The Astro-Tech AT12RC is truly the first affordable 12” true Ritchey-Chrétien astrograph. The AT12RC is supplied without focuser to allow the astro-imager to use an existing focuser or add a premium focuser (FeatherTouch, MoonLite, etc.) of his or her choice.
This Astro-Tech AT12RC Ritchey-Chrétien astrograph has:
• 12" f/8 true Ritchey-Chrétien hyperbolic mirror optical design |
The 12" Astro-Tech AT12RC is the first 12" true Ritchey-Chrétien astrograph available at a reasonable price. Named aSky & Telescope Hot Product for 2011, it joins the line-up of other Astro-Tech Ritchey-Chrétien astrographs that have previously been honored by Sky & Telescope (the original Astro-Tech 6" R-C was named a Hot product for 2009 and the Astro-Tech 8" and 10" R-Cs were named Hot Products for 2010).
And we are serious when we say the 12" aperture AT12RC is “reasonably priced." The Astro-Tech AT12RC is priced many thousands of dollars less than one competitive 12.5" R-C, and still thousands less than another manufacturer’s smaller 10" R-C. As Sky & Telescope pointed out in their Hot Product citation in their January 2010 issue, “Ritchey-Chrétien reflectors are highly regarded among today's elite astrophotographers, and premium instruments often carry price tags starting at about $1,000 per inch of aperture. So it's the best kind of "sticker shock" to see the prices for Astro-Tech's Ritchey-Chrétiens." (The AT12RC is priced at only a third of that per inch of aperture figure.)
The Ritchey-Chrétien optical design is used in virtually every recent large mega-million dollar professional observatory telescope – including the Hubble Space Telescope. The Astro-Tech AT12RC astrograph makes the coma-free imaging of true Ritchey-Chrétien imaging optics available to the DSLR and large format CCD astrophotographer at a price less than that of many large format CCD cameras by themselves and even less than some DSLR camera bodies. Featuring first-quality 99% reflectivity dielectric mirror coatings and premium low thermal expansion quartz mirrors, rather than aluminized Pyrex glass mirrors, this reasonably-priced 12" Astro-Tech R-C makes you wonder just what competitive high-price R-Cs have that makes them cost so much more.
Designed for exceptional imaging, the Astro-Tech AT12RC provides the coma-free photographic field that large format CCD astrophotographers crave, but can’t get from conventional reflectors and Schmidt-Cassegrains. Likewise, as a pure two-mirror system, the AT12RC has a wide spectral response and is totally free from the spurious color that affects the imaging of all but the most costly apochromatic refractors, and it does it with an 12" aperture that dwarfs the light gathering of virtually every commercially-available apo refractor.
In the “Feature Images" section below is a first light AT12RC image of M51 taken by Preston Starr, Observatory Manager of the Astronomy Program at the University of North Texas. Preston shared these comments with us when he sent in the image: “The conditions for imaging were really bad . . . but I thought the AT12RC really performed! Location: ‘Astronomers by Necessity’ observatories; 5 miles southeast of Necessity, TX; 100 miles west of Ft. Worth, TX. Conditions: Poor seeing, poor transparency due to 25~45 mph winds and dust. Telescope: AT12RC F8 (No Field Flattener). Camera: Atik 4000 OSC CCD. Exposure Details: 10 minutes each, 31 images, cooled -15c. Capture with MaxImDL, processed using bias, darks. IP processing by Don Waid." Our congratulations to both Preston and Don for their very good first light image, despite the very poor imaging conditions.
If serious astrophotography is your goal, but the price of most true Ritchey-Chrétien optics has been keeping you from the optical design most modern professional observatories and the Hubble Space Telescope use for their imaging, your wait is over. The 12" Sky & Telescope Hot Product for 2011 Astro-Tech AT12RC astrograph can bring the world of professional DSLR/CCD deep space imaging to your backyard observatory at a truly affordable price.
Features of this Astro-Tech AT12RC Astrograph . . .
Sky & Telescope said that the Astro-Tech R-C’s fixed primary and secondary mirrors “eliminate image shift, which has been the bane of Cassegrain scopes with moving-mirror focusing systems . . . It also keeps the effective focal length of the system constant, and the infinity focal point remains at a fixed point outside of the telescope, neither of which is the case with moving-mirror systems that change the separation between a Cassegrain’s primary and secondary mirrors."
The rear cell of the AT12RC has a male 117m x 1mm pitch threaded port for attaching a focuser. The standard Feather Touch 3" diameter 1.5" travel focuser normally comes with a 109mm threaded collar for connecting to a scope. However, in its #3015 configuration (Feather Touch part #FTF3015B-A), it requires an optional #M117x1 Feather Touch adapter to be used with the AT12RC. The #3015 focuser (without 109mm collar) slips into this adapter and is held in place by three large brass Delrin-tipped retaining knobs. Only focusers with a maximum 1.5" drawtube travel, such as the Feather Touch #3015, are recommended for use with the Astro-Tech AT12RC 12" Ritchey-Chrétien. For brands of focusers other than Feather Touch, such as MoonLite, contact the focuser manufacturer for an adapter to fit the 117mm x 1mm port on the rear of the scope.
To fine-tune the 288mm back focus of the AT12RC to the requirements of your camera and equipment train, two threaded extension rings (each 2" in length) are provided to thread singly or in combination between the 117mm port on the AT12RC rear cell and the focuser of your choice. These provide a flex-free solid metal extension that changes the distance between your chosen focuser and the rear cell. This lets you accommodate the varying back-focus requirements of DSLR-type camera imaging versus long equipment train CCD imaging. Each 2" x 117mm diameter threaded ring weighs 14.4 ounces.
Because of the 41.5 pound (18.9 kg) weight of the AT12RC (without rings, dovetails, or focuser), plus the weight of your ancillary camera equipment and any photoguide scope, installing the AT12RC on a German equatorial mount with a 60 pound (minimum) to 100 pound or greater payload capacity is recommended. Such mounts include the 90 pound capacity Celestron CGE Pro and the Losmandy 60 pound capacity G11 or G11 go-to and 100 pound capacity Losmandy HGM Titan. Other suitable mounts are also available.
Focal Length 2432mm
Focal Ratio f/8
Resolution 0.38 arc seconds
Aperture 12"
Net Weight 43 lbs.
Heaviest Single Component 41.5
Warranty 2 years