Posted Saturday, October 27, 2007
Yesterday I placed and order for a Televue Powermate 2.5 balow. This will replace the Maxpower 1.6x lens for high magnification imaging and will be used for Mars imaging.
Upgrade work continues on the 10" Classical Cassegrain. The new Parallax rings will attach to the Astrola cradle easier than I had thought. I picked up some 3/16" steel plate at the hardware store for fashioning some connector plates that will mate the bottom of the Parallax rings to the ends of the cradle.
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Posted Monday, October 22, 2007
A perfect pair of Parallax rings came up for sale on Astromart, so work on the 10" began again after a short hiatus. The tube was shortened and the finder, tube counterweight and spider were re-attached so now it's looking like the real deal. Re-aluminizing the 26-year old Coulter mirrors and devising a suitable method of attaching the OTA to the Cave Atrola mount are the only tasks left to be done.
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Posted Saturday, September 22, 2007
The DBK 21AF04.AS color 640x480 camera arrived last Thursday and saw first light last night. The moon was very low in the sky and the seeing was horrible, so I attached the camera to the the Mak-Cas for a couple of low power F10 streams. I'm beginning to appreciate Mak-Cas for it's ability to do imaging even though the conditions are bad.
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Posted Saturday, August 18, 2007
A high-resolution black and white camera from The Imaging Source arrived on Wednesday. It is a DMK 31AF03.AS and uses the FireWire interface for fast frame rate acquisition. The camera saw first light last night under very hazy but clear skies. Unlike the TouCam, the DMK can be used for deep-sky photography as well as planetary. Since both Jupiter and Mars were deep in the usual summer haze, I turned the scope to vertical and experimented with exposures of 10-30 seconds, capturing single-frame images of familiar summer objects.
This single frame 30 second grab of M57, the Ring Nebula in the constellation Lyra, was surprising easy to do even considering the terrible seeing conditions. I determined that a single 40 second exposure will show stars beyond magnitude 13, a tough thing to do for an f18 scope. This opens up a new avenue of imaging here at Grenville Base Observatory.
The DMK will be primarily used for Lunar imaging, but should also provide nice B/W images of the planets.
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Posted Tuesday, July 17, 2007
The photo below was taken on July 17 and shows the new blue paint job, the glossy backplate finish and a new Losmandy finder bracket. A new primary mirror baffle has also been installed. I am trying out a somewhat unconventional means of attaching the baffle to the OTA: instead of attaching it to the cell or the inside face of the baffle plate, I have attached it directly to the focuser drawtube. The drawtube, in effect, now extends right through the mirror and nearly halfway to the secondary. one advantage of this approach is to ensure the baffle is perfectly concentric with the focuser axis. The drawtube is light guage metal so it doesn't put too much axial strain on the focuser. Racking in and out will change the field of view at the end of the baffle, but with a focus travel of 3", this shouldn't have much effect on incident light control.
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Posted Friday, July 6, 2007
After being absent for over 3 months being reconfigured from Classical Cassegrain to Dall-Kirkham, the 16" primary mirror and secondary arrived in late June. Needless to say, the weekend before July 4 holiday was spent re-installing and rough collimating the mirrors. Clear (but hazy) skies finally came on Monday night July 2 and a first-light image of Jupiter was obtained.
A solar filter for the 127mm Orion Starmax arrived on Friday, June 29. First views through the filter on July 4 showed a very pleasing golden-yellow orb with a lone sunspot near the middle of the disk.
Prior to the mirror arrival I had three months to attend to small projects related to the scope and observatory. A 12" square mask with a 17" hole in the center was positioned at the center frame of the truss to help block direct light from the sky getting into the optical path. The overall improvement in image quality is probably small. Also, at the backplate of the scope, I attached an aluminum angle with holes in it for use as a means of securing instrumentation at the focuser and also to act as a place to hang the electric focus control box.
The entrance door to the observatory was undercut about an inch and a new threshold was installed. The 3x3 recessed entryway just inside the observatory was fitted with a piece of masonite and a square of indoor/outdoor carpeting.
The restoration of the 10" scope began in April and continues. Yet to be done:
purchase a pair of Parallax rings
construct some kind of adapter out of aluminum to attach the new rings to the old Astrola mount.
Put a new black gloss coat of paint on the Astrola mount. I want to get rid of that old krinkle finish.
send the mirrors out for aluminizing
Re-attach the OTA hardware (counterweight, finder, spider, end ring)