M83 Southern Pinwheel Galaxy Ha LRGB ( under Sydney’s SkyDome )

[Startrek]

I’ve been working on this project since January and finally gathered enough data to fashion some sort of image above all the heavy noise gradient . Every time the new moon comes around cloudy nights appear and then disappear when the moon’s up.
Another 8 or 10 hours would be great but clear new moon nights have been rare in the past 6 months. I just wanted to complete this project and move onto other targets.
Last time I imaged M83 was back in 2023.

Bortle 8 City Suburban location
New Moon period
Seeing conditions average to good

Telescope 8” f5 Klaus Helmerich Carbon Fibre ( Self Built ) focal length 1050mm.
Mount Skywatcher EQ6-R Pro
Imaging camera ZWO2600MM cooled to -10C , Gain 0 for LRGB and Gain 100 HCG for Ha
TS Optics GPU coma corrector with Beamtech 15mm spacing ring
Antlia LRGB and Ha 3nm filters
PHD2 Multistar guiding ( 0.40 to 0.50 arc sec total )
Orion 60mm guide scope with helical focuser
ZWO EFW 7 x 2”
ZWO EAF focuser
Tracking and Goto EQMOD and Stellarium
Aquisition and Capture , APT

Luminance 336 x 30sec dithered subs
Red 160 x 30sec dithered subs
Green 138 x 30sec dithered subs
Blue 149 x 30 sec dithered subs
Ha 61 x 2 min dithered subs

Full Calibration Suite
Darks from Library
Flats for LRGB and Ha
Flat Darks for LRGB and Ha

Total integration 8.5 hours

Subs reviewed in ASTAP

Data analysed, calibrated , stacked and aligned in ASTAP

Post processed in Startools version 1.8 via Compose module using Luminance / Color : L + Synthetic L from RGB , RGB.

Startools SV Deconvolution PSF module was used with default settings only.

NB: This image is presented as documentary astrophotography and does not use any AI enhanced or AI assisted technology during post processing.

Link to Astrobin for full resolution….,

https://www.astrobin.com/full/4vy31b/0/

Attached original frame and cropped frame versions


Thanks for Looking

Comments most welcome

Martin

[strongmanmike]

Nice work from under that light and thunder dome of yours, it's a great galaxy, love all the rubies :thumbsup:

Mike

[Leo.G]

WOW, the stars are pin point right to the edge of frame, remarkable image Martin!

[gregbradley]

Very nice. The image of the galaxy looks a bit transparent though.

Greg.

[Startrek]

Thanks Mike,
The Ha definitely brings life to the galaxy

Cheers
Martone.

[Startrek]

Thanks Leo,
Much appreciated
You wouldn’t want to see my stars without my TS Optics GPU coma corrector, chalk and cheese, a quality piece of optics. A stable atmosphere with tight guiding helps too.

Martin

[Startrek]

Thanks Greg,
The cropped versions will always look transparent as the images sizes are significantly smaller. I’m only imaging at 1000mm so the galaxy is tiny in the frame. I crop them for a larger view which in turn affects the depth and transparency of the image. A 1000mm 8” scope is not exactly ideal for Galaxy imaging directly under Sydney’s heavy LP, but we do our best. My luminance subs unfortunately were captured with some moon around low in the west so again SNR was affected.More clear moonless nights would improve the image overall, 8 hrs is barely enough at my location. Down south at the Dome is obviously a completely different scenario.

Cheers
Martin

[Dave882]

Another lovely image Martin. Great detail and the structure of the spiral arms is really well resolved. The full field shows off a lovely star field and great colour. Bit of noise is apparent but even so, and especially given the LP you’ve come out with a great result. Well done!

[Startrek]

Thanks Dave,
Much appreciated !!
Yeh not bad for an 8” under that mammoth flood light called Sydney’s light dome , but the 10” down south under pristine skies is chalk and cheese.
Narrowband is a luxury , Broadband is bloody hard work especially Mono imaging.
Cheers
Martin

[Davidpmcadam]

Very nice Martin.

[Startrek]

Thanks David,
I’d like to add more data but new moon cloudy nights seem to be the norm on the east coast and a busy life in retirement gets in the way sometimes.
Hope your rig is ready to do some guiding soon.

Cheers
Martin

[TrevorW]

Martin suburban skies are not really a bane when you get plenty of data and process well :)

[Startrek]

Trev,
Totally agree, but Mono broadband imaging under B8 requires a lot of clear moonless nights to capture loads of data for each filter (Ha LRGB) and the East Coast is notoriously inconsistent.

I image from both B8 and B3 , there’s simply no substitute for dark skies in either Broadband or Narrowband , Moon or No Moon.
Broadband window of opportunity under B8 is only around 12 nights per month and the odds of scoring even 2 or 3 clear nights per month during New Moon in Sydney is quite low.
West of the great dividing range in NSW , you’re looking at significantly more consistent clear nights per month, and the further you head west the more consistent and darker.
Thankfully Narrowband is obviously no issue , in fact I’m currently imaging NGC 3567 under a full moon now with my 3nm filters.

Cheers
Martin

[TrevorW]

Generally speaking light pollution is fairly well negated by current filter technology, but in focusing and image quality is affected more so by high humidity, smoke haze and other issues that induce noise. Often image quality is markedly improved during cold cloudless moonless winter nights. Most of us don't have the luxury of dark sky sites nor as in my case an immoveable setup :)