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Horsehead in Ha


alaskacam

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Dave.. It's the standard Ha filter that comes with the Baader filter set sold with the SBIG STL. I'm not sure how wide the band pass is on this filter. When I finally make the leap to the full narrowband set I'll probably get the Astrodon filters, but still reading up as they can be quite pricy. I'm going to get the remote guide head set up on a second scope before I get the new filters.

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As 3's mobile coverage is attempting to stop me from posting this for a third time lol..

In my view this is POW. It has a real 3D feel around the head - the only thing bad is that there's not a large version of it to see deep into the filaments :D

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It is indeed a pest that you can't get the fine detail to show in LRGB as you can in NB. However, I remain a fan of LRGB or LHaRGB/HaRGB for some reason. It just 'does it for me' when pure tricolour NB simply doesn't. You also get tiny stars in NB and you've split Alnitak there.

Anyway, a great shot. I think you've stretched the upper part of the signal more than is usually seen - which has given a different look and is pretty convincing.

Odd about the haloes. I used to get them with Astronomik but very rarely with Baader. Mine's the 7Nm.

Olly

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Thanks for all the comments. Attached is the color version. I need some advice with the Ha in RGB shots. If I use the Ha subs as the Red channel it makes the Flame nebula look redder than it should be as that nebula has a more orange or yellowish tint in natural RGB colors. What I did here is just stack the Ha and Red subs together for a slightly improved red master frame. The Flame is still a bit red and the dusty details in the Ha are somewhat lost or muted. Should I be using a more sophisticated process like I did for this shot of the SMC?

Stargazers Lounge - alaskacam's Album: Galaxies - Picture

In that one I used pixel math in PixInsight to help Ha pull out the nebulosity in the red channel. It worked well, but I was afraid that it wouldn't with such a Ha dominated area like the Horsehead. Thanks.. Rob

post-16279-133877710258_thumb.jpg

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I never use Ha as luminance beyond an opacity of about 15%, with one recent exception, the Flying bat, I think. It tends to turn things pink and create blue star haloes, though the fine detail makes it really tempting.

My own preference is to apply Ha to red in Blend Mode Lighten. If you have a really strong red signal it may make little difference, in which case I stretch the Ha while it's pasted over the red layer until I see it have some effect. It can be the other way round, though, the Ha overwhelming the red. In this case I will make an initial application of Ha at about 30% opacity and see how it looks. I might then bring more in. Occasioanally I might add a bit in blend mode normal as well but that will be the last resort because it affects star colour.

Between each iteration I'll look at the colour balance and saturation in each channel. If the reds are turning pink a bit more saturation helps. If they are dominating I just lower the curve. I'll have a pure RGB open and try to keep the colours consistent with that in the HaRGB image.

If star colour is affected you can paste the HaRGB onto the RGB and select the stars, feather the selection and erase the HaRGB cores to let the true star colour back through again.

After all that, Harry tells me that PI has an Ha application routine which is good. It's the kind of thing PI does well so I'll be having a look.

Olly

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Hi

If you used my pixel maths to add the ha to the red channel I suggest that you try the following

1) add ha to red with a low multiple factor ( say o,5 )

2) add ha to blue with a low " " ( say 0.1)

3) add ha to Lum "" "" " " ( say 0,2 )

Of course the right balance is a try and see thing :D

Harry

Thanks for all the comments. Attached is the color version. I need some advice with the Ha in RGB shots. If I use the Ha subs as the Red channel it makes the Flame nebula look redder than it should be as that nebula has a more orange or yellowish tint in natural RGB colors. What I did here is just stack the Ha and Red subs together for a slightly improved red master frame. The Flame is still a bit red and the dusty details in the Ha are somewhat lost or muted. Should I be using a more sophisticated process like I did for this shot of the SMC?

Stargazers Lounge - alaskacam's Album: Galaxies - Picture

In that one I used pixel math in PixInsight to help Ha pull out the nebulosity in the red channel. It worked well, but I was afraid that it wouldn't with such a Ha dominated area like the Horsehead. Thanks.. Rob

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