NGC 6744 Pavo Galaxy

[Startrek]

Clear nights during the New Moon period this year have been few and far between. Last week presented two clear nights with a slithered waxing moon descending in the west so decided to image NGC 6744 a spiral galaxy in the constellation of Pavo ( Peacock ).Its quite a spectacular galaxy dominated by a bright dense star field. At magnitude 9.1 and apparent size of 20.0' x 12.9' ,its well within the capabilities of my 10" f5 Carbon Newt ( focal length 1250mm )
Conditions were below average which reflected in average guiding and resultant slightly bloated star sizes.

15% to 20% waxing Moon
Seeing below average
Bortle Class 3
NexDome Obs
10" f5 Klaus Helmerich Carbon Fibre Newt
Skywatcher EQ8 - R Pro Mount
PHD2 Multistar Guiding ( 0.65 to 0.75 arc sec )
Imaging Camera ZWO2600MM , Gain 0, cooled to -10C
Luminance subs 65 x 3 min
Red subs 32 x 3 min
Green subs 31 x 3 min
Blue subs 32 x 3 min
All subs dithered
Total integration 8 hours
Flats LRGB
Darks from Library
Flat Darks LRGB
Data analysed,calibrated, aligned and stacked in ASTAP
Post processed in Startools V1.8 ( via Compose L + Synthetic L from RGB, RGB )

Obviously a mag 9.1 galaxy generally requires significantly more data but quite pleased with what detail I could extract with only 8 hours.

Link to Astrobin for full resolution……,
https://www.astrobin.com/ssx39l/

Attached versions IIS 200Kb

Thanks for Looking
Comments welcome

Clear Skies
Martin

[strongmanmike]

Looks good Martone, with some good resolution, maybe a bit on the dark side?..perhaps brighten it up a bit might look good?

Lucky we only have one Moon huh? :eyepop: imagine what astronomers on Jupiter would have to put up with! :P

Mike

[Ant0nio]

Looking good Martin, I'm sure you're poised for the next opportunity to gather more data on this one as you have a solid foundation there already. Looking forward to the next update. :)

Cheers,
Tony

[gregbradley]

Looks good Martin. It's a dim galaxy.

Worthy of more exposure time.

Greg.

[alpal]

It's a nice pic Martin,
I would have processed it differently -
much brighter as it's mostly using only half the available dynamic range
and it could do with a colour boost in saturation -
and also contrast enhancement on the central part
of the galaxy with a blurred layer mask.
Some of the brighter stars have a mixture of red, green and blue halos.
I'm not sure what has caused that and if it could be fixed?
Was it an alignment problem in stacking?

cheers
Allan

[TrevorW]

I would expect a more dynamic image from the quality of your skies and the amount of data although more would help, the details there just needs more IMO :)

[PRejto]

I appreciate the understated processing! The galaxy is dim and this image conveys that. It also has a dimentional effect of putting the stars in the foreground and the galaxy behind which is realistic in my view given how many photos look "flat" with the stars and galaxy seemingly at the same distance. Photos that look like christmas lights are not my cup of tea. I do agree that the stars while appearing sharp and focused do have that odd fringing. As Allan remarked perhaps there is an alignment issue? Anyway, well done. This is a tough subject!

Peter

[Startrek]

Gee I wasn’t expecting an APOD with only 7.5 hrs of data on a dim galaxy.
If I captured 15 to 20 hours plus then things would be entirely different.
Ok all points of critique understood and accepted.
I’m going to revisit the processing and boost the brightness at the expense of loosing some fine detail , plus boost saturation to bring out more colour.
As far as the stars are concerned, I didn’t use the fringe killer tool , highlight repair or colour taming tool in ST to correct the colour aberration, my fault !!
Admittedly I held back on the auto stretch to mitigate some fine noise ( I did have some moon glare on 30% of my data over both nights )
5 min subs in lieu of 3 min would have improved detail. I did try stacking in both DSS and ASTAP and ASTAP was the clear winner with a clean lower noise image.
At the end of the day more good data would improve the image quality , no doubt about that.
As I normally image in B8 skies in Sydney , imaging under B3 at my Dome on the South Coast on a broadband target is an ongoing WIP and experimentation.
My imaging time over a calendar year is usually 70/30 ( Sydney / South Coast )
Broadband imaging in Sydney is virtually impossible due to the amount LP under B8 and the availability of clear sky time during new moon periods.

Thanks all for your input
Cheers
Martin

[Stephane]

Nice work Martin on a dim galaxy! It’s great being able to appreciate the fine details on the Astrobin link. I’m hoping to image this galaxy too in the near future and will travel to darker skies for the first time.

[Startrek]

Thanks Stephane,
Even under B3 skies it’s a dim rascal
Like most dim objects collect loads of data but not always available due to Mother Nature
Cheers
Martin