| Here is my latest work in progress. This is a 253mm f/15 Classical Cassegrain by Star Instruments. This is shown in my backyard set-up on the permanent G-11. The OTA is secured using two Losmandy DC-14's sandwiching a pair of Parallax Rings. This provides a relatively stable mounting that can accept my 10" f/4 or 10" f/6 as well. Mounted on the upper Dovetail is the aforementioned Orion guidescope. The set-up as pictured is set with a primary to secondary spacing of 29 3/8 inches and 12 inches of rear focus available. Future enhancements will be addition of a rear mounted cooling fan and an Astrophysics 2.7 inch focuser.
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1st Light Image
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This is the bigger brother to the Celestron 5.5 inch Schmidt Camera. It is 8 Inch and operates at f/1.5. This camera used to be owned by Hans Vehrenberg and has one of the rare Vehrenberg Medium Format Film Holders. With this film holder installed this camera will image a 10 degree circular section of sky. This instrument is mounted, like the others, in a cage constructed of Losmandy Dovetails and Parallax Rings. I have added a Meade Metal Dew Shield. this is shown here on the GM-100. Future changes needed here are a bit of collimation, always fun at f/1.5 and installation of a nitrogen purge to help combat the humid Texas conditions which can spoil Hypered Tech Pan very quickly.
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| Here is the 10 inch f/6. Its an original Parks 253mm f/6 dating from the early 1970's. Minimally modified with the addition of a JMI DX-1 Focuser, the Spyder and Secondary have been replaced with Novak versions and the addition of a rear mounted cooling fan. Dual temperature sensors keep tabs on the thermal stability. One tracks the pyrex mirror's temperature and the other the outside air temperature. The original rotating rings have been removed and the tube assembly rides in the same cradle as the others. Currently this doesn't get a lot of use due to my concentrating on getting the other OTA's functional but this will soon be making the trip to dark skies also. This only fits in the car by riding in the passenger seat with the seat back lowered as far as possible.
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Latest addition to the arsenal of equipment. This is a Takahashi
FSQ160N outfitted with a Pentax 6x7 Camera Body and a Hutech vacuum
back. This combination sits atop an early Christmas present to myself,
a slightly used Astro-Physics AP900 Mount. This mount came with a 53 inch
pier which is a bit tall and I will probably replace it with something
much shorter. This image is from its first trip to Ft Griffin and while
conditions were far from ideal the combination was rock solid and every
image turned out fine. Wind was gusting 35 Mph and temps were in the low 30's
making this a very cold night indeed.
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| After 3 years on the waiting list my name finally came up for an AP1200GTO mount.
Here it is mounted onto my homemade pier in my observatory. It replaced a G-11/Gemini
and will provide more payload capacity and better results when used robotically. Shown
with the 253mm f/6 Newtonian mounted on it with the SBIG STL1100M. Initial tests with this setup
have been promising and with the Televue Paracorr the corners are improved. I still need to
replace the focuser with something a little beefier and a bit taller, or perhaps an Instrument Rotator mounted against the tube and the focuser mounted on that.
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I had been looking at these instruments for quite some time and when the opportunity came to acquire this gently used 253mm f/9 RCOS Ritchey Chretien I jumped at the chance. While it doesn't provide the same FOV that it's bigger brother, the 12.5 inch, does I have been very pleased with the initial tests. Flat Fielding sorts things out nicely and the lack of Coma is exteremely nice. This is shown here during it's first light mounted on the AP900. A link to the First Light Image is Here Not a spectacular image given the Full Moon but the stars look good across the full frame so it's a good start.
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