The 2" barrel of the fully multicoated dual-element Astro-Tech field flattener inserts directly into your scope's 2" focuser drawtube. This one performs well over a 40mm image circle in all three small RCs (6", 8", and 10")." Here is what he had to say about the #AT2FF, "My conclusion, which seems supported by what users are saying, is that you don't need any other field flattener. An optical analysis and ray tracing of the field flattener was done in ZEMAX and applied to the R-Cs by Roger Ceragioli, the noted optical designer who did the final optimization of the design of the Astro-Tech Ritchey-Chrétiens. Won't image without it," and "Works well with my AT6RC," show up regularly in on-line imaging forums. While not specifically designed to work with Ritchey-Chrétien astrographs, images taken with the field flattener by Astro-Tech R-C owners have shown that the Astro-Tech 2" field flattener works remarkably well with these advanced coma-free reflectors as well as with refractors. For photographers shooting day or night, the flattener is well worth its current $150 price." By focusing at a point slightly off center, thus balancing the imaging performance between the center and edge of the field, I could fill the frame with nice, round star images. At night, star images in the corners of my Nikon D300's APS-format frame, while vastly better than those recorded without the flattener, still showed a slight elongation. Daylight shots made two things immediately apparent - the field flattener does not change the telescope's focal length (it's a true zero-power flattener), and it sharpens images at the edge of the field. You simply screw on the appropriate T-ring, connect your camera, and slip the flattener into the AT106's 2-inch focuser. It is not designed for visual use, having photographic T-threads only and no provision for using a star diagonal or eyepieces.Ī separate review in Sky & Telescope magazine of the Astro-Tech field flattener and the Astro-Tech AT106 refractor said the field flattener was "extremely easy to use with any SLR camera. The flattener was reviewed in the September 2009 issue of Sky & Telescope, page 38."ĭesigned to work purely as a field flattener for imaging, and not simultaneously as a focal reducer or telecompressor, the 2" Astro-Tech field flattener does not change the focal length or focal ratio of your telescope. And there are reports that helps flatten the field of Astro-Tech Ritchey-Chrétien astrographs. Furthermore, it's designed for any refractor with a focal ratio between f/6 and f/8. Custom-designed flatteners usually cost hundreds of dollars, but the Astro-Tech 2" Field Flattener is only $139. The field flattener also works surprisingly well with the 6", 8", and 10" Astro-Tech Ritchey-Chrétien astrographic reflectors.Īs Sky & Telescope pointed out in their Hot Product citation, "With only a few noteworthy (and expensive) exceptions, refractors need optional field flatteners in order to deliver acceptable star images across the field of today's DSLR cameras. You don't have to worry about photos that are sharp in the center but out of focus at the edges. Stars on your images look sharp and point-like all the way across the field. Named a Sky & Telescope Hot Product of the Year for 2010, the Astro-Tech photographic field flattener reduces the normal field curvature inherent in all refractors to provide you with images that are sharply focused out to the very corners of your DSLR or large format CCD imager frame. New for August 2021, thread on adatper tops to choose between 42mm T-threads and 48mm T-threads. iOptron 20% Off Sale While Supplies Last.Various Used and Demo Scopes and Mounts.Astro-Tech AT60ED and AT72EDII Black Friday Sale.Various Closeouts Meade, Kendrick, Bob's Knobs, JMI and others.Astronomics Used, Demo, Closeout, Spring Cleaning Page.Celestron NexStar SE Winter Savings Event.Rechargeable Batteries And Power Supplies.Personal Planetariums / Electronic Sky Guides.Focal Reducer and Field Flattener Combos.Equatorial & Altazimuth Accessories & Adapters.
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