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Old 03-05-2015, 10:51 AM
TheCrazedLog
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LRGB with L being only IR blocking

Hey all:

I've just got my greedy little hands on an Atik 4000 2nd hand (thanks CoolhandJo!). I've plugged in the various Meade CCD Interference 1.25 filters (that came with a Meade DSI... 2 I think) I have and have noticed that the clear filter is just IR, not IR/UV.

Question is: Can I do LRGB using just IR blocking on the L channel?

Thanks

Anthony
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Old 03-05-2015, 11:19 AM
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alocky (Andrew lockwood)
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Shouldn't be an issue if your imaging scope is a reflector, but if you have refractive optics you may well get some bloating of your stars due to the dispersion at the uv end. Only one way to find out, and I don't think you'll break anything by trying. Be nice to hear back what happens!
Cheers,
Andrew.
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Old 03-05-2015, 11:35 AM
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Amaranthus (Barry)
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If they're the ones I got originally, those Meade filters are pretty limited. The R, G and B filters don't have IR block, so you'd have to use the L in series with the colour filter - not very desirable.

If you want some cheap but still quite high quality LRGBs, go with the ZWO ones. I used these for quite a while (before upgrading to Astronomiks) and still use them for planetary imaging.
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Old 03-05-2015, 12:11 PM
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LewisM
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I have Baader LRGB/Ha in 1.25". I put a uv/ir cut filter on the front of the filter wheel AND an IDAS LP filter (both 2") and notice no negative effect at all. In fact i find a better overall balance than i ever got with astronomiks
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Old 03-05-2015, 12:44 PM
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gregbradley
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I have a clear filter which I used for a while to get that little extra light. Generally it meant slightly bloated brighter stars. I was using a Tak BRC 250 which is a mirrored RC scope with a lens corrector (doublet or triplet corrector not sure which now).

The plus is you get a little bit more light.

Greg.
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