vdB 152 and LDN 1217. 23 hrs of LRGB_Ha

[Xiga]

Hi all

After giving up on the hobby for over a year (due to persistent mount issues, which now seems to have magically resolved itself somehow - let's hope it stays that way!) i've finally managed to get enough data for an image. My last one was back in Nov 2022 🙄

I started collecting data for this back in Feb, but then in early April the camera developed a fault and needed to be sent off for repair to fix a faulty usb board. Thankfully, the repair went well, and i got the camera back just in time to get the Red and Blue data to finish this off before we lost astro dark here in N.Ireland. 

Stacked in APP, and gradients removed using GraXpert (which i am very impressed with!). I stretched the Lum manually using GHS in Siril, and the RGB was stretched using arcsinh (in Photoshop) to preserve the colour. All further processing then done in PS. S-XT and N-XT used along the way too, of course. 

Capture details:

Qhy268m, Skywatcher 80ED, HEQ5-Pro

Lum (10 hrs); R (2.4 hrs); G (2.8 hrs); B (3 hrs); Ha (5 hrs). Total (23.2 hrs). 

It's nice to finally be imaging again 😀 Even if i do have to wait to August now for astro dark to return! 

C&C welcome. 

Ciaran. 

Edited May 17 by Xiga

[Kyuss]

Love the framing of the picture! I swear that  there are two birds on the top centre of your image ! i can see their beaks!

Edited May 17 by Kyuss

[Xiga]

1 hour ago, Kyuss said:

Love the framing of the picture! I swear that  there are two birds on the top centre of your image ! i can see their beaks!

Thanks!

Not sure I can see the birds, although I'm usually terrible at seeing shapes in images. 😁

[ollypenrice]

Outstanding, Ciaran. Absolutely everything is great in this image; emission, dust, stars, background (where there is any!)

Olly

[assouptro]

Outstanding image! 
you must be very happy with this one given all the problems you’ve had to overcome! 
 

Thank you for sharing 

Bryan 😊

[Xiga]

16 hours ago, ollypenrice said:

Outstanding, Ciaran. Absolutely everything is great in this image; emission, dust, stars, background (where there is any!)

Olly

Thanks Olly ☺️

I had a hard time processing this. I spent 4 nights on it, and had to start over a couple of times. This was my first time incorporating Ha into a broadband nebula image. I initially spent a fair amount of time looking up how to do it via continuum subtraction using pixel math in Siril. It worked, but then I tried just adding it in PS instead and found I could do exactly the same, only with so much more control, so I went with that. It was also my first time using Generalized Hyperbolic Stretch. I'm very impressed with it. I knew it would tame the stars well, but I was worried I would lose some of the dust along the way, but it seemed to work well. 

[Xiga]

7 hours ago, assouptro said:

Outstanding image! 
you must be very happy with this one given all the problems you’ve had to overcome! 
 

Thank you for sharing 

Bryan 😊

Thank you Bryan! 

Yeah I'm pleased with how it came out in the end. This is easily the most data I've ever captured on a single image, and I really noticed it during processing. 

It's been a frustrating 18 months for sure, and I won't bore you with the details, lol. I'm just happy to be back in the game again 😃

[ollypenrice]

6 hours ago, Xiga said:

Thanks Olly ☺️

I had a hard time processing this. I spent 4 nights on it, and had to start over a couple of times. This was my first time incorporating Ha into a broadband nebula image. I initially spent a fair amount of time looking up how to do it via continuum subtraction using pixel math in Siril. It worked, but then I tried just adding it in PS instead and found I could do exactly the same, only with so much more control, so I went with that. It was also my first time using Generalized Hyperbolic Stretch. I'm very impressed with it. I knew it would tame the stars well, but I was worried I would lose some of the dust along the way, but it seemed to work well. 

I continue to think that Photoshop is usually easier to control than anything else. I add Ha to red using blend mode lighten, though you can also use blend mode screen if you bring in the black point, I've read. I need to try this.

