M83 Southern Pinwheel Galaxy with 6” Newt

[Startrek]

Managed 2 reasonably clear stable nights in Sydney last week with intermittent passing high cloud and a 50% waxing moon.
Captured M83 Southern Pinwheel Galaxy with my trusty little 6” Newt and ZWO2600MC
250 x 60 sec subs over 2 nights ( discarded 12 bad subs )
2 x 40 Flats
60 x Bias
Another 250 subs would have been nice to improve SNR but life gets too busy even in retirement and had to be up early both days. Cloudy weather followed……
Processed the noisy data as best I could and ended up at least an image.
It’s a real struggle imaging Broadband targets especially galaxies under Bortle 7/8 skies with a relatively small aperture and focal length and a OSC camera but it does provide a challenge which is good. The 50% waxing moon didn’t help either.

Astrobin link below …….
https://www.astrobin.com/ctdw2n/

Stacked in DSS ( multiple nights stacking )
Processed in Startools v1.8 ( Linear OSC Bayered and not white balanced)

Original frame version
Crop version

Comments welcome
Thanks

[AstroViking]

Hi Martin,

Another great image from you. That "little" scope does a fantastic job of catching photons, and you've got some great colour in there.

I notice you've got "double" diffraction spikes on the bright stars - are they accidental or on purpose?

Cheers,
V

[Dave882]

Amazing detail Martin. Great processing to really get the most from that data! Great work mate!!

[Startrek]

Thanks Steve,
Most folk wouldn’t bother imaging galaxies with small scopes and heavy LP ( Bortle 8 ) plus the fact of a small window each month when Mr Moon is gone or small. It’s a difficult task to mitigate noise and extract true signal whilst trying to find the best image size and Bin value to maximise SNR. I had about 4 attempts to process this one. Even with vasts amount of data , poor quality data won’t help with resolution and detail. These galaxies are such dim buggers and don’t give you much headroom
About the diffraction spikes on the two or three larger Stars , I can’t really see doubles on my screen , although you might have a much higher res computer screen ? It’s certainly not my intention but you have to remember my scope is worth $200 ( it’s definitely not an $8K Mewlon !! ) If they’re there well I can’t see em , I’m more concerned about residual noise and resolution in the main galaxy structure
Cheers
Martin

[Startrek]

Thanks Dave,
It’s a battle but worth the effort
You gotta give everything a whirl , even with a small rig

Cheers
Martin

[pkinchington]

looks really good!:thumbsup:
Cheers Kanga

[AstroViking]

Hi Martin,


The extra spikes are between the vertical / horizontal "big spikes". If you were using a camera lens I would say they are caused by the aperture blades, but with a Newt, I'm puzzled as to how they would be created.



Cheers,
V

[Startrek]

Steve,
These aren’t diffraction spikes
It’s the stars natural glare or aurora which has been tightened due to Deconvolution
I throttled the Decon a tad too heavy trying to tease out more detail in the Galaxy core and spirals
The Apodization mask didn’t quite cover this area so hence this “soft spiked look”
I don’t mind this look

Again 8 to 10 hours of good data ( instead of only 4 hours ) would have made a huge difference to the overall image.

Sydney , the most light polluted City in Australia is tough on broadband imaging , especially Galaxies, with relatively small rigs

Hope that explains it

Cheers
Martin

PS: At native scale view you can’t really notice it unless you stare at it or pixel peep

[Startrek]

Thanks Kanga !
Not the most ideal equipment and Sky to shoot galaxies but worth the effort all the same

Cheers
Martin

[AstroViking]

Thanks for the explanation, Martin. Makes sense now.

And yeah, I like the look of them, too.

[Craig_]

Turned out great given the challenges involved in capture!

[Startrek]

Thanks Craig

[strongmanmike]

It's pretty cool that one can image a galaxy at all from the middle of LP-ville :eyepop: :cheers:

Mike

[Startrek]

Thanks Mike !!
Yep agree, it’s not until you drive into outer Sydney at night from a high location where you get a view of the whole Sydney basin lit up with light glow and say to yourself “I actually image through all that gunk”
Broadband is a battle but doable, if you’re willing to put the hours in and Mr Moon is not around.
Pretty happy with that image from a relatively small Galaxy rig.
Cheers
Martino
aka Startrek ( Andy Warhol )

[Garyh]

4 hours under bortle 8 skies! Now that's a battle but you ended up with a nice m83!
Definitely worth the effort.. I only have short focal length scopes but that doesn't stop me getting these little galaxies!
Good job!

[Startrek]

Thanks Gary,
Imaging broadband targets from Sydney’s heavy LP gunk is certainly a battle, not to mention neighbours floods being left on most of the night , however Im very fortunate to image from my South Coast NSW NexDome Obs under beautiful Bortle 3 skies
My laptop screen in Sydney when the subs come in are virtually green whereas down in the Obs the screen is nearly black
It’s simply chalk and cheese
Cheers
Martin