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adequate for a new coating?

Started by gnowell, 04/01/2010 01:55AM
Posted 04/01/2010 01:55AM | Edited 04/01/2010 01:57AM Opening Post
I just got this back from OMI. I know a few pinholes are inevitable but I thought I would ask folks what they think....




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"Scope will get you through times of no money better than money will get you through times of no scope." --Freewheelin' Franklin
Posted 04/01/2010 03:59AM #1
Did you send that photo to OMI?
Posted 04/01/2010 03:36PM #2
Hi Greg,
Well, that would not be good enough for me I am afraid. I would not accept pin holes in my secondary mirror, too much light hits it. Plus, if I pay for a good job I expect it. I would ask them to re coat it. But, will it actually cause a real problem, probably not.

I have not used OMI myself, so can not comment on their practices or communication. I have used L&L Optical for all my coating for the last 6 years. Every mirror looked perfect when they arrived, including secondary mirrors.

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 04/01/2010 04:30PM #3
This looks fine. This is what a good coating should look like.
The effect of the pinholes is highly exagerated by the bright
back lighting. If the entire mirror was covered by hundreds
or thousands of these pinholes you might have an issue,
but 3 or 4 microscopic ones is nothing to worry about.
No matter how good your clean room is, you can't get 100% of the
dust -- theres always a tiny bit that gets in the coating chamber
and leaves pinholes. The bigger question is how the other
99.999% of the mirror surface looks in normal lighting -- if
it looks bright and uniform then you are in good shape.
If there are big blotches or finger prints in the coating, then
it should be done again.
Posted 04/01/2010 04:59PM #4
Greg at least you received your mirror back in one piece. They put a rather large chip in my one of a kind classic cassegrain secondary. OMI pretty much told my to get scr**ed even when they admitted it was chipped in house. Get your money back and take it to L&L for coatings, Floyd gave you some good advice. Martin

"In the beginner's mind there are many possibilities, but in the expert's there are few." Shunryu Suzuki[COLOR="Blue"][/COLOR]