Is there a focal reducer available for the 10-inch Ritchey?
Who manufactures this telescope? 
Are your scopes the V2 version with the focuser split from the mirror cell?
What is the spec on the mirrors on the TPO RC truss (for example 1/10 wave)?
Will this scope fully Illuminate a PL09000?
Could you please provide the physical dimensions of the OTA in terms of length, width and height. Thank you>
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