Sombrero in colour, with lots of tiny friends

[Placidus]

This is the one we've been hoping for.

Full size image here
(https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-NLJ4Q5v/0/2895678d/O/Sombrero%20L%205h30%20RGB%2045%20mi n%20each.jpg)
Here we've added RGB (45 mins each) to our recent 5hrs 30 min of luminance.

The Sombrero is unbelievably bright in the core, and we had to confine ourselves to 15 minute subs in order not to burn it out.

Since the colour data are unbinned and seeing was pretty good, we've added it in pro rata into the luminance channel. We're delighted at the number of tiny galaxies that are now remarkably clear and sharp.

A note on the colour: The Sombrero is often shown to be quite bluish. That is not how it came out for us, for good reason. The Sombero is not a spiral galaxy with a truly giant halo. It is best understood as an elliptical galaxy that has taken on a new lease of life after absorbing intergalactic gas and dust, and produced a new small spiral galaxy within it, in-situ. Thus, we would expect the halo to be very large, and to look like any ordinary elliptical galaxy: lots of very old, cool stars, and hence salmon pink.

A further note on the relative sizes of the halo and core: We suspect that many photos out there, aiming for very high contrast, have made the darks darker and the brights brighter, resulting in a huge nucleus and an unimpressively small halo. We've tried to avoid doing that, and instead to show that the halo really is quite huge, and the nucleus, like a Seyfert galaxy, has a tiny stellar core.

Please have a look at the full size image, where you can see very many distant, unrelated galaxies, mostly edge-on spirals, one or two beautiful face-on spirals showing considerable detail, and a couple very faint unshaped galaxies that are perhaps of the dwarf magellanic style.

Edit:

In response to kind feedback, we've produced a version with slightly more wavelet sharpening. This much sharpening starts to interfere with the point-like nature of the core.

Sharper image here. (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-jxRLsHx/0/0bce2a73/O/Sombrero%20with%20additional%20wave let%20sharpening%2C%20core%20blown. jpg)

Very best,
Mike and Trish

[Stevec35]

Well you blew me away guys. Very nicely done indeed.

Cheers

Steve

[Placidus]

Thanks muchly Steve. You also got the warm colour, the truly huge halo, and the dot-like inner core.

Best,
MnT

[croweater]

Don't usually post on photos much guys but this best sombrero I've seen. Started to count the other smaller galaxies but gave up. :thumbsup: Cheers Richard.

[Andy01]

Wowee!
Can’t wait to get home & see this baby on a big monitor,
Looks amazing on the iPhone though :thumbsup:

[billdan]

Well done M&T, a wonderful image of the Sombrero, lovely star colours and heaps of remote galaxies.

Cheers
Bill

[Atmos]

Amazing MnT! As others have said... spectacular!

[Placidus]

Thanks, Richard :hi: nice to hear from you.



Thanks, Andy. Have dinner first!



Thanks Bill, glad you like it.

Best,
MnT

[Placidus]

Thanks, Colin! That's very kind.

MnT

[LewisM]

It's lotsa good right there.

[atalas]

:eyepop:yeah excellent guys....very deep too! :thumbsup::thumbsup::thumbsup: thanks for the little write up too....a couple of facts about the Sombrero I didn't realize!

[Peter Ward]

Delightful results from that photon hoover...as usual :)

I'll be picky and say it's a little soft...but oh so wonderfully deep.

:thumbsup:

[alpal]

Hi Mike and Trish,
Wow you've gone deep - with so many other galaxys.
I also like the star colours that have come out.
I'm not sure but I think you could have slectively sharpened
some of the Sombrero along that dust lane &
the area in behind it - that flat part of the disk?

cheers
Allan

[Placidus]

Ta, Lewis.



Thanks, Louie. I'll dig up a reference later.



Thanks, Peter. Your images are always so crisp and crunchy. I'll try a separate version that's a bit firmer.



