NGC 7380 Wizard Nebula HaRGB

[x6gas]

Over the past few weeks I've captured quite a lot of data for NGC 7380 - the Wizard Nebula in Cepheus.

This is an HaRGB rendition - actually the first HaRGB I've tried, I think (have done LRGB galaxies before, but otherwise I've done straight narrowband). Anyway, I've followed Olly's advice and added the Ha to the red channel in blend mode lighten. Nice to have some star colour in one of my nebula images, but I kind of miss the definition that the narrowband filters give...

I decided to image this with my Tak as I wanted a wider field to take in the stars, but I've sort of regretted that too and think my EdgeHD would have done quite well on this... ho, hum!

Scope: Tak FSQ85ED

Camera: Atik 490ex

Mount: CGEM DX

Guiding: Atik OAG, IMG0H, PHD

Stacked in AstroArt 5, registered with RegiStar, processed in Photoshop CS5.

Closer crop:

As usual any suggestions very welcome.

Thanks for looking, Ian

[x6gas]

Sorry, forgot to post the data:

Ha - 21 x 1200s

R - 57 x 120s

G - 53 x 150s

B - 60 x 180s

I probably went over the top with the RGB and have ended up with slightly strange numbers of subs as I was using AstroArt to automatically reject anything with a FWHM >2.

Cheers, Ian

[Marvaz]

Great image. I love this object.

[x6gas]

Thanks Marvaz - much appreciated.

[Mark72]

Nicely done Ian, you did a great job of adding Ha.

Mark

[nmoushon]

Thats a good looking image. Where I think you cut yourself short was not with the number of subs for RGB but the lengths. Not saying you needed to do 1200 sec exposures but I would've done at least 300s for each. Why'd you do them so short?

[Martin-Devon]

Ian, you've done well with the HaRGB - it's a good looking Wizard.

Did you blend in all of the Ha into the red, or just a percentage? In terms of colour, I'm leaning slightly more to the lovely narrowband Wizard you posted a week ago - but there again I'm biased towards narrowband colours! Also, I think the detail is a tad sharper in the narrowband version too. But it's nice to have the RGB star colour that's present in this image. It may be possible to add RGB star colour onto the narrowband nebula colour to get the best of both, but I think this is a little tricky to do?

Martin

[x6gas]

Nicely done Ian, you did a great job of adding Ha.

Mark

Thanks Mark.

[x6gas]

Thats a good looking image. Where I think you cut yourself short was not with the number of subs for RGB but the lengths. Not saying you needed to do 1200 sec exposures but I would've done at least 300s for each. Why'd you do them so short?

Ah well that's an interesting point nmoushon! I was getting saturated stars after just 120s on the red channel so decided to stick with that - is that not right? Still learning here!

[x6gas]

Ian, you've done well with the HaRGB - it's a good looking Wizard.

Did you blend in all of the Ha into the red, or just a percentage? In terms of colour, I'm leaning slightly more to the lovely narrowband Wizard you posted a week ago - but there again I'm biased towards narrowband colours! Also, I think the detail is a tad sharper in the narrowband version too. But it's nice to have the RGB star colour that's present in this image. It may be possible to add RGB star colour onto the narrowband nebula colour to get the best of both, but I think this is a little tricky to do?

Martin

Cheers Martin. I took the Ha at 65% on the red with blend mode lighten and levels adjusted to keep the same background. Incidentally, I usually work with a background sky level of about 30 as I like to leave the sky a little grey, but this one I kept around 20 during processing to allow me to blend out halos around the brighter stars in the blue channel (and a little in the green)...

I think I prefer the full on narrowband too - and I am just experimenting with adding in the RGB star colour. It is indeed not as easy as I thought! If anyone has any tips...

[Welrod50]

A great deal of effort has gone into this and it shows. Very nice and thanks for sharing!

[nmoushon]

Ah well that's an interesting point nmoushon! I was getting saturated stars after just 120s on the red channel so decided to stick with that - is that not right? Still learning here!

If they were getting saturated that early then maybe you did the right thing. I'm still using a dslr some with ccd I'm sure its different. Thats just what I thought was the norm. Can you do a seperate star color layer with saturated data by not stretching it as much as you would normal data? I'm trying to learn here too as I'm making my way to ccd hopefully with in the year so sorry if my questions are way off basis.

[x6gas]

A great deal of effort has gone into this and it shows. Very nice and thanks for sharing!

Thanks Scott

[x6gas]

If they were getting saturated that early then maybe you did the right thing. I'm still using a dslr some with ccd I'm sure its different. Thats just what I thought was the norm. Can you do a seperate star color layer with saturated data by not stretching it as much as you would normal data? I'm trying to learn here too as I'm making my way to ccd hopefully with in the year so sorry if my questions are way off basis.

Well I appreciate the comment and would be really interested to hear views on this. I was thinking that maybe my RGB subs were too long!

Here's a combined RGB image with no stretching or scaling at all - just lobbed in to PS and colour mapped... and then saved at 800 px wide.

