A quick question on CCD LRGB imaging

[Astroboffin]

Hi,

A quick question for the imaging pros out there, when I get round to doing some LRGB, with my Atik 414ex mono camera, as I live in a fairly light polluted area I have always used a very good LP filter with my DSLR, so to the question,

Do I still need to use a LP filter when imaging LRGB, with each coloured filter in turn ? Or not

Regards

AB

[johnrt]

You can, I found it improved my images greatly, I use an IDAS LP2 in front of my Baader LRGB.

[Uplooker]

Short, answer yes. The only thing that is different in using the Baader LRGB filters is that they block IR. So yes, have the LPR filter at the front of your imaging train for for all filters.

I speak as if I am an expert, I am soon to start on the path of using a mono CCD. I am looking forward to being able to do Ha imaging when the moon is out

[steppenwolf]

I would recommend a Hutech IDAS LP filter for LRGB work and for the Luminance channel, you can do away with the actual L filter as the IDAS has a built in IR filter but this will also stop the L channel from being parfocal with the others - a small price to pay!

[Astroboffin]

So where is best to put the LP filter in the imaging train, front or back of coloured filter?

AB

[lensman57]

Hi,

A quick question for the imaging pros out there, when I get round to doing some LRGB, with my Atik 414ex mono camera, as I live in a fairly light polluted area I have always used a very good LP filter with my DSLR, so to the question,

Do I still need to use a LP filter when imaging LRGB, with each coloured filter in turn ? Or not

Regards

AB

If your light pollution is heavy then there is no choice. I once voiced my concern over the enthusiasm of some of the members to convince newcomers to AP to do LRGB without consideration of the sky background ADU ( you really do need dark skies for LRGB ) and the LP level and I had my wrist slapped in a very polite way. But my experience with RGB imaging although limited taught me that the IDAS had to stay on the front of the FF/FR otherwise it was gradient galore.

A.G

[Uplooker]

I stand to be corrected, but based on Steve's reply, I would have the LPR at the front and leave the luminance filter out of the FW.

Ian

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[wuthton]

Yup, screw your filter of choice into the nosepiece/ff-fr. I leave mine there full time.

[Uplooker]

Hi AB,

Make sure that whatever LPR filter you use make sure it blocks IR

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[Astroboffin]

Hi AB,

Make sure that whatever LPR filter you use make sure it blocks IR

Sent from my Fone

Well ATM I only have the Baader Neodmynium filter for LP, (it has IR block) so hope that will do the job, as i can't afford another one yet, I would say my LP is little more than moderate but not heavy, and there are no street or spot lights in sight from my viewing area of the garden.

Thanks for all the replys, appreciate them.

AB

[SteveA]

Despite the obvious benefits that the use of these filters brings, I've seen comments regarding serious internal reflections that can be generated through the use of these. Are there any particular imaging setups that are better suited to the use of these ...or indeed any that are not well suited?

[Uplooker]

Hi Steve,

Can you clarify which filters you are referring to LPR or LRGB filters?

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[ollypenrice]

If your light pollution is heavy then there is no choice. I once voiced my concern over the enthusiasm of some of the members to convince newcomers to AP to do LRGB without consideration of the sky background ADU ( you really do need dark skies for LRGB ) and the LP level and I had my wrist slapped in a very polite way. But my experience with RGB imaging although limited taught me that the IDAS had to stay on the front of the FF/FR otherwise it was gradient galore.

A.G

Why would LRGB be any different from OSC? (Apart from the speed advantage of LRGB.) The point being that RGB and OSC are more or less the same thing, though to my mind RGGB (ie OSC) is not likely to be as productive as RGB. Now a mono camera with narrowband filters is clearly going to be the best way to beat LP but that's a different kind of imaging. In heavy LP I would do narrowband with a mono camera and forget broadband natural colour, though there are heros who manage it!

Olly

[Sp@ce_d]

and a reminder for anyone contemplating the Hutech IDAS LP filters (they really are the best in my opinion). If you're going to leave them in front of your mono CCD LRGB/NB set as I do, then you need the P2. The D1 is for OSC/DSLR, (although I used a P2 quite happily before the D1 came out) otherwise you'll have to remove it when using your NB filters as it cuts too far into their emission lines.

[SteveA]

Hi Steve,

Can you clarify which filters you are referring to LPR or LRGB filters?

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Hi Ian,

I was referring to the LPR filters, specifically the IDAS filters that Steve R recomended in this thread. There's a review on the FLO page for the IDAS P2 filters, that really slates these. I realise that negative reviews do have a habit of taking prominence, but there does seem to be a potential issue. just wondered what the SGL thoughts were on this?

[Uplooker]

Hi Steve,

Thanks, I understand your point now. I have read similar points from people about reflections. I personally use an 2" Astronomic LPR filter but am unable to comment on the issue of reflections

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