Thanks muchly Allan. Actually we've already done some very gentle selective sharpening of just that region. I feel Mike Sidonio watching carefully, lest I overdo it, but as I said to Peter, I might try a separate version.

Best,
Mike

[DJT]

Wow! Well done MnT. I can see why you are excited about this.

Absolutely besmirched in little faint fuzzies.

Looking at this edge on it does look as if the galaxy is concave, like a dish. Really very cool.
:thumbsup:

[Lognic04]

Awesome!!! :eyepop:

[RickS]

Masterfully done, M&T :thumbsup: I love the all-encompassing halo and the field 'o fuzzies. I'd agree with Peter's comment that it's just a little soft.

Cheers,
Rick.

[Placidus]

Thanks David and Logan.



Hi, Rick, and thanks! We can see we must do a slightly more sharpened version straight away on the morrow.

Best,
MnT

[PRejto]

Wonderful result!!!!

I rather like the softness; it fits well with fuzzy undefined halo. If it get's too crisp I think it might start to look "processed."

Bravo,

Peter

[topheart]

Excellent ! Very very beautiful colours.
Hat's off to you!
Cheers,
Tim

[Placidus]

Thanks Peter for encouragement and a refreshing view. One worries in particular that if one makes it too crisp, detail starts to appear that is not in the sky.

Scylla on one side and Charybdis on the other, the devil behind and the deep sea below.



Thanks so much Tim.

Best,
MnT

[Andy01]

Looking at this on the hi-res monitor now. :)

It's georgeous, wonderful star colours and dynamic range, lots of amazing little galaxies in the background, classy image processing indeed :thumbsup:

One compositional niggle though, the hero seems just plonked in the centre of the frame. There have been other published versions of this subject that use the supporting stars to balance the image as well.

Just a thought.:question:

Again though, a top shelf image :party2:

[multiweb]

Good stuff Mike. Lovely colours. Heaps of faint fuzzies too. :thumbsup:

[Placidus]

Thanks for the kind comments and taking the time to take an artist's view too. We ache because there are some exquisite, very bright, and intensely colourful stars just out of field. If we live long enough, we might have to consider a mosaic.



Thanks Marc, and lovely to hear from you to, friend!

- - - - -

Oh, good news with the replacement Honda EU30iS generator. It has both two-wire and wireless key-fob remote start/stop. We carefully measured the power consumption of the gear last night. We were very surprised. The whole observatory (two big screens on, cameras cooling, 160 Kg dome rotating, shutters opening, lights on, etc) uses about 250 watts, but once all is set up, it only uses 190. A 600AH battery would see us through the longest winter night and be only 40% discharged. So we're going to see the solar power folk at Lucknow about a system where it recharges in the daytime, but the generator will kick in automatically if it's too cloudy and not recharged by say 4pm. It will pay for itself in about 4 years in saved fuel. But the big thing is it means we could contemplate remote operation from the house when we're a few years older and greyer.

Best,
MnT

[gregbradley]

Congrats on a truly superb image.
I like the way the stars are evenly coloured and no colour rings which tends to plague filtered imaging.
As far as sharpness goes you probably left a bit on the table but I also agree its a fine line between sharpened and an overly processed look.
The big halo looks great and the galaxy colour looks spot on to me.
One if your very best images.
Everyone likes a good Sombrero!
Greg

[Camelopardalis]

Beautiful M&T :thumbsup: love the little spirals too!

[John K]

Mike and Trish,

congrats on your image! Really like the colours you have achieved.

I counted almost 20 galaxies in your field which really puts things in perspective.

Clear skies.

John K.

[Placidus]

Thanks so much, Greg. We've seen a few really beautiful Sombreros in the last week or so. Technology has come a long way. Oh to have access to a machine at high altitude!



Thanks, Dunk!



Thanks, John.

Best,
MnT

[Placidus]

Greg, Rick, Allan

I've had a go at some further wavelet sharpening. Despite best efforts with automatic masks and even PhotoShop finger painting on masks, either the core blows or it starts to look totally weird. My best effort is here. (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-jxRLsHx/0/0bce2a73/O/Sombrero%20with%20additional%20wave let%20sharpening%2C%20core%20blown. jpg) Not sure that I like it.

