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wenjha
newbie
Reged: 09/24/08
Posts: 2
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Hi, all
I did star test for my 4 telesecopes.those reflector mirrors are made by my friend Mr Wong.
Mr Wong test mirror using double-pass autocollimator null test,here is the equipment:
and here are the Foucault Images of Parabolic 150F9:
he estimated the PV surface error as below :
Parabolic 150F9: 1/20 PV surface error
Spherical 150F9: 1/10 PV surface error
Parabolic 150F5: 1/10 PV surface error
I did star test:
star test is the only test method for me . all pictures are taken using a 3x barlow lens, a extendtube added for 150F5.
the star test result of 150F9 is more beautiful than 150F5 for F9 is more easy to collimate than 150F5, I am sure that the astigmatism of 150F5 is because of the misalign of secondary.
here also some plantary images taken by Spherical 150F9:
Spherical 150F9 is very good for me now. but I still want to know the actual PV error of each mirror.
can we estimate the PV value from the star test result?
Edited by wenjha (09/30/09 09:59 AM)
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WahHK
sage
Reged: 02/24/06
Posts: 308
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It seems that the 150F9 is nearly perfect symmetric, what is the max PV error for a mirror that can produce similar result?
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http://wahwah.dyndns.org:8080/gallery/main.php
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wh48gs
sage
Reged: 03/02/07
Posts: 458
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Quote:
I am sure that the astigmatism of 150F5 is because of the misalign of secondary.
Misalignment in the Newtonian doesn't induce astigmatism.
It is produced by surface deformation, either from fabrication process or improper mounting.
Vla
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wenjha
newbie
Reged: 09/24/08
Posts: 2
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Quote:
Quote:
I am sure that the astigmatism of 150F5 is because of the misalign of secondary.
Misalignment in the Newtonian doesn't induce astigmatism.
It is produced by surface deformation, either from fabrication process or improper mounting.
Vla
Hi I met astigmatism in 150F9 too, but I corrected it by aligning the secondary
what important is that can I estimate the mirror error from star test?
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