Homemade Hyperbolic Astrograph - 2, Test Jig.
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Homemade Hyperbolic Astrograph - 2, Test Jig.
Dear Star Shooters,
The test jig of the astrograph has been finished. The aim is to test the dimension prior the construction of the metal OTA. Once metal work has been commenced it is very difficult to correct any design error due to wrong dimensional layout.
Another aim is to test run the optic of the whole design. At the moment a 4 inch f/3.5 parabolic mirror is fitted into the jig. Pictures with and without MPCC were shot using the jig and picture qualities were evaluated to see how good the MPCC could improve the picture quality of this particular f/3.5 parabolic mirror.
Attached please see the results . They are quite interesting.
Best regards
Chan Yuk Lun
1 July 2010.
The test jig of the astrograph has been finished. The aim is to test the dimension prior the construction of the metal OTA. Once metal work has been commenced it is very difficult to correct any design error due to wrong dimensional layout.
Another aim is to test run the optic of the whole design. At the moment a 4 inch f/3.5 parabolic mirror is fitted into the jig. Pictures with and without MPCC were shot using the jig and picture qualities were evaluated to see how good the MPCC could improve the picture quality of this particular f/3.5 parabolic mirror.
Attached please see the results . They are quite interesting.
Best regards
Chan Yuk Lun
1 July 2010.
- 附加檔案
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- Picture shot by the test jig for evaluation. Two such pictures were shot for AB comparision, with and without MPCC. Shot by EOS 5D MK2, crop to approximate EPS-C size, that is , the size of QHY8 ccd.
- 2.jpg (46 KiB) 已瀏覽 8455 次
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- The test jig. The final OTA will have similar dimension. The primary is a f/3.5 parabolic mirror.
- 1.jpg (72.67 KiB) 已瀏覽 8455 次
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
The quailty of picture at central region - Parabolic mirror alone gioves very sharp image at central region, that with MPCC added gives slightly reduced resolution.
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- 100% crop of the central region of the similar picture shot with MPCC added. The resolution is degraded due to under-corrected spherical aberration carried by the MPCC.
- 3b.JPG (20.98 KiB) 已瀏覽 8448 次
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- A 100% crop of the central region shot with a parabolic mirror alone.
- 3a.JPG (21.33 KiB) 已瀏覽 8448 次
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Now AB compare the lower left corner of the picture with and without MPCC. The standalone parabolic mirror produces terrible coma while the MOCC does its job amazingly.
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- 100% crop of similar region of similar picture with MPCC added. Coma much reduced but still exists. With a hyperbolic primary this residue will be reduced further.
- 4b.JPG (19.39 KiB) 已瀏覽 8441 次
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- 100% crop of the lower left corner region of the picture shot by parabolic mirror alone. As expected serious coma occurs.
- 4a.JPG (19.46 KiB) 已瀏覽 8441 次
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
I believe you misunderstood the terms.梅西爾 寫:
鏡神,你是否打算專利用這鏡去觀看彗星(因為先前聽鏡神說採用折射鏡可減低彗形像差 )?
減低彗形像差 does not mean "minimizing the aberration of the comet". and makes it a good telescope for comet observation.
彗形像差 = coma, which makes a star looks like a comet.
Of course, if you can 減低彗形像差, the image will be very good for all types of observations.
PTS
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