Gum 56 in Scorpius - 2 Frame Mosaic

Martin Pugh · #1 19-09-2008, 12:26 AM

Hi all
I started collecting data for this in mid-June and got the last few 2
nights ago.

This is a 2 frame mosaic of this lovely nebula in Scorpius. I did a
widefield version of this last year, but this is the high-res companion
consisting of 46 hours total exposure time (6hrs SII, 6hrs OIII, and 11
hours HA per frame).

Of course, stellar FWHM is always reduced with narrowband, but with the
AO-L working as well, many of these frames came in at 1.3-1.6" raw FWHM.

Usual kit - 12.5" RC, STL11K, AO-L, Astrodon filters, PME.

Cheers and thanks for looking

Martin
http://www.martinpughastrophotography.id.a u/IC4628Mosaic.jpg

AlexN · #2 19-09-2008, 12:34 AM

Stunningly vibrant colors..
The detail and clarity of all the different structures is amazing, and gawd look at all those tiny little pin point stars!!!

Fantastic image Martin...

Kirkus (Kirk) · #3 19-09-2008, 04:32 AM

Wow, Martin! Just wow!

iceman (Mike) · #4 19-09-2008, 04:53 AM

Wow indeed. That's very special!

RB (Andrew) · #5 19-09-2008, 05:57 AM

Stunning image Martin !

I noticed a few of red stars/dots, is that actual star colours or artifacts from the SOH process?

gregbradley · #6 19-09-2008, 06:02 AM

That is fantastic Martin. 46 hours, what a feat!

Greg.

gregbradley · #7 19-09-2008, 06:04 AM

Hi Andrew,

Whats a SOH process?

Greg.

h0ughy (David) · #8 19-09-2008, 07:17 AM

WOW there is some fantastic detail in that shot.

RB (Andrew) · #9 19-09-2008, 07:28 AM

Quote:

Originally Posted by gregbradley

Hi Andrew,

Whats a SOH process?

Greg.

The SII, OIII, and HA process.
Just wondering, because I don't have any experience with it, I've only done DSLR imaging.

Just wondering if it's artifacts or normal with this type of processing.

Garyh · #10 19-09-2008, 07:53 AM

Excellent work like always Martin! Such tiny stars! you certainly do a fine job of the SOH. All blends in beautifully.

I can see superman flying there!

multiweb (Marc) · #11 19-09-2008, 08:27 AM

That's awesome Martin! I really like the central part were the dark nebulosity edge is and you can see the lighter background blending into the pinkish then blue sky. It has a real depth to it. The only thing I don't like about narrow band pictures in general is that the stars almost always have darker halos around the brighter core. It's ok when the stars are on a darker background but they stick out when showing on top of a lighter background. It looks like they're pasted on top of another layer. Is this caused by stacking the different channels? Having said that I have never tried NB and I assume it must be very trying to get the data in the first place and process it. Never the less it's such a great picture. Well done.

bluescope · #12 19-09-2008, 04:24 PM

Awesome image Martin !

mick pinner · #13 19-09-2008, 04:44 PM

obviously a labour of love and a work of art.

Matty P (Matt) · #14 19-09-2008, 05:35 PM

Incredible image Martin!

WOW!!!

RayOfLight · #15 19-09-2008, 05:51 PM

very lovely!

Martin Pugh · #16 19-09-2008, 06:06 PM

Hi all

and many thanks for the generous feedback.

the small red dots are indeed stars (not faults in noise rejection/hot pixels not removed in the SII frames) and they are most certainly a result of the pallette used. Many people shoot RGB to layer on top, but I have refined a technique which almost completely removes the magenta stars/halos common with NB imaging. I will demonstrating this at Lostock.

....and yes, you are absolutely right about the star halos..I am aware of this and thought I had taken care of it....clearly not...so I will be fixing that tonight and replacing the image on my website. Thanks for pointing it out...you are also right about the difficulty associated with NB imaging....its not straightforward considering that some objects are barely visible at these wavelengths....the Helix Nebula at SII is typical of this....I have currently got 16 hours SII on this object and its still not enough.

Cheers
Martin

gregbradley · #17 19-09-2008, 06:16 PM

Martin,

I reckon healing tool the red stars out. Some like to have an accurate representation of the object imaged but I personally favour the product of an attractive and pleasing image. So I have no qualms about deleting offending stars if needed (often not required but you get the occassional quirk). Then again those stars would not be that colour either so it isn't an accurate representation.

Bicolour seems to keep the star colours reasonably well which is a surprise.

Fabulous image. I admire your hard work and your seamless mosaic. Also you have your setup humming which is 90% of the difficulty in this activity.

Greg.

Jeffkop (Jeff) · #18 19-09-2008, 08:14 PM

That is without any doubt the most appealing image I have ever seen. The colours the focus the composition .. I gotta go back n have another look.

Yep ... I was right . THAT IS SOMETHING ELSE

Martin Pugh · #19 19-09-2008, 08:24 PM

Hi Greg

yes, your right...lets not forget that this is false colour imaging...designed to bring out the different energy levels and emission lines in the nebula, altering the pallette as the imager sees fit...its all about aesthetically pleasing images and there is no right or wrong way.

I use a number of methods to keep star colours natural...sometimes I just use remove the magenta and other times I might shoot RGB, or use-bicolour...the latter is the best way as you have already got the data.

I am surprised my system is working at all...I have completely removed the Proline and FSQ again, totally rebalanced, short TPOINT mapping run, cable management, re-initalising...and on and on.

cheers
Martin

strongmanmike (Michael) · #20 19-09-2008, 09:29 PM

...ah you and your CCD autopilot automated RCOS, SBIG, PME, AOL, TPOINT, THESKY etc..heck it's the complete beez kneez....and it still isn't working smoothly?

Well it seems that between the rebuilds, rebalances and false alarm cloud sensor wakeups, you can gather absolute mega data non the less

Not the most interesting area of sky really but your mammoth amount of data has made it quite beautiful - very nice work!

Mike
Greg's new rig is pretty cool too though, just not as automated as yours...yet