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What the heck did I do?

Started by wress, 09/03/2002 05:19AM
Posted 09/03/2002 05:19AM Opening Post
Hi, I'm looking for mirror figuring advice. 16" f5.3, 7/8" plate glass. Prior to figuring session it star tested as undercorrected (based on secondary shadow) quite a bit, and turned down edge (hairy intrafocal image and well defined rings at extrafocal) somewhat. No astigmatism. Did some figuring (45 minutes probably too much), specifically concentrated on the edge using tangential strokes around the perimeter using a 6" lap, and then W strokes across the whole mirror using an 8" lap. Star test afterward looks horrible! Intrafocal looks like a hairy black hole. Almost like a solar eclipse except that all of the edges are blurry. Extra focal is a bunch of sharp well defined rings. Takes forever to get the secondary shadow to show itself. There is also a noticible astigmatism now. Strange thing is that it was able to handle high power focus on the moon better than before. Any ideas? I used a 12" lap to polish it. I'm thinking that I may need to return to it an try to restore the damage I imparted.