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Omega Optical CaH filter

Posted: Sat May 12, 2018 8:00 am
by GreatAttractor
I was browsing through Omega Optical filters on Ebay and noticed this:

Optical Filter Astronomy 396.9SC0.2 Ca H filter 1.25"

(full description: link)

CaH with 2 Å bandwidth and 90% transmission for $300. Seems promising, what do you think?

Re: Omega Optical CaH filter

Posted: Sat May 12, 2018 1:50 pm
by Merlin66
I’m trialing a stacked combo of three Omega CAK filters (see my other thread)
So far the results have been promising.viewtopic.php?f=9&t=23536

Re: Omega Optical CaH filter

Posted: Sun May 13, 2018 2:07 pm
by Merlin66
Why?
They work for me......

Re: Omega Optical CaH filter

Posted: Mon May 14, 2018 12:14 am
by Valery
My experience with Omega is rather poor. The filter he sent me is the worst optical detail I have ever saw.

Here is this filter unevenness in CWL. I stacked it with Lunt etalon.


Valery

Re: Omega Optical CaH filter

Posted: Mon May 14, 2018 6:55 am
by Montana
I have one of those, it is optically clear but I didn't see much difference with it. I don't use it anymore.

https://www.flickr.com/photos/alexandra ... 0715279858

I must admit I tried it with the SCT and the Baader solar film and I couldn't see anything at all, does Baader film cut below 400nm? it works great with the solar wedge. I can sell you mine for a cheap price if you like? but you probably don't want it :)

Alexandra

Re: Omega Optical CaH filter

Posted: Mon May 14, 2018 7:50 am
by Merlin66
Alexandra,
The ND 3,8( or the ND 5) filtering extends into the UV.....
Just not enough light getting through to the filter - as you say, works well with the wedge.

Re: Omega Optical CaH filter

Posted: Mon May 14, 2018 4:45 pm
by GreatAttractor
Thank you everyone for input. CaK imaging is a plan for the future anyway, it's Hα for me right now.