Old 03-05-2015, 11:51 AM
Registered User

TheCrazedLog is offline
Join Date: Dec 2006
Location: Newcastle
Posts: 92
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?


Reply With Quote
Old 03-05-2015, 12:19 PM
alocky's Avatar
alocky (Andrew lockwood)
PI popular people's front

alocky is offline
Join Date: Aug 2010
Location: perth australia
Posts: 1,290
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!
Reply With Quote
Old 03-05-2015, 12:35 PM
Amaranthus's Avatar
Amaranthus (Barry)
Thylacinus stargazoculus

Amaranthus is offline
Join Date: Jan 2014
Location: Judbury, Tasmania
Posts: 1,203
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.
Reply With Quote
Old 03-05-2015, 01:11 PM
LewisM's Avatar
Novichok test rabbit

LewisM is offline
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,096
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
Reply With Quote
Old 03-05-2015, 01:44 PM
gregbradley's Avatar
Registered User

gregbradley is offline
Join Date: Feb 2006
Location: Sydney
Posts: 17,154
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.

Reply With Quote


Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +10. The time is now 03:57 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Limpet Controller
NexDome Observatories
Astronomy and Electronics Centre