TPO 16" f/8 Ritchey-Chretien Truss Tube Telescope

  • Sale
  • Regular price $6,995.00
  • TPO 16" f/8 Ritchey-Chretien Truss Tube Telescope

    • Sale
    • Regular price $6,995.00
    • ITEM #



    • Aperture: 16 inches
    • Focal Ratio: F/8
    • Focal Length: 3250mm
    • Optical Design: Ritchey Chretien

    TPO 16" f/8 Ritchey-Chretien Truss Tube 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 16 inches (406mm) of aperture and a focal length of 3250mm. 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 16 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).

    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 inch Focuser A 3 inch 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 inch opening steps down to a 2 inch compression ring adapter, and you will receive 1.25 inch 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 260mm allows you to mount lots of imaging gear!


    TPO Product Number: 16RC-TT

    Additional Information

    Aperture406 mm (16")
    CoolingFans/ Includes 3 small
    Focal Length3250mm
    Focal Ratiof/8
    Free ShippingYes
    Optical DesignRitchey Chretien
    OTA Mount TypeStyle Dovetail
    Warranty2 Year Warranty

    Questions & Answers

    Ask a Question
    • is there a dedicated field flattener for this scope?

      Not yet, but we're working on one. Stay tuned!

    • What is the size and thread pattern on rear rings? I would like to add an auto focus.

      The 16RC-TT uses the same M117x1 thread as the 10, 12, and 14" TPO RC models. Many manufacturers who make focusers have adapters to this thread size, and even if there is not an off-the-shelf adapter for the focuser you want to use, please contact OPT an

    • How large is the central obstruction ... Size of secondary mirror

      The secondary mirror obstruction for the TPO 16" RC Truss is 7.5"

    • hi there, I am very keen to buy this one soon. just few doubts.. What kind of mount I need for that? or how much for the mount if I buy separately. is this good for deep sky imaging? I live in New Zealand. can I buy this one here if any related deale

      The 16" RC-TT is 82 lbs (37kg), and will tip the scales at over 90 lbs once the focuser, camera, threaded spacers, adapters and finderscope are added - not to mention any piggyback guidescope. Generally, we recommend getting a mount rated for at least 1

    • What is the width of the truss tube where it would attach to a fork mount?

      The telescope has a Losmandy D-style dovetail on two sides (normally top and bottom on an EQ mount, but you can rotate 90 degrees to attach to a fork with a D-style saddle on each side). From the narrow base of the dovetail where it meets the shoulder of

    • What is the length of the telescope from front to rear face, not including the focuser? Would be great if you could post a diagram with dimensions. Need to make sure it can fit inside roll-off observatory.

      The 16" TPO RC is 45.5" (1156mm) long without focuser. The supplied focuser adds 5.25" (133mm) with the drawtube retracted. The center and rear truss tube support rings are 22.5" (572mm) in diameter, while the front support ring is 19.75" (502mm) in diame

    • What is the length of the telescope from front to rear face, not including the focuser? Would be great if you could post a diagram with dimensions. Need to make sure it can fit inside roll-off observatory.

      Good afternoon, the manufacturer reports that the scope is 45.5" from the front support ring to the end of the focuser mounting collar.

    • What is the back focal length?

      The back focus for the TPO 16" RC is 260mm.

    • What is the weight?

      The TPO 16" RC weighs 77 pounds.

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