Third Planet Optics (TPO) 8" f/8 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.
8" f/8 Ritchey-Chretien Astrograph Highlights…
Optical Highlights: This TPO Ritchey Chretien telescope has 8" (200mm) of aperture and a focal length of 1600mm. 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 ten 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.
Two Dovetails & Finderscope Base Included Talk about versatility! One Vixen-style dovetail is attached to the bottom of the OTA, while another Vixen-style dovetail rail is attached to the top for quick and easy attachment a variety of mounts. The rails 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.
Please Note: The image shows the carbon fiber version of this telescope. The rolled steel version is white with black metal trim. All other accessories are the same.
About the Celestron Advanced VX Mount…
The Advanced VX equatorial mount from Celestron was engineered from the ground up with astro-imaging in mind, and sets a new standard in mid-level telescopes on the market today. The Celestron Advanced VX provides you with many of the features found on sophisticated German equatorial mounts, at an extremely affordable price.
The Celestron Advanced VX equatorial mount is specifically designed to provide optimum imaging performance for telescopes that weigh thirty (30) pounds or less. With the Advanced VX, you’ll be able to track through long exposures using permanently programmable periodic error correction, or image across the meridian without doing a meridian flip, so you can seamlessly image the best part of night sky. You can also enjoy features like All-Star Polar Alignment and auto guider support. The Advanced VX has a significantly larger base than Celestron's CG5 mount, improving stability under heavy loads. The motors have also been improved. They now offer more torque and can more easily handle slight load imbalances.
Experienced imagers will love taking this portable mount to a dark sky site, knowing that they can experience much of the performance of their larger stationary mount. New amateur astronomers will also benefit greatly from the advanced features of the Celestron VX mount. They can rest easy knowing the mount they have chosen will serve them for a long time to come, whether they wish to do visual or imaging work…or a combination of the two.
- Integer gear ratios and permanently programmable Periodic Error Correction on the Celestron Advanced VX mount eliminates recurring track errors from the worm gear.
- The motors of the VX mount offer improved tracking performance & provide more power to overcome load imbalances.
- The updated industrial design of the Advanced VX offers more rigidity, less flexure and improved aesthetics.
- The Celestron VX design allows viewing or imaging across the meridian without interference from the motors housings.
- The Advanced VX mount can be used between 7 – 77 degrees latitude, incorporating a much larger latitudinal range than normally seen on equatorial mounts.
- The improved electronics on the Advanced VX contain increased memory for future expansion.
- A Celestron NexStar+ hand control offers multiple language programming (English, French, Italian, German, Spanish)
Celestron Advanced VX Mount Specifications…
- Tripod: Adjustable, Stainless Steel
- Tripod Legs: 2"
- Power Supply: Car battery adapter
- EQ Mount Weight: 17 lbs (7.71 kg)
- Total Weight (lbs): 46 lbs (21 kg)
- Tripod Height (Max): 64" in (1626 mm)
- Tripod Height (Min): 44" in (1118 mm)
- Tripod Weight: 18 lbs (8.16 kg)
- Counterweight Bar: 12" Length, 0.75" Diameter lbs (5.44 kg)
- Counterweights: 1 x 11 lbs
- Payload Capacity: 30 lbs (14 kg)
- Latitude Range: 7-77º
- Motor Drive: Low cog DC Servo motors with encoders, both axes
- Slew Speeds: Nine slew speeds, 4 deg/sec maximum
- Tracking Rates: Sidereal, Solar and Lunar
- Tracking Modes: EQ North and EQ South
- Alignment Procedures: 2-Star Align, Quick Align, 1-Star Align, Last Alignment, Solar System Align
- Communication Ports: 2x AUX ports, Autoguider port, RS-232 port (on hand control)
- Computer Hand Control: Double line, 16 character Liquid Crystal Display; 19 fiber optic backlit LED buttons
- Database: 40,000+ objects, 100 user defined programmable objects. Enhanced information on over 200 objects
- Power Requirements: 12V DC 3.5A (tip positive)
- Internal Clock?: Yes
- GPS?: Optional SkySync GPS Accessory
- Additional Information
SKU OS-BLK-8RCM Manufacturer TPO Telescope Series TPO Ritchey-Chretien Optical Design Ritchey-Chretien Mount Type Equatorial - GoTo Warranty 2 Year Warranty Telescope Aperture 8" Telescope Focal Length 1600mm Telescope Focal Ratio f/8 Length of Optical Tube 21.8" Optical Tube Weight 15.8 lb. Optical Coatings 99% Dielectric Tube Color or Finish Gloss White Limiting Stellar Magnitude 14 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
- TPO 8" f/8 RC Steel Tube OTA
- 2" Dual-Speed Crayford Focuser
- (2) "V" Dovetails
- 2" and 1.25" Compression Rings
- Finderscope Mounting Shoe
- Celestron 94224 Polar Finder
- Questions & Answers
Product QuestionsQuestion by: Shawn on Oct 24, 2015 11:51:00 AMAccording to the information available from the manufacturer, the steel version has 96% enhanced coatings and the carbon fiber one has 98%+ dielectric coatings. Functionally, there will not be a real perceivable difference in exposure times through the two scopes.Answer by: Chris Hendren (Admin) on Oct 26, 2015 2:11:00 PM
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