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Old 14-11-2019, 09:05 AM
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alistairsam
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Mirror Testing

hi

I have a 10inch F4 Orion optics standard grade primary mirror and wanted to know if there are any options in DIY testing to get a general idea of the quality of the mirror? or are there any testers in AU that can do the testing?

I came across these
http://www.astrofox.nl/contents/en-u...g-mirrors.html
https://www.instructables.com/id/Opt...bolic-Mirrors/

https://www.teleskop-express.de/shop...th-a-star.html


Thanks
Alistair
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  #2  
Old 14-11-2019, 09:52 AM
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Merlin66 (Ken)
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An easy test you can do is to use a Ronchi grating (https://en.wikipedia.org/wiki/Ronchi_ruling) and observe either an artificial star or a real star reasonable high up.
Any distortions in the observed lines could indicate a problem - either in collimation or the mirror.
http://www.ronchiscreens.com/screens.php
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Old 14-11-2019, 10:47 AM
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alistairsam
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Thanks
will this one do as I have this. its 10lines per mm.

https://www.teleskop-express.de/shop...th-a-star.html

Can I use an artificial star to test as well and do I observe the lines at focus?

Thanks
Alistair
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  #4  
Old 14-11-2019, 11:00 AM
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Merlin66 (Ken)
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Yes,
works with an artificial star (I use the Hubble torch https://www.bintel.com.au/product/hu...v=6cc98ba2045f ) as far as you can position it from the scope...
I use the hallway which is pretty long!
Near to focus, get four or five lines visible and then work closer from there.
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