Rosette Nebula HOO ;-)

[decay]

Hi all,

with regard to the latest duoband / bicolour / HOO discussions here with Nick, Mike, Martin & Justin ( ), I would like to add my two cents

rosette-2_03.jpg (683.93 KiB) Viewed 3241 times

- 200/1000 GSO Newton / SkyWatcher EQ-5
- Baader MPCC
- L-eNhance
- EOS 2000Da, APT
- 50/200 Guide Scope, ASI 120 MC, PHD2

- 12 x 300s @ ISO 1600 (~ 1 hour)
- flats, darks, bias

This is from one of two or three 'clear' nights we had here since maybe three months. 'Clear' means, that there have been a few usable hours until high fog slowly set in. I was pretty exited, because this was the first time I managed to collect about 3.5 hours of light. But unfortunately I had to sort out about 2/3 of the subs because of the fog. So again, only about 1 hour of light for me

As described in Justin's thread, the processing with StarTools was pretty straightforward. I tamed Ha in order to bring out OIII a little more. Worth mentioning is only the second run of the Color module in order to desaturate the halos of the stars. For me the look of the stars is - well - quite OK. Yes, some people do layer in RGB stars, but for me this often looks kind of 'unnatural'. But the most important reason for me not to do that (until now) is that observation time here is rather rare and I prefer to use it for other objects instead for imaging RGB stars.

Best regards, Dietmar.

[firebrand18]

Very nice Dietmar! The Rosette does provide a better OIII amount than some other emission targets and you captured it well here.

Did you run the 2nd Color iteration right after the first or wait until tracking was off after denoise? Did a good job on the blue halos; will try that.

I agree with the RGB layering dilemma; kinda nice but perhaps not worth the effort wasting a clear night to shoot stars!

CS
Nick

[Mike in Rancho]

Rather amazing for just an hour!

And quite crisp in there around that central star cluster.

[decay]

Did you run the 2nd Color iteration right after the first or wait until tracking was off after denoise?

I ran the Color module for the second time right after using the Shrink module, Nick. So this workflow

Color -> Shrink -> Color (desaturating stars with mask)

You could try reducing or increasing the size of the star mask. And maybe do a separate run with 'fat stars' only. (But I didn't do that in this case.)

Best regards, Dietmar.

[decay]

And quite crisp in there around that central star cluster.

Thanks, Mike Yes, I also noticed, that sharpness decreases towards to the outer regions. This is usually not the case for me, so I don't think this is due do optical problems. But what could it be then?

Best regards, Dietmar.

Edit - P.S.: I would like to mention that SVDecon did a great job again, especially in the inner regions. If I remember correctly, it was ST 8.

[firebrand18]

Thanks for the flow Dietmar. A big fan of the evolving SVD module and process all my images with sampling; rare to go back to synthetic decon.

I'm curious of everyone's thoughts on the Spatial Error "e" option within SVD. Not sure what this entails but I get better results on stars using it.

Nick

[Mike in Rancho]

Thanks, Mike Yes, I also noticed, that sharpness decreases towards to the outer regions. This is usually not the case for me, so I don't think this is due do optical problems. But what could it be then?

Best regards, Dietmar.

Edit - P.S.: I would like to mention that SVDecon did a great job again, especially in the inner regions. If I remember correctly, it was ST 8.

I noticed that too, Dietmar.

Focus, or coma corrector?

I'm also wondering if I see it more in the larger saturated stars rather than the small ones. And on those, something may have happened in the processing? The star cores themselves seem to have turned into bright but rather flat white disks, but they have a sharp edge and possibly a thin line of different color surrounding that edge. That may be giving an appearance of having more clarity, but now on further thought I'm not sure that's truly the case.