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Hardware:
This was the imaging set-up I used until 1st Qtr 2009, a Takahashi FRC-300 Ritchey-Chretien. I picked up the FRC in a trade about 18 months ago, and have been very happy with it. It is built like a tank (so typical of Takahashi) and is capable of producing some excellent images - much better than my limited imaging abilities and the local seeing conditions will usually let me demonstrate. But on those rare occasions when everything works out just right, the scope shows what it is capable of. With a focal length of 2340 mm, it produces an nice flat image circle of 90 mm, and an image scale of 0.79 arcseconds per pixel using a camera with 9 mircon pixels. Speaking of cameras, you might notice that my set-up seems to be missing an imaging camera. I am waiting for a new Kodak 16803 chip camera, which should be available in May of 2007. The guide scope sitting on top of the FRC is a Takahashi FS-78, another wonderful Takahashi scope, and a great guidescope. I've used a Borg Mini45ED and a Takahashi FS-60 as guidescopes in previous configurations, but I like the addition focal length offered by the FS-78. The guiding camera duties are handled by a Starfish guider from Fishcamp Engineering. The Starfish was a new product that began shipping in January of 2007, and I think mine was one of the first production units sold. It seems to be very sensitive and with a 1.3 megapixel CMOS chip and 5.2 micron pixels, it provide a large 33 x 42 arcminute field of view and an image scale of 1.96 arcseconds per pixel with the FS-78. The Starfish is very well made (excellent fit and finish) has done everything I've asked of it so far, even helping to touch up the collimation of the FRC. It is just a bit of icing on the cake that the beautiful red finish matches the Paramount so well - this little camera is a keeper. The imaging camera will be focused by a Clements 4.25" Bellerophon focuser using a Robofocus. If this is your first time seeing a Clements focuser, you need to check the web site out. This focuser is simply amazing! It is smooth and accurate, seems unaffected by any reasonable load (a very important feature given the size and weight of the cameras being built these days). It produces the best v-curves in FocusMax that I've ever achieved with this scope. Adding the Clements focuser achieved two important objectives for me. First, it replaced the standard Takahashi helical focuser, which was a fine focuser, but not very CCD or remote operation friendly. Second, the large 4.25" aperture of the Bellerophon lets me move the corrector element to the camera side of the focusing device and "fix" the metal-back distance to the CCD chip. It is a very sweet set-up, and has a distinctive appearance that really grows on you the more you use it. Don Clement was a joy to work with, and made all the custom adapters needed make the focuser fit. Finally, I've adapted one of Don Goldman's TAKometers and a Takahashi 4" Camera Angel Adjuster (CAA) to the set-up to provide the ability to rotate the camera. This lets me frame the object I'm shooting and provides the opportunity to improve the image composition (we'll have to see if that helps me at all). All the custom adapters needed to attach the TAKometer and CAA to the focuser/corrector and the camera, while maintaining the proper 106.2mm metal-back distance, were made by Ashley Stevens at PreciseParts.
This site was last updated 05/17/09 |
