TPO 6" f/9 Ritchey-Chretien Astrograph OTA…
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.
6" f/9 Ritchey-Chretien Astrograph Highlights…
Optical Highlights: This Third Planet Optics (TPO) Ritchey Chretien telescope has 6" (152mm) of aperture and a focal length of 1370mm. The concave hyperbolic primary and convex hyperbolic secondary are made from a highly uniform BK7 glass blank, and finished with a scratch-resistant highly reflective 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 eight light baffles, and the primary and secondary mirrors are baffled as well.
2" Dual Speed Crayford Focuser You'll love the 2" 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 1.25" compression ring adapter is also included so you can use both 2" & 1.25" 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.
Vixen-Style Dovetail Rail & Finderscope Base Included A full length Vixen-style dovetail rail is attached to the TPO Ritchey-Chretien optical tube assembly for quick and easy attachment to a Vixen-style mount. The rail 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.
- Additional Information
SKU OS-BLK-6RC Manufacturer TPO Telescope Series TPO Ritchey-Chretien Optical Design Ritchey-Chretien Mount Type Equatorial - GoTo Warranty 2 Year Warranty Telescope Aperture 6" Telescope Focal Length 1370mm Telescope Focal Ratio f/9 Length of Optical Tube 19.1" Optical Tube Weight 12.3 lb. Optical Coatings Aluminum Tube Color or Finish Gloss White Limiting Stellar Magnitude 13.6 Highest Useful Magnification 300x Diagonal Included? No - Sold Separately Finder Included None Manual or Electronic Focusing? Manual OTA Mount Type Vixen-Style Dovetail
- Included Items
- 6" Ritchey-Chretien Astrograph OTA
- (2) M90 x 25mm Spacers
- M90 X 50mm Spacer
- Vixen Dovetail
- 2" Two Speed Crayford Focuser w/1.25" Adapter
- Vixen Finder Shoe
- Dust Caps
- Advanced VX Mount and Tripod
- Celestron 94224 Polar Finder
- Questions & Answers
Product QuestionsI noticed this includes the Advanced VX mount and I am curious if you are modifying the counterweight as the OTA weighs 12.3 and the weight is 12? I have the Advanced VX mount and was considering just purchasing the OTA.Question by: nathan2015 on Dec 17, 2014 7:13:16 AMNo modification of the weight should be needed - the weight will just need to be moved up or down the counterweight shaft until you find the balance point with the RA lock disengaged. The farther from center down the shaft, the more weight the counterweight can balance.Answer by: Chris (Admin) on Dec 17, 2014 9:58:49 AMI'm trying to use an Orion 80 short tube as guider. I need 2 rings (100 to 108 mm OD ?), dovetail plate (for 6" RC) and 2 dovatail adapters. Can you tell me a correct combination ?Question by: JESUS PINEIRO on Feb 2, 2017 8:20:00 PMI've read that rc tunes are not good for regular observing would I need to purchase a 2nd Ota and will I this kit require a autoguiderO AaQuestion by: mike h on Oct 9, 2014 12:42:38 PMHello Mike,
Thank you for your question. It really depends on what you are looking to do with the telescope. If you are looking to use this telescope for visual observation, it might be better to get an SCT or Newtonian optical tube because of their smaller secondary mirrors which translates into an image with more contrast at the eyepiece so it might be more beneficial to get 2 OTAs in this instance. One for observing, & the other for visual.
Autoguiding does make the results of your astrophotos better since it will allow tracking for a longer period of time for deeper & longer exposures.Answer by: Roderick (Admin) on Oct 14, 2014 10:37:14 AM
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