Well this has been getting a pretty good hammering recently so I thought I'd throw mine out there too!
Recently bought a QHY183M to get back into narrowband imaging and I've long wanted to photograph this nebula so I figured it would be a good opportunity as it hits meridian around the middle of the night.
I've tried this in the past but when I was using my refractor the camera would hit the tripod for few hours on either side of meridian so I've always avoided it
It also seemed like a good chance to test out the DDM60 with longer unguided exposures so I've set out at 900s at 0.825"/pixel and not been disappointed. I don't have enough back focus with the RH200 to easily add in an OAG or anything.
My biggest trouble processing wise has been trying to decide on a colour balance. The First Version is technically accurate but it isn't one that I find quite as pleasing.
The Second Version I may have gone a little over board with the sharpening but I do find the colour balance a little nicer visually.
The nebulosity is a straight HOO but I've added in nicer stars which have a 50% contribution of Ha and OIII in the green channel.
Nice one Colin, looks nice and sharp which is pretty amazing for 900s unguided at your scale... DDM60 is certainly not disappointing there!
I like the red one on Astrobin too.
Thanks Lee Prior to this the most I'd tested had been 300s at 0.4"/pixel and been happy with that so I figured I'd give it a go. It gets a little sketchy with tracking accuracy past meridian so it's fine as long as it doesn't go past it.
I've also attached the red version which colour wise is my favourite but there really isn't much in the way of OIII contribution which is a LOT stronger behind the dusty regions.
Thanks Greg, I was a little worried at first given that the stars aren't as small as I was hoping for (I shouldn't have been surprised really). At 900s the star burst is HUGE but it calibrates out very well. This was taken at the lowest gain (highest dynamic range) but even then it's only got 2e- read noise!
- You've captured the OIII shock fronts around the central super-luminous cluster beautifully.
- The dust details are exceptional.
- Artistically, it looks like we are seeing an enormous cavern, lit from within, sculpted out of very dark rock.
One of, if not your best, image Col ...you have finally mastered stars processing Incredible detail in both images but on close (full size) inspection No2 breaks down pretty badly, so I give it to No1 Excellent resolution of structures (as opposed to artefact driven pseudo detail) but without significant artefacts, wins over colour palette any day in my book, top result
I and Marcus Davies are wrapped with my average guide errors of +/- 0.2 arc sec with autoguiding ...but 900 sec unguided with such resulting sharpness, is, well, truly unbelievable mate, super duper...great stuff
Super sharp. 900s unguided. Far out. What a tease... I can't do 1min.
Your stars always look great out of your M210 so whatever you're doing it's working well anyway
Quote:
Originally Posted by Placidus
An amazing rendition.
Three super-good things:
- You've captured the OIII shock fronts around the central super-luminous cluster beautifully.
- The dust details are exceptional.
- Artistically, it looks like we are seeing an enormous cavern, lit from within, sculpted out of very dark rock.
The 900 seconds unguided is quite an achievement.
Bravo!
Thanks M&T, it's still nothing like your 1 hour subs! That is an achievement unto its own
It really is one of those regions that just pops out in narrowband. Some HOO or SHO regions can look like bland but most renditions of this area do have a great look and feel to them.
Quote:
Originally Posted by marc4darkskies
Wow! 900sec unguided! Very impressive and so is the result! A very pleasing and tidy image Colin.
Thanks Marcus, I could probably push it further than 900s but I've reached the point where my background regions are 10x read noise in OIII and about 8x in Ha.
Quote:
Originally Posted by strongmanmike
One of, if not your best, image Col ...you have finally mastered stars processing Incredible detail in both images but on close (full size) inspection No2 breaks down pretty badly, so I give it to No1 Excellent resolution of structures (as opposed to artefact driven pseudo detail) but without significant artefacts, wins over colour palette any day in my book, top result
I and Marcus Davies are wrapped with my average guide errors of +/- 0.2 arc sec with autoguiding ...but 900 sec unguided with such resulting sharpness, is, well, truly unbelievable mate, super duper...great stuff
Mike
Thanks Mike, I do completely agree with you Re #2. Processing was moving from PI into Lightroom where I did a colour balance change and moved some sliders. Then saved it and sent it to my iPhone where I used Lightroom on there to then move some sliders around again
FYI, I've done some pretty extreme deconvolution
The mount really does all the work, it is a bit fiddly to setup and it would be SO much nicer with a permanent one but that's for a future endeavour.
IMO - I prefer the red one aesthetically, the big stars have not been blown out as much as they have on the other ones.
The over sharpening is interesting and dramatic, but to paraphrase Strongman Mike - "Gaseous structures, probably should'nt have too hard an edge". So is the Ara wall gas, dust or both? Hmmmm
If anyone knows the answer, it's probably you though!
(Sigh) I dream of round stars like yours - still havn't sorted out my issues....
IMO - I prefer the red one aesthetically, the big stars have not been blown out as much as they have on the other ones.
The over sharpening is interesting and dramatic, but to paraphrase Strongman Mike - "Gaseous structures, probably should'nt have too hard an edge". So is the Ara wall gas, dust or both? Hmmmm
If anyone knows the answer, it's probably you though!
(Sigh) I dream of round stars like yours - still havn't sorted out my issues....
Thanks Andy, I definitely prefer the red one visually as well but from a technical standpoint, the colour is wrong
It was a 5-10 minute process end to end. Most of the detail in that version comes from removing the L component from the other version and then putting it into the red one.
It is right that there are no hard edges with dust and space... but... it’s all a matter of distance. Take Bok globules, they often appear to have a sharp edge between the dark dusty globule and their background but it really is a gradual transition but that isn’t visible at 8,000 light years away.
The same also happens with gas and this can be seen in the Pillars of Creation from Hubble. Some parts have hard high contrast edges while others are gradual and more diffuse.
The detail in this image is astounding, I like the first image batter as well
I aim to tackle this with my larger refractor when the guide camera arrives. Awesome work Colin
Prior to this the most I'd tested had been 300s at 0.4"/pixel and been happy with that so I figured I'd give it a go. It gets a little sketchy with tracking accuracy past meridian so it's fine as long as it doesn't go past it.
Super sharp. 
900s unguided. Far out. What a tease... I can't do 1min. 
Incredible detail in both images but on close (full size) inspection No2 breaks down pretty badly, so I give it to No1 
Excellent resolution of structures (as opposed to artefact driven pseudo detail) but without significant artefacts, wins over colour palette any day in my book, top result 
are wrapped with my average guide errors of +/- 0.2 arc sec with autoguiding 