I no longer give any thought to the stars in stretching because I'm going to remove them anyway and replace them with stars of an entirely different stretch. I also remove NB stars now, when adding Ha or OIII to the colour channels. That way they have no effect at all on the RGB stars.

Olly

[gorann]

54 minutes ago, ollypenrice said:

I continue to think that Photoshop is usually easier to control than anything else. I add Ha to red using blend mode lighten, though you can also use blend mode screen if you bring in the black point, I've read. I need to try this.

I no longer give any thought to the stars in stretching because I'm going to remove them anyway and replace them with stars of an entirely different stretch. I also remove NB stars now, when adding Ha or OIII to the colour channels. That way they have no effect at all on the RGB stars.

Olly

Yes, an outstanding image in every way with all those Ha structures nicely brought out!

By the way I learnt yet another way of adding Ha (a Youtube video but forgot which one). First I process the Ha image until I am pleased with it. Then (in RGB mode in PS) I move the slider in Color Balance so that the Ha image becomes purely red. Then I add it to the processed RGB image as a layer in blend mode lighten and can play with curves and transparency (and the brush tool) until I like what I see. So far I have only tried it on galaxies so I am not sure how well it works on an image like this.

Göran

[ollypenrice]

25 minutes ago, gorann said:

 

First I process the Ha image until I am pleased with it. Then (in RGB mode in PS) I move the slider in

I would add one caveat to this. Knowing that my Ha image is destined to lighten the red channel, I don't process it as I would a standalone Ha. I go for more striking contrasts because this will be toned down in the blend, and I don't worry about noise in the background because it will be darker than the same regions in red so it won't be applied. Also I will often give a further stretch once the Ha is in place as a layer over red and I can see what it is or isn't doing.  The beauty of Photoshop lies in its showing the consequences of what you are adjusting as you adjust it.

Olly

[Xiga]

The method I used is a little different.

I first processed the Ha by removing the stars and applying a bit more N-XT than usual. I tried sharpening it, but it was already quite faint and couldn't really take any. Then I added it as a new layer and double-clicked on the layer to open the Layer Style menu. From here, I changed the blend mode to Screen and de-selected the G and B channels. Then I used levels and Curves to really darken the Ha layer a lot, so that it wasn't affecting the sky background. Once I was happy with it, I changed the opacity of the layer to 80% and then made a copy of the layer, only this time I de-selected the R and G channels and changed the opacity to 20%. This way, I was able to weight the Ha 80% to Red and 20% to Blue, which seems to be the consensus for how the Pixel Math brigade do these things. 

Nevertheless, I always trust my eyes over anything else, and I admit I did like the effect. It made the Ha less of a fire-engine red, and gave it a slightly magenta hue, which I really liked, so I think I'll do it this way from now on 😃

[ollypenrice]

40 minutes ago, Xiga said:

The method I used is a little different.

I first processed the Ha by removing the stars and applying a bit more N-XT than usual. I tried sharpening it, but it was already quite faint and couldn't really take any. Then I added it as a new layer and double-clicked on the layer to open the Layer Style menu. From here, I changed the blend mode to Screen and de-selected the G and B channels. Then I used levels and Curves to really darken the Ha layer a lot, so that it wasn't affecting the sky background. Once I was happy with it, I changed the opacity of the layer to 80% and then made a copy of the layer, only this time I de-selected the R and G channels and changed the opacity to 20%. This way, I was able to weight the Ha 80% to Red and 20% to Blue, which seems to be the consensus for how the Pixel Math brigade do these things. 

Nevertheless, I always trust my eyes over anything else, and I admit I did like the effect. It made the Ha less of a fire-engine red, and gave it a slightly magenta hue, which I really liked, so I think I'll do it this way from now on 😃

That's interesting. The argument for adding Ha to blue arises from the fact that the fainter H-beta line, which is blue, traces the same gasses as Ha. I used to do this in the early days but seem to have got out of the habit. I'll take another look.

Olly