NGC 5139 + Dust

[Atmos (Colin)]

Shot this about two weeks ago over the new moon while I was waiting for other things to rise. I had hoped on getting more data but just before I started capturing I realised that I hadn't set my camera orientation and then one or two other things happened that I cannot quite remember now. Had wanted about an hour of data but got left with 20 minutes.

As I only captured 10x120s (20 minutes) what I do find curious is that in most images on the net you don't see the dusty region to the right (well, the right with my orientation). I know my colour calibration needs some attention but I do find it interesting that many don't bring out the dust a bit more. Made it is the field size?

Anyway, here is a link to a higher res version that certainly lacks some of the nice colour definition in some higher res images (longer focal length) but I do plan on trying it with something other than a short focal length refractor

[JA]

Originally Posted by Atmos

As I only captured 10x120s (20 minutes) what I do find curious is that in most images on the net you don't see the dusty region to the right (well, the right with my orientation). I know my colour calibration needs some attention but I do find it interesting that many don't bring out the dust a bit more. Made it is the field size?

Hi Colin,

It could be a combination of a few things including limitations in dynamic range, noise, insufficient exposure, too much JPEG or other compression/resizing, excessive undersampling and/or people just wanting to process for a darker background or trying to hold the core brightness lower to see more into the core. It would be hard tell without a back to back comparison controlled for some of the variables.

Best
JA

[LewisM]

Don't worry Colin, good flats get rid of dust

[RobC (Rob)]

I cannot see the dusty region to the right . May be due to my slight degree of colour blindness. Have you tried using the Photometric Colour Calibration tool in PixinSight.

Cheers

Rob

[LewisM]

Thar be dust me hearties...

[Atmos (Colin)]

Originally Posted by JA

Hi Colin,

It could be a combination of a few things including limitations in dynamic range, noise, insufficient exposure, too much JPEG or other compression/resizing, excessive undersampling and/or people just wanting to process for a darker background or trying to hold the core brightness lower to see more into the core. It would be hard tell without a back to back comparison controlled for some of the variables.

Best
JA

You make some good points but with a mere 20 minutes of integration, that is what had me thinking that it should show up more.

Originally Posted by LewisM

Don't worry Colin, good flats get rid of dust

Or maybe flats show the dust and lack of flats don't

Originally Posted by RobC

I cannot see the dusty region to the right . May be due to my slight degree of colour blindness. Have you tried using the Photometric Colour Calibration tool in PixinSight.

Cheers

Rob

I have tried PCC in the past using a G2V reference and had varied results. I didn't even do a colour calibration on this one as I'd hoped that out of camera may have been good enough Wasn't until I got towards the end of the processing that I could see the purple cast in the core.

Originally Posted by LewisM

Thar be dust me hearties...

Wasn't until it did some heavy noise reduction on the scant 20 minutes that I could see the full extent of the dust.

[Placidus (Mike and Trish)]

Very nice image, and I like not just the dust but the odd very distant galaxy.

I was going to rabbit on about it being too blue for a globular full of cool and ancient stars, but then I saw you've mentioned that the colour is as it came.

The dust is sadly just out of frame for us, even on our mosaic version. Your wider field lets you see it. Lovely work.

Very best,
Mike

[Stevec35 (Steve)]

Hi Colin

The dust is certainly real. I imaged it back in 2006 and was lucky enough to score an APOD for it.

https://apod.nasa.gov/apod/ap060526.html

Cheers

Steve

[RobC (Rob)]

Originally Posted by LewisM

Thar be dust me hearties...

Thanks Lewis. I can discern it now.

Cheers

Rob

[topheart]

Well done Colin!
Cheers,
Tim

[cometcatcher (Kevin)]

That's lovely Colin! The dust is probably out of frame for most. Great shot!