[ollypenrice]

It's very attractive. I know that you can't have NB sharpness, contrast or star size in broadband natural colour but natural colour is... natural colour! For me it always has a different richness and depth.

I think what you can do, though, is over-process the Ha, making it too sharp and too contrasty, prior to addition to the red in BM Lighten. The over processing will then become heavily diluted. I'm not averse to adding a whiff as Luminance, either. Rarely more than 15%, though.

I no longer agonize about how much Ha to add to red. I bung it all in and then paste the result over the pre-Ha image and choose an opacity which looks best.

I do think your colour subs are too short. The nebula does have other colours but they won't get a look in against that level of Ha dominance. Saturated stellar cores are not the end of the world. You can pull them down later and blur in the colour from the outer parts of the star.

Olly

[x6gas]

It's very attractive. I know that you can't have NB sharpness, contrast or star size in broadband natural colour but natural colour is... natural colour! For me it always has a different richness and depth.

I think what you can do, though, is over-process the Ha, making it too sharp and too contrasty, prior to addition to the red in BM Lighten. The over processing will then become heavily diluted. I'm not averse to adding a whiff as Luminance, either. Rarely more than 15%, though.

I no longer agonize about how much Ha to add to red. I bung it all in and then paste the result over the pre-Ha image and choose an opacity which looks best.

I do think your colour subs are too short. The nebula does have other colours but they won't get a look in against that level of Ha dominance. Saturated stellar cores are not the end of the world. You can pull them down later and blur in the colour from the outer parts of the star.

Olly

Thanks Olly - I was hoping that you'd chime in as the Master of HaRGB!

So are you saying I should overprocess the Ha and that it will calm down anyway as I blend it in to the red? That would make sense especially since I seem to lose contrast during processing...

And longer RGB subs it is then! Any hints on how much longer? Double? Triple? I was quite pleased with the results I had with LRGB galaxies earlier in the year; that was with similar length subs but binned 3x3 albeit on a slower scope. Taking into account the Tak is a full stop faster than my reduced EdgeHD maybe I should be going 3-4 times longer than this on the Tak...

[nmoushon]

Olly's suggestion of adding some L would be interesting to see. I think it might give you some of that detail you are more accustom to in narrowband.

As to sub length I would suggest at least 5min sub maybe even 10min to help balance and bring out the other colors there. As Olly said you'll need it since you have such a power house of Ha. Plus you can never have enough subs

[andyo]

Great job done for a HaRGB nice detail and he colour is good.I just tried my first HaRGB using this method(method 2) http://starizona.com/acb/ccd/software/ps_hargb.aspx I still found the colour was washed out and still needed a fair bit of processing to recover it.If you could point me in the direction of the method you used that would be appreciated

[x6gas]

Olly's suggestion of adding some L would be interesting to see. I think it might give you some of that detail you are more accustom to in narrowband.

As to sub length I would suggest at least 5min sub maybe even 10min to help balance and bring out the other colors there. As Olly said you'll need it since you have such a power house of Ha. Plus you can never have enough subs

Yes, thanks, I'll try adding in a little Ha as a luminance level and see where that takes me...

I've also been tickering with a more agressive stretch of the RGB data (but over did it and it ended up drowning out the nebula... so something in between, maybe!)

[x6gas]

Great job done for a HaRGB nice detail and he colour is good.I just tried my first HaRGB using this method(method 2) http://starizona.com...e/ps_hargb.aspx I still found the colour was washed out and still needed a fair bit of processing to recover it.If you could point me in the direction of the method you used that would be appreciated

Thanks Andy and thanks for the link; those methods look interesting.

So I'm starting with stacked and registered TIF files for each of the channels (Ha / R / G / B ) and I bring them in to Photoshop completely unstretched. I then colour map the image for each individual filter and combine them in the normal way (more or less as described here, except I now use the clipping mask technique - sorry I am sure there are better tutorials on the web, but I can't immediately find them!)

I then pasted the processed Ha image as a new layer on top of the image being used for the red channel, set the blend mode to 'lighten' and reduced the opacity to 65%.

I did increase the saturation a bit to boost the star colour, and also upped the reds a little bit using a selective colour adjustment (a tip from Olly on another thread was to add a selective colour layer adjustment and for the reds, move the cyan slider a bit to the left).

HTH, Ian

[andyo]

Thanks a lot Ian much appreciated, will try some reprocessing on mine using the method you have outlined

[Gina]

That's really lovely

[x6gas]

That's really lovely

Thanks Gina.

[x6gas]

I've taken Olly's advice - well some of it - and boosted the Ha with a curves adjustment and then selectively applied an 8 pixel High Pass filter to it before blending it in to the red channel in blend mode lighten.

I think it's an improvement. I'm not completely happy with the hue of the red, but playing around it's either too magenta or too orange so this is a bit of a compromise... Like the star colour, though. If only I could figure out how to blend the RGB stars in to the Hubble version without it looking awful!

Thanks for looking and Clear Skies,

Ian

[nmoushon]

Thats really RED! But I kind of like it actually! Really brings out the dark regions and makes them pop. I like the contrast even if its different.