The making of 26 inch Cassegrain - 11, secondary mirror done
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The making of 26 inch Cassegrain - 11, secondary mirror done
Dear ATMers,
While it took more than a year to finish the 26 inch primary mirror, it took only one day to complete the secondary convex mirror. Our students are really exhausted in grinding, polishing and figuring the primary mirror and hence the secondary mirror was done by me solo.
The secondary mirror of a Cassegrain telescope is convex and hyperbolic in shape. I have polished the mirror but do not have a chance to put it into optical test. There is no practical shop test for a hyperbolic convex mirror except star test. Hence the figuring of the secondary will not be carried out until the finishing of all mechanical parts of the telescope.
The diameter of the secondary mirror is nearly 10 inches, already bigger than some primary mirrors in amateur telescopes.
Best regards
Chan Yuk Lun
13 Oct 2014
While it took more than a year to finish the 26 inch primary mirror, it took only one day to complete the secondary convex mirror. Our students are really exhausted in grinding, polishing and figuring the primary mirror and hence the secondary mirror was done by me solo.
The secondary mirror of a Cassegrain telescope is convex and hyperbolic in shape. I have polished the mirror but do not have a chance to put it into optical test. There is no practical shop test for a hyperbolic convex mirror except star test. Hence the figuring of the secondary will not be carried out until the finishing of all mechanical parts of the telescope.
The diameter of the secondary mirror is nearly 10 inches, already bigger than some primary mirrors in amateur telescopes.
Best regards
Chan Yuk Lun
13 Oct 2014
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- The polished secondary mirror, its diameter is about 10 inches.
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最後由 Chanlunlun 於 週一 13 10月, 2014 21:23 編輯,總共編輯了 1 次。
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- 夸克星
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- 註冊時間: 週四 09 10月, 2003 21:06
The primary mirror will be seated on a 27 points floatation cell.Patshek 寫:There is sophisticated mirror cell for large primary mirror.
However, is there any mirror cell that is designed for secondary? What kind of design will be used on your secondary which is as large as primary?
The secondary will be installed on six point fixed mirror cell. The secondary mirror works quite unlike the primary - its surface always face downward and so theweight of the mirror always acts away from the mirror cell, just contraray to the primary mirror.
Hence the secondary mirror cell could be made in a simpler fashion.
Re: The making of 26 inch Cassegrain - 11, secondary mirror
Chanlunlun 寫:Dear ATMers,
While it took more than a year to finish the 26 inch primary mirror, it took only one day to complete the secondary convex mirror. Our students are really exhausted in grinding, polishing and figuring the primary mirror and hence the secondary mirror was done by me solo.
The secondary mirror of a Cassegrain telescope is convex and hyperbolic in shape. I have polished the mirror but do not have a chance to put it into optical test. There is no practical shop test for a hyperbolic convex mirror except star test. Hence the figuring of the secondary will not be carried out until the finishing of all mechanical parts of the telescope.
The diameter of the secondary mirror is nearly 10 inches, already bigger than some primary mirrors in amateur telescopes.
Best regards
Chan Yuk Lun
13 Oct 2014
這樣是否說明project轉成Classic Cassegrain?
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Re: The making of 26 inch Cassegrain - 11, secondary mirror
Yes you are correct.bbsdma 寫:Chanlunlun 寫:Dear ATMers,
While it took more than a year to finish the 26 inch primary mirror, it took only one day to complete the secondary convex mirror. Our students are really exhausted in grinding, polishing and figuring the primary mirror and hence the secondary mirror was done by me solo.
The secondary mirror of a Cassegrain telescope is convex and hyperbolic in shape. I have polished the mirror but do not have a chance to put it into optical test. There is no practical shop test for a hyperbolic convex mirror except star test. Hence the figuring of the secondary will not be carried out until the finishing of all mechanical parts of the telescope.
The diameter of the secondary mirror is nearly 10 inches, already bigger than some primary mirrors in amateur telescopes.
Best regards
Chan Yuk Lun
13 Oct 2014
這樣是否說明project轉成Classic Cassegrain?
The telescope will become a classical Cassegrain.
-
- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
-
- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
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