Recently I have provided the international team of professional astronomers led by Dr. David Martinez-Delgado, of Stella Tidal Streams fame, some of my deep NGC 253 data for an impending paper on the faint but huge halo around NGC 253 and I thought some on here may like to see my recent reworks for them, to show this feature
Seen in negative and enhanced luminance it is easier to appreciate the huge size of the very faint extended halo, which in this deep exposure, stretches across 3/4 of a degree of the sky or one and a half times the diameter of the full moon..that's a big galaxy! There is a fair bit of even fainter Milky Way Cirrus dust revealed too.
Its worth noting, this faint feature was revealed with 265min of Luminance data from a reasonably dark sky using a fast 12" Newtonian.
Full image calibration was performed (Darks and Flats) and no targeted local brightening was used in the processing to artificially highlight the halo, all actions were applied globally so the structure and shape is not arbitrary or artificial.
Bah, congrats not necessary mate, just of interest . I also gave them the raw calibrated Lum and Blue fits data for photometry so be interesting to see what comes out of that.
Excellent work, great to see your passion turned into a useful scientific advance. I think we'll see more amateur contribution to astronomy in the future, notwithstanding the rise of the mega-telescopes, simply because there are so many amateurs with equipment today that is rivaling professional-grade equipment of just 1-2 decades ago.
Great work Mike. I have known for some time virtually galaxies are much larger than is usually displayed in our imaging. It stands to reason the star density fades out the further away from the gravitational core of the galaxy rather than a sudden boundary. I've noticed that in my own images.
Cent A was a good example of that. M83 has a wider halo as well. I guess its too faint for most scopes to pick up and Hubble I think tends to do relatively short exposures.
Stunning Mike. I like the way you explained that you've avoided local "finger painting" which could produce an artificial halo.
I agree with Greg that in principle no galaxy or nebula really has an outer "edge", because there will always be some atom somewhere that has enough energy to escape to infinity.
Mike, yes like decon can be, selective brightening of faint features is usually pretty obvious. Hey, I think it is perfectly legitimate and I've done it on the odd occasion, in say a bright busy neb image for example simply for aesthetics to highlight features who's shape is already clearly defined and obvious but doing it to supposedly "reveal" faint extended features is inaccurate and basically pretending. I've seen obvious selective brightening in, for example, images of NGC 1097 to reveal its jets and Centaurus A to try and show the outer hocky stick shaped halo, it is always pretty obvious. In this 253 case of course it was for scientific purposes so any such thing was definitely a no no
That's fantastic Mike, congrats on the achievement.
Extended halos are probably much more common than we realise, it's just a matter of exposing long enough to pick up the details - something which the professional scopes often cannot do.
Looking forward to the paper
Oops sorry Ron I didn't respond directly to this, yes I did see that thread
Quote:
Originally Posted by SkyViking
That's fantastic Mike, congrats on the achievement.
Extended halos are probably much more common than we realise, it's just a matter of exposing long enough to pick up the details - something which the professional scopes often cannot do.
Looking forward to the paper :thumsup:
Cheers Sir Centaurus A
Quote:
Originally Posted by cometcatcher
Wow, that is very cool to be involved in such a project.
Dr Martinez-Delgado asked for it like that, so I can't really claim the idea this time 
