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Post by Dragon Man on Jan 28, 2015 15:43:33 GMT
Recently I started using a #12 Yellow filter in my Achromat Telescopes again, to help eliminate Violet Fringing, which it does successfully. But I was asked by Rock Mallin of 'Mallincam' could I try the same test but without using the UV/IR filter I often use. I usually take out the UV/IR filter when I use my ED80 as it doesn't seem to need it and if I do use it, it seems to block a percentage of light from Galaxies. But now I am using Achromats again the UV/IR filter really helps with Star Bloat. But Rock asked me to test it, and I did. I was also interested to see what the difference would be. Would the yellow #12 clean the stars up as well as the Violet Fringing? Well, the answer sadly was 'No'. Without the UV/IR filter the stars blew out as they normally do in an Achromat without any IR or UV/IR cut filters. I made an animation to show the difference between the two setups. One with both yellow #12 and the Astronomiks UV/IR 'L' filter, and the other with just the #12 Yellow. You already know the results of the test with and without the #12 Yellow. This one: This new test was to see the difference using the Yellow with and without the UV/IR filter. Here is the result in an animated form. The first frame shows the camera with both filters. The second frames shows the results without the UV/IR filter:
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Post by Dragon Man on Jan 28, 2015 16:18:19 GMT
Another obvious difference can be seen between these two screen grabs. Using Galaxy NGC 4945, this 1st one is with a UV/IR filter: and this is with the UV/IR filter removed tonight: Please remember, these results are for Achromat Refractors, not other styles of telescopes.
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Post by ChrisV on Dec 28, 2015 1:45:35 GMT
The revolution imager I'm using came with an "IR CUT FILTER". I assume this doesn't block UV ? Or does it ...
Should i get an IR/UV blocking filter and use that instead ? Or is one only needed for achromatics. I'm using a C8 SCT.
If so, I'm sure i saw a thread somewhere about which ones were good. But can't figure out where i saw this.
Chris
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Post by ChrisV on Dec 28, 2015 2:09:14 GMT
To modify my above question. I have since actually looked at the rev imager website and it says the filter is a uv/ir filter.
But i seem to remember seeing someone say that not all uv/ir filters are created equal, to quote Orwell. Is this correct ? Should i get a 'better' one. Or am i kidding myself.
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Post by davy on Dec 28, 2015 3:09:19 GMT
The ir filter that is factory fitted is better removed or disabled,the filter supplied in the kit will be of astronomy grade and let in the spectrum of light we require
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Post by ChrisV on Dec 28, 2015 4:32:03 GMT
Thanks Davy. And I should have said, the uv/ir filter supplied is a separate astro filter, it's not the ir filter that's comes in those cameras.
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Post by Dragon Man on Dec 28, 2015 11:12:19 GMT
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Post by Rick in NWArk on Dec 30, 2015 15:21:10 GMT
As with everything in Astronomy, there is not one ________ (in this case, filter) that is perfect for everything.
I really only use mine for Solar and Planetary. I have for a few Nebulae too,
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Post by howie1 on Jan 31, 2016 23:35:55 GMT
Thanks for the comparisons Ken. I spoke to you a while back and you told me about the 'trick' with Achro's to get sharp stars (uv/ir cut + #12). And at the time you mentioned one of the blessings of that solution was that achro's are (relatively speaking) "cheap as chips". Sure are! I bought a skywatcher 120 x 600 which included an eq3 manual mount for $550 new! I have since sold the eq3 mount, so overall it cost me even less than that! Nice f/5.0 for camera work. Thanks for the tips.
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Post by Dragon Man on Feb 1, 2016 4:36:01 GMT
Your welcome Howie
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