Log in

View Full Version here: : LRGB with L being only IR blocking


TheCrazedLog
03-05-2015, 11:51 AM
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

alocky
03-05-2015, 12:19 PM
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.

Amaranthus
03-05-2015, 12:35 PM
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.

LewisM
03-05-2015, 01:11 PM
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

gregbradley
03-05-2015, 01:44 PM
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.