TPO 10" f/8 Ritchey Chretien Reflecting OTA Telescope

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  • Regular price $2,495.00
  • TPO 10" f/8 Ritchey Chretien Reflecting OTA Telescope

    • Sale
    • Regular price $2,495.00
    • ITEM #

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    • Aperture: 10 inch (254mm)
    • Focal Length: 2000mm
    • Focal Ratio: f/8
    • This item Ships FREE Domestically!

    TPO 10" f/8 Ritchey Chretien Reflecting OTA Telescope

    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.

    Optical Highlights: This Third Planet Optics (TPO) Ritchey Chretien telescope has 10 inch (250mm) of aperture and a focal length of 2000mm. 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.

    Multiple Knife-Edge Baffle System: The computer designed and optimized baffle system in the TPO Ritchey-Chretien works wonders at keeping stray light at bay. Inside the tube are nine light baffles, and the primary and secondary mirrors are baffled as well.

    Cooling Fans: The 10 inch Ritchey has three small cooling fans in the rear cell that help cool the inside of the tube down and bring it to ambient temperature so that you can start imaging sooner! The fans are powered by an external battery pack. This battery holder accepts 8-AA batteries (sold separately).

    3.3 inch Dual Speed Fully-Rotatable Crayford Focuser You'll love the 3.3 inch 1:10 Dual Speed Crayford focuser that comes standard on this RC. The dual knobs allow you choose the speed with which you focus. One turn of the larger knob equals ten turns of the smaller knob, so minute adjustments when you are "almost there" are easy to do with this high quality focuser. A 2 inch & 1.25 inch compression ring adapter is also included so you can use both 2 inch & 1.25 inch eyepieces. Two spacers are included as well, which allows you to adjust the focus position for different cameras with various back focus requirements.

    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 Dovetails & Finderscope Base Included Talk about versatility! A Losmandy-style dovetail is attached to the bottom and top of the OTA. The dovetail(s) can be removed if you wish to use mounting rings (sold separately) instead. While a finderscope is not included, the OTA comes standard with a finderscope base that will accept Vixen-style brackets (if you want an optical finder) or most red dot finders.


    TPO Product Number: 10RC-M

    Additional Information

    Aperture254 mm (10")
    Back Focus288mm
    Camera/Eyepiece Connection2" nosepiece
    Dawes Limit0.46 arcseconds
    Focal Length2000 mm
    Focal Ratiof/7.9
    Free ShippingYes
    Glass TypeQuartz
    Hightest Magnification508x
    Limiting Magnitude15.8
    Optical DesignRitchey Chretien
    Secondary Obstruction110mm
    Tube Diameter294mm
    Tube Length650mm
    Tube Weight35 lbs
    Warranty2 Year Warranty

    Questions & Answers

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    • What Cases are available for this OTA?

      Hello John, Thank you for your question. I would say that the best case for this is the Pelican 1660 Case. This case is a hard waterproof case which will protect the telescope well

    • What vixen mount would best handle this OTA?

      The SXD2 will be at its upper-limit, given the 35LBS weight of the OTA. The Atlux will handle it like a breeze!

    • what is the backfocus length of this telescope, and what would it be with a .75X or a .5X focal reducers? Thanks.

      The back focus of this scope at f/8 is 235mm from the rear M117 thread on the rear of the scope. There are no f/5 focal reducers that work with this scope, and the 0.75x TPO is a reducer but not a corrector so it will only work with sensors up to 15mm di

    • Should I be aware of any issues mating this scope with an Orion Atlas EQ-G (manual states 40 lb limit)?

      This telescope has D-series dovetails (4" wide with 2.96" rails), so you will need to have the upgraded saddle from Orion or ADM to accept the wider dovetail. You will also need a minimum of 3x 11lb counterweights and will need to shield the telescope fr

    • Will the Teleskop Service Flattener work with this scope and focuser or will I need to add some adapters to make the connection?

      The TS-RCKORREKTOR is 2" in diameter and will slide right into the focuser like a 2" nosepiece. You will need M48 threaded adapters (2" OD) to get the distance from the flattener to your camera's sensor to 109mm +/-2mm. Please contact us if you have que

    • I don't suppose there's any chance at ordering this OTA without a stock focuser is there? I really don't want to pay for a 3" focuser I'm not going to use. I have a thing for Feathertouches and it seems a waste if it could be avoided.

      All of the TPO RCs come with either the 2" or 3" focuser. unfortunately, we do not sell units that have the focuser excluded.

    • How long is the waiting list if I were to place an order in the next 15 days ?

      Hello and thanks for your question. The lead times vary depending on several factors. Generally we expect 1-3 weeks,