24 in mirror - 18 hrs of parabolizing

自製天文望遠鏡 牛頓望遠鏡 杜蘇式 卡式 設計和磨鏡方法<br>
佛科試鏡法 佛科刀片儀 光柵試鏡法 光柵片
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註冊時間: 週四 09 10月, 2003 21:06

24 in mirror - 18 hrs of parabolizing

文章 Chanlunlun » 週三 31 3月, 2004 00:25

Dear ATMs,

We are also carrying our own null test, except that we don't have a big parabola ( 24 inch ) and so we resort to our own Offner null tester.

We have just corrected the turned down edge and such correction upset the other area of the mirror. A by product of turn down edge correctin is that we again introduce zones at the edge and a small hill also emerges at the center.

Please see attached diagram. As you can see the mirror darkens quite uniformly except that we have very faint zones at the edge and a small hill at center. They will not produce any serious troble as the turned dopwn edge does and we will fix them within the next few days.

We have a feeling that the the figuring will be completed very soon. Who will be that lucky to give the last touch on the mirror to turn it to a perfect parabola?

Best regards

Chan Yuk Lun
The mirror seen under the Offner tester. A central hill and outer subtle high zones. The zones at the edge is very faint. This picture is already enhanced by computer.
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註冊時間: 週六 28 6月, 2003 01:19

文章 Wah! » 週三 31 3月, 2004 00:27



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