PDA

View Full Version here: : Omega Centauri Widefield


Atmos
21-05-2018, 09:21 AM
My first attempt was only 20 minutes of data and I hadn't done any colour calibration as all I wanted to do was show off the faint dust in field. I've now bumped it up to a whopping 1.3 hours of exposure :lol:

I've actually done some proper processing this time though and left my laptop screaming for a lot of it. Happy with the result though, not sure there is much more I can add to it apart from getting a stronger separation of the dust from the background. I've tried to keep the dynamic range as accurate as I could do the dust isn't too bright but it is visible.

I've also, using PixelMath, tried to resolve down to the core of Omega Centauri without flattening the image with true HDR. I am still playing with CFA Drizzle Integration and not getting the results I'd like, I may have to start playing with different debayering methods. Even with 22 subs I am still getting bayer colour speckle suggesting that it is struggling to get an accurate drizzle calculation. Does it whether I do 8 images or 22 so there is some more research.

High Res Astrobin Link (https://www.astrobin.com/full/347740/0/?nc=user)

cometcatcher
21-05-2018, 10:42 AM
Oh, that's just beautiful!

h0ughy
21-05-2018, 10:47 AM
That's very nice, supple and well detailed

JA
21-05-2018, 10:48 AM
I love the gold and blue and of course the overall vista & detail. Excellent Col:thumbsup:

Best
JA

Placidus
21-05-2018, 10:54 AM
Wow! Lovely!

As a widefield study of Omega Centauri and surrounds, it is beautiful. The colour in particular is excellent.

(One of my pet peeves is the magically bright blue 10 billion year old Omega that so many people trot out because it looks pretty even though its physically impossible. You've nailed the colour).

The wide field is lovely. I take it that the IFN or dust or whatever that we can see is real? One would expect there to be some, given the direction of the image, but I've not seen it brought out before.

If one misses the point of the image and zooms in, one can start to see a lot of artifact, but if viewed from a meaningful distance, it's lovely. One of the very best top rank widefield omegas in the galaxy!

Very best,
Mike

willik
21-05-2018, 11:19 AM
Looks good Colin good detail
Martin

Atmos
21-05-2018, 11:49 AM
Thanks Kevin :P



Thanks David. I was wondering if you were able to capture the dusty parts imaging at F/2 with your new wide field imaging rig?



Thanks JA, I was hoping I didn't overdo the saturation for the gold :)



There are a lot of images of "white" globular clusters out there on the interwebs. It is a lot easier to white balance on a really wide field than it is on the globular itself. The PhotometricColourCalibration script in PI does a good job at getting the colours correct... Sometimes. I find it works well on star clusters but messes up nebulosity areas when using my unmodded DSLR.

The dust is real but you are right, it isn't imaged often. I've only seen one other image that has had it and that was Steve a few years back I believe, he got an APOD for it :P

You are right about the image break down, just one of those things you get when using a DSLR at 1.5"/pixel and trying to image higher resolution regions. Tried to drizzle integrate and run 10 passes of deconvolution BUT I am finding that deconvolving OSC images gives a very different PSF to that of a mono camera.
This is a wide field imaging setup however so I'm not expecting to even come close to the excellent resolution that you achieved on Omega Centauri.



Thanks Martin :)

Andy01
21-05-2018, 12:47 PM
Great job Colin - stars look terrific both in colour & seperation - well done! :thumbsup:

h0ughy
21-05-2018, 02:33 PM
I only gave it a short time last night as I want to get a few targets but I will give it another go yours seems to be a little bigger than mine and I would have to reorientate to get that area

Atmos
21-05-2018, 03:04 PM
Thanks Andy :thumbsup:
The stars do break down a bit at higher resolution but that could be fixed with using the QHY163M :P



Our images have a very similar orientation but they're flipped along the horizontal axis. The bright star on the right of your image (at 3 O'clock) is the same bright star on the right of mine (at 2 O'clock) and that is where the dust should be.
I'd managed to show the dust with 20 minutes at F/5.2 (https://www.astrobin.com/full/345181/0/) so I'd imagine that your one hour at F/2 should bring it up.

Atmos
21-05-2018, 03:42 PM
This is the resolution down to the core. Processing was nothing more than a heavy crop, slight histogram stretch and heavy saturation :P

LewisM
21-05-2018, 04:53 PM
Lovely Col, really nice.

One problem that MY EYES see though is the Bayer Matrix "tartan" pattern - it really stands out on my monitor and with my eyes. Maybe I am the only one, but I really can see the pattern a little too easily.

Atmos
21-05-2018, 05:23 PM
You are correct Lewis, it is there :( I am using the CFA Drizzle Integration in PI and it is leaving me with that. I am thinking it may be the debayer method (VNG or something like that) but there is a fair amount of dithering between each and every frame. Maybe I just need to turn off the CFA drizzle part and use it as an ordinary drizzle.

I did attempt to smooth that out with noise reduction but it is still visible. FAR more so in the core image I posted above as that has no extra editing.

h0ughy
21-05-2018, 06:45 PM
ok here is a very pushed image:shrug:

to be fair it is through a light pollution filter and my skies are very light polluted with sporting fields and industry, street lights and cars

topheart
21-05-2018, 07:03 PM
Well done Colin!!
Cheers,
Tim

LewisM
21-05-2018, 07:37 PM
I can see a HINT of it in Houghy's but quite a lot in Colin's.

RickS
21-05-2018, 09:54 PM
Very good, Colin. I've seen traces of the IFN in other images as well.

Ryderscope
22-05-2018, 08:05 AM
You’ve produced a very fine, detailed Omega Colin. Nice work :thumbsup: