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View Full Version here: : NGC 5139 Omega Centauri under a Waning Moon


Startrek
23-04-2025, 04:38 PM
Last Friday evening presented a clear stable night with a 70% waning moon rising in the east. Due to my restricted field of view from the South to West up to 60degrees and knowing cloud was arriving the next evening into the week, I decided for a quick capture of the big daddy of Globular Clusters NGC 5139 Omega Centauri as it was on my list this year.
This is the first time using only 20 sec subs with the ZWO2600MM camera at Gain 0 under my B8 Skies with a rising moon.

Atmospheric Seeing Conditions : Very Good to Excellent
Skyglow Bortle 8 Skies
70% Waning Moon
Telescope: 8" f5 Klaus Helmerich carbon fibre Newtonian ( Self Built )
Mount : Skywatcher EQ6-R Pro
Imaging Camera: ZWO 2600MM cooled to -10C , Gain 0
Guide Camera: ZWO 120MM-S
Guide Scope: Orion 60mm with Helical focuser
TS Optics GPU Coma Corrector
Antlia LRGB Filters
PHD2 Multistar Guiding ( Best guiding numbers ever recorded from this mount 0.35 to 0.45 arc sec most of the night )
ZWO EFW 7 x 2"
ZWO EAF Focuser
Tracking and Goto EQMOD and Stellarium
Aquisition and Capture APT
Lum 80 x 20 sec subs
Red 65 x 20 sec subs
Green 60 x 20 sec subs
Blue 65 x 20 sec subs
Dithered every 3rd Sub
Full Calibration Suite
Darks from Library
Flats for LRGB filters
Flat Darks for LRGB filters
Total integration 1.5 hours
Subs reviewed in ASTAP
Subs analysed, calibrated,stacked and aligned in ASTAP
Post processed in Startools V1.8 via Compose module using Luminance / Colour L+Synthetic L form RGB, RGB.

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

Astrobin link for full resolution…..,

https://www.astrobin.com/full/9xjy1u/0/

Thanks for Looking

Comments Welcome

Martin

TrevorW
23-04-2025, 04:44 PM
Lovely shot that, well resolved stars and good colour with so little integration, moon is not really an issue with this target IMO, as its so bright. :)

Cyberman
23-04-2025, 06:05 PM
Very good colours, resolution and setting. Good to see some clusters being imaged. Cheers, Rob

Startrek
24-04-2025, 02:36 PM
Thanks Trev
Yep that’s why I kept my subs to 20 sec
The 2600MM is a super high performance camera , 60 sec subs would have blown out the core area with my luminance filter , not to mention wrestling with all that B8 gradient on top of moon glare gradient.
Pretty happy with the result for just over an hour.

Cheers
Martin

Startrek
24-04-2025, 02:39 PM
Thanks Rob,

47Tuc and M22 are my favourite globs as they have some unique star detail.Omega is just a big fuzzy ball of stars , still fun to image and fun to observe as well.

Clear Skies
Martin

strongmanmike
24-04-2025, 03:24 PM
That's a beauty, of a beauty, Marty :thumbsup:

Mike

DarkArts
24-04-2025, 04:32 PM
I'd got out of the habit of commenting on images, but that is a particularly sharp Omega Centauri. :clap:

gregbradley
24-04-2025, 05:21 PM
Terrific resolution there Martin.

I imagine planets near those centre stars would have no night sky.

Greg.

Startrek
24-04-2025, 10:34 PM
Thanks Mike !!

Startrek
24-04-2025, 10:36 PM
Thanks for temporarily getting back into the habit
Much appreciated !!

Martin

Startrek
24-04-2025, 10:41 PM
Thanks Greg,
Much appreciated
Conditions were exceptional that evening
I could see at least 20 stars and that a record directly under Sydney’s light dome.
I read somewhere that if our solar system was location inside the galactic bulge , our night sky on Earth would be like a gigantic Omega Centauri, super bright and littered with billions of Stars.
Gee I’m glad we are located where we are !!
Martin

Startrek
25-04-2025, 08:12 PM
Here's a crop version of my recent Omega Centauri globular cluster to venture in a bit deeper.
The cropped image still has good resolution as conditions were quite good that night. Also the image file size didn't suffer too much from the image crop, its still around 1.8MB.
Due to my restricted field of view I only had a short window of opportunity to image this object. Another hour would have been nice , but not to be. Weather has been cloudy ever since.

Astrobin link for full resolution……,

https://www.astrobin.com/full/dqpgpn/0/


Thanks for Looking

Comments Welcome

Martin

astronobob
30-04-2025, 09:49 PM
Definitely a stunning Omega Martin,
Up there with the very best,
I do like the 1st slighter wider field keeping the glob somewhat isolated from its surroundings,,,,
Beautiful resolution and colour is impeccable

Startrek
01-05-2025, 09:55 AM
Thanks Bob,
Much appreciated
Apart from a waning moon, conditions were pristine that evening. Under my B8 location generally I can only see the southern cross , pointers and the odd bright star in the sky but that night I could make out quite a few faint smaller stars and therefore excellent seeing. The guiding confirmed it , stable and tight for the whole session.
Pity my field of view is restricted from the south east to south west. Objects like the Tarantula and others, only have a short imaging window.
Cheers
Martin

Dave882
02-05-2025, 07:44 PM
Wow Martin that’s beautiful. Wonderful resolution and I’m especially impressed with the star colours that shine through even with such pinpoint profiles. Excellent processing well done

Startrek
02-05-2025, 09:09 PM
Thanks Dave
Too kind mate
A short but fantastic night in ol Sydney town
We only get a hand full of those nights a year when conditions are just perfect
My EQ6-R mount was punching well above its weight, guiding like an AP, tiny Ra pulses and Dec was almost flat lining, just a pleasure to watch.

Cheers
Martin