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Nassau Station A New Secondary Mount for the NSRTThe ProblemSince the recommissioning of the NSRT direct imager you might have noticed some odd streaking that occurs in long exposures. For example look at this image of the Eagle Nebula: The star images are oblong along an axis from the upper left to lower right of the frame. We had also noticed some rather large errors in the telescope pointing that could not be explained a simple instrumental flexure. The telescope is big and heavy but it is built like a battleship thanks to the Warner & Swasey Company so we did not expect the pointing to deflect as far as it appeared to from the telescope sagging as it points closer to the horizon. A competing problem with the telescope tracking kept us from figuring out what was going on until we had the clock drive and telescope balance fixed. At that point we discovered this image smearing and large apparent flexure errors were due to a wobble in the secondary mirror mount on the telescope.
This problem was not an issue before we installed the electronic camera because the movement of the image plane caused by the floppy mirror would have minimal impact on the cassegrain spectrograph or naked eye observations. The Old MountThe New MountThe plan is to have this new mount constructed and installed by May 1, 2002. Pictures from the installation are online at personal/martin/photos/NSRTApril2002. ©2002 CWRU Astronomy Dept. comments Last modified April 9, 2002 Case Western Reserve University |
© 2003 CWRU Astronomy Dept. |