First M27

Bolts_Tweed (Mark) · #1 21-07-2011, 07:57 PM

Thought id have a crack at this and it was a lot harder than I thought - still not happy but this is first process. I am trying to repect the light

but this thing should look like a half a ripe lime with a thin red skin - the OIII and Green channels are just so dominant.

I took Lum 60 min in 10 min subs, Ha 90 min in 15 min subs, OIII 90 min in 15 min subs, RG & B 30 min in 5 min subs bin 2x2. Planewave 17 inch CDK f6.8 and an SBIG STL11k (GRAS 7). There id a little bit of blue inside the inner shell but outside that it is all G & OIII so i didnt push the blue out there.

I'll have to go through kens HDR tutorial as it is a bit cooked in places but this will do for now.

MB

RobF (Rob) · #2 21-07-2011, 09:34 PM

G'day Mark, great to see you posting.
There's some amazing life in that - it's electric like there really has been a big bang. I love the shells of OIII material and the colours of the stars coming through.

Bolts_Tweed (Mark) · #3 21-07-2011, 09:48 PM

Gday Rob - yeah I dont post a lot but in this case Im not really saying I think this image is good - it is really just me trying to work out Kens tutorials (I stick em on my wll in the observatory more than on the web

)

I had another crack at Kens MSLDB technique and I suspect I am wielding it like a sledge hammer more than a scalpel as per his comments in the tutorial but it can really extract some detail.

Anyway Ive been sitting in front of this computer for far too long - I cant even recognise rubbish now. Fresh eyes in another session might pay off over the weekend (going to Leyburn tommorrow). Heres a record for a sidonioing an image (about an hour)

MB

Paul Haese · #4 22-07-2011, 03:37 PM

Actually both of these images are not as bad as you think Mark. I pay little heed about this "respect the light notion" (yes I know who said this and I don't agree with this thinking entirely). Film is different from digitals response, film tended to burn out easily and bright areas blew out quickly and that left the dark areas quite dark most of the time.

Film was quite linear and the notion suggested is reflective of those times (no doubt this will start a debate but there I said it, I worked with film and that was my experience) Digital on the other hand means that all the dynamic range can now be addressed. So utilise the full capacity of your sensor mate. I think that your outer areas could be worked a little more as these look a little black clipped, but there is some very fine gas detail well away from the object.

I would suggest that a hubble image to compare with will give you an idea where to head here. That said, this is a fine result all the same. Just my opinion and each to their own I guess.

DavidTrap (David) · #5 22-07-2011, 04:40 PM

Quote:

Originally Posted by Paul Haese

Actually both of these images are not as bad as you think Mark. I pay little heed about this "respect the light notion" (yes I know who said this and I don't agree with this thinking entirely). Film is different from digitals response, film tended to burn out easily and bright areas blew out quickly and that left the dark areas quite dark most of the time.

Film was quite linear and the notion suggested is reflective of those times (no doubt this will start a debate but there I said it, I worked with film and that was my experience) Digital on the other hand means that all the dynamic range can now be addressed. So utilise the full capacity of your sensor mate. I think that your outer areas could be worked a little more as these look a little black clipped, but there is some very fine gas detail well away from the object.

I would suggest that a hubble image to compare with will give you an idea where to head here. That said, this is a fine result all the same. Just my opinion and each to their own I guess.

As I understood the "respect the light" message said that there are bright parts of an object and dim part. The example used at the conference was m42. If you bring out the detail in the core, but make the periphery of the object the same brightness, you are not truly representing the ranges of brightness of the object.

DT

gregbradley · #6 22-07-2011, 05:03 PM

I like the original Mark. The 2nd seems to have damaged the stars a bit (they look muted).

Its good to see it was done with a CDK17. It makes me realise what my scope could do at my dark site (Rob Miller PME tripod here I come!).

I personally would like a little more brightness to that central X.

Love the colour scheme.

Greg.

Paul Haese · #7 22-07-2011, 05:08 PM

Quote:

Originally Posted by DavidTrap

As I understood the "respect the light" message said that there are bright parts of an object and dim part. The example used at the conference was m42. If you bring out the detail in the core, but make the periphery of the object the same brightness, you are not truly representing the ranges of brightness of the object.

DT

Yes I know the gist of it David, but respectfully disagree. While some parts might well be brighter than others I don't think this difference would be at all noticable from say 40 Au away. All you would likely see is the bright stars and little if any nebulosity due to the radiation being emitted by the stars.

If in the example of M42, you did not use layering to bring out the core and tone done its brightness everyone would have what film used to do. A blown core and outer areas not showing properly and then a histogram which is severely clipped. Digital is an entirely different prospect and should be utilised correctly to show all the dynamic range. I just don't think David has got it right on this occassion. Like I said my opinion and each to their own.

Anyway this is Marks thread and I have said my bit.

jase (Jason) · #8 22-07-2011, 09:52 PM

Excellent Mark. Have to say this isn't the easiest object to process. Its strong in both Ha and OIII making it difficult to get a balance. Matching the two would simply wash out the other. You've done a good job. Would recommend sticking with an Ha:OIII:OIII blend and getting the right detail out of the Ha. OIII is featureless within the center but increases in depth as the shell expands. You've started to capture this effect nicely. Keep working that data over.

strongmanmike (Michael) · #9 23-07-2011, 10:59 AM

Quote:

Originally Posted by Bolts_Tweed

Heres a record for a sidonioing an image (about an hour)

MB

An hour

...looong way to go there boy

(ie you're smart)

Overall this looks pretty good to me, I like the glowing outer envelope, it's a great object for a bit of focal length, nice work

Mike