LRGB Filter Help

[ribuck]

Hi All,

I just need some help getting my head round LRGB filter setup's. I'm looking at the Baader RGB Filter set on FLO which consists of (RGB + IR Cut Filter).

Now for the baader set, would the IR-Cut filter act as the luminous filter (L) or is the IR-Cut filter just used in conjuction with the RGB filters, i.e. RGB Filters in a wheel, then the IR-Cut on the end of the filter wheel nose piece ?

This brings me onto my next question. assuming that the IR-Cut filter does in fact connect to the nose piece of the filter wheel, how would i then use other filter such as the Baader UHC-S filter at the same time. Would this just be double stacked with the IR-Cut ?

Thanks in advance.

Regards,

Rich.

[GazOC]

The IR-cut can be used stacked with the RGB or on its own as the L channel. The filters are threaded so you can stack them on top of each other.

[ribuck]

So basically,

If i had a filter wheel, I would have the RGB in the filter Wheel, and would then put the IR-Cut Filter on the filter nosepiece stacked with the UHC-S Filter, so that when i wanted to do the Luminous channel i would just select an empty slot on the filter wheel.

Also if i were to stack the UHC-S and the IR-Cut filter, would there be any preference in which order these got stacked ?

Cheers,

Rich.

[Kaptain Klevtsov]

No mate, you use the IR cut filter in the wheel. If you focus using a filter, you need to refocus without one, so the four filters are parfocal and you use any one at a time. I think the Baader RGB filters include IR cut as standard so you don't need to add one.

I've used a CLS filter on the filter wheel nosepiece to good effect as I have loads of light pollution.

Kaptain Klevtsov

[beamer3.6m]

Do filter wheels work well with a Toucam Pro II and the usual nose piece.

[Kaptain Klevtsov]

Do filter wheels work well with a Toucam Pro II and the usual nose piece.

You might have to get creative with the focusing as the filter wheel adds half an inch or so to the outward extension. If you try, screw the filter wheel onto the T thread on the 'scope as this gets you further in that using a nosepiece on the wheel.

Kaptain klevtsov

[Whippy]

No mate, you use the IR cut filter in the wheel. If you focus using a filter, you need to refocus without one, so the four filters are parfocal and you use any one at a time. I think the Baader RGB filters include IR cut as standard so you don't need to add one.

I've used a CLS filter on the filter wheel nosepiece to good effect as I have loads of light pollution.

Kaptain Klevtsov

Would it matter if you have the IR cut on the nosepiece? The one time I've managed to use my RGB set so far I had the IR cut with my IDAS filter on the nosepiece, my thinking being that the at least the red filter would let in IR because I've got the Baader set and I believe that the RGB components don't have IR cut built in, not 100% on it though. They are parfocal though .

Tony..

[ribuck]

Well this is the bit i am confused about. I dont think they have ir blocking built into the filters, and i thought that you would want the IR-block to be used with RGB filters. The reason i say this is becuase when you look at the astronimc filters they have the ir-cut built into each filter, i.e. the rgb are are ir-blocked but with the baader set you would have to have the ir-block filter on the nose piece of the filter whee lto achieve the same effect.

[FLO]

The Baader RGB filters do not incorporate IR block so must be used together with the supplied IR block filter.

[ribuck]

Steve, is it ok to use the Ir block and the uhc-s filter both screwed onto a nose piece at the same time ? and if so do they need to go in any particular order.

[Whippy]

You can and they don't need to go in any order. I'm curious as to why you would use a UHC filter though. Is this for certain nebulae?

Tony..

[ribuck]

They apparently make very good light pollution filters. so that's the main purpose. Apparently better than skglow and neodynium.

[MartinB]

They don't need to be in any order Rich.

Would it matter if you have the IR cut on the nosepiece? The one time I've managed to use my RGB set so far I had the IR cut with my IDAS filter on the nosepiece, my thinking being that the at least the red filter would let in IR because I've got the Baader set and I believe that the RGB components don't have IR cut built in, not 100% on it though. They are parfocal though .

Tony, the IDAS is the one LP filter that has built in IR block.

[FLO]

Tony, the IDAS is the one LP filter that has built in IR block.

Martin, the new Baader Neodymium LP filter also has IR block

[ribuck]

When people say IDAS are they referring to the UHC-S Filter ?

[FLO]

I think they are referring to the IDAS LPS.

[Whippy]

Tony, the IDAS is the one LP filter that has built in IR block.

Really? I was under the impression that some did (later versions?) and some didn't. I bought mine secondhand and I didn't think of asking how old it was. When it gets dark again, I'll have to check this out!

They apparently make very good light pollution filters. so that's the main purpose. Apparently better than skglow and neodynium.

Erm, not sure about about that. AFAIK, UHC filters are narrowband visual filters designed for nebulae. Therefore, they wouldn't be much good for Galaxies, Clusters or anything starlight based. I've heard of someone using one in conjunction with (I think) an IR cut filter to get a similar effect to a HA filter but for general light pollution? No.

When people say IDAS are they referring to the UHC-S Filter ?

An IDAS filter is a light pollution filter made by Hutech. Similar to Astronomik's CLS and Baader's Neodymium.

Tony..

[ribuck]

I presume the UHC-S also works as a good lp filter. steve does it also have iR-Block ?

[GazOC]

A UHC-S should block IR as a matter of course.

[GazOC]

..I think!!

[ribuck]

Gaz am i right thinking it's a form of lp filter used mainly for nebula ?

[FLO]

I think infrared is about 700nm and higher, so 'yes' it cuts IR.

Here's the chart: http://tinyurl.com/58ccof

[GazOC]

Its the best single filter visually for DSOs, it lets through OIII and Hydrogen Beta which improves a lot of nebulae and comes in handy when the Moon is spoiling the view. I'm not sure about its imaging qualities, not really my thing...

[ribuck]

Thanks Steve, was beginning to worry that i had bought the wrong thing, since it's been a while since i bought it and not had a chance to use it.

Luckliy that will all change as my diy observatory will soon be finished, then i can actually start using all the stuff i'e bought.

[FLO]

Like Gaz says, for visual its fantastic but I am not an imager either so if someone could confirm the UHCs and IR block situation, that'd be great

The small chart in that PDF certainly suggests that it does but it is possible that it could let through some higher frequency IR not shown on the chart.

I would Google for more detailed transmission curves but its late and my eyes are glazing so I'm off to bed