Cheers,
Mike

[marc4darkskies]

Excellent M&T! :thumbsup: :thumbsup: Beautifully deep and rich colour. To split hairs, I would have expected it to be a teensy bit sharper.

[SimmoW]

Wow that really does look concave, and great edge detail, great work MnT

[willik]

Very nice image but it looks slightly out of focus or needs to be
a bit sharper on detail.
Martin

[Placidus]

Thanks muchly Marcus.



Cheers, Simon.



A number of people have commented that the image seems a little soft, or even out of focus. The raw FWHM was about 2 sec arc, which is reasonable for our altitude (660m) at this time of year. We refocus every 3 subs.

As for local contrast, I suspect that folks missed our previous reply, in which we pushed the wavelet sharpening a bit past where we felt truly comfortable.

Sharper image here (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-jxRLsHx/0/0bce2a73/O/Sombrero%20with%20additional%20wave let%20sharpening%2C%20core%20blown. jpg)


A good test of true sharpness is the ability to resolve a close double. In the attached, we bravely compare with seven other utterly superb images by leaders in the field using excellent (but widely differing) technology under similar circumstances.

Please in particular observe the very tight double, roughly central or just above central in the image, and at the extreme left of the galactic disc. These stars are approximately 2 seconds of arc apart, easy to see visually but hard to photograph under 2 sec arc seeing.

Clearly Peter Ward's Alluna with adaptive optics wins, hands down. Ours is pretty much in the middle, neither better nor worse than average, and therefore definitely not blurry.

Please also observe the very faintest background galaxies in each image, and the grittiness of the background.

Folks are right that there are sharper images out there, but I very much doubt if we, with our gear, in our situation, could do hugely better for sharpness. At our altitude of 660 meters, a scope larger than about 8 inches is very much limited by the seeing, not the aperture.

In conclusion, while our gear and our techniques aim for depth rather than sharpness, we think we are middling sharp for our altitude without the use of adaptive optics.

Very best wishes,
Mike

[PRejto]

That's a fascinating comparison. To my eyes you certainly "win" in terms of depth. On a side note are you ever tempted to add AO to your gear?

Peter

[Placidus]

Thanks, Peter.

We've seen some amazingly sharp images with AO, so yes, it is very tempting. I've always put it in the too-hard basket. I suppose what I would do physically is remove our off-axis guider, which uses up about 25 mm of the back-focus, and replace it with an off-axis guider. But the thing that worries me is how often we'd get a guide star that would give us 8 frames a second. Perhaps it's time to start talking to people who've used one on a similar scope to ours.

Any help welcome!

Best,
Mike

[RobC]

Great Image M&T . I also think yours is tops.

Cheers

Rob

[Placidus]

Thanks for the kind words Rob, but while it's deep, and middling sharp, it isn't so razor sharp.

Perhaps we should stick to photographing great big ridiculously faint things like the outer chevrons of the Helix, rather than tiny but super-bright things. Or perhaps we should consider throwing out tens of thousands of dollars worth of Aspen camera, home-made off-axis guider, and 50 mm square ten position filter wheel, and go to
something along the lines that Tim Caruthers uses (SBIG self-guiding camera controlling an AO-X) is the way to go.

Apart from the money, there's the emotional investment. I've written every last line of software that controls our observatory, cameras, cooling, acquisition on main and dual guide cameras, filter control, mapping, catalogues, synch and goto, tracking, guiding, focusing, the lot, so it is all fully automated, even working the dome and shutters, and turning off the generator in the morning. To go back to SBIG again would mean either scrapping all that, years of work and the whole way of operating, or to learn how to use their current DLL to do the camera control myself. (I am familiar with a much older version). The Aspen camera also has superior cooling which is very important for faint targets in summer.

On the positive side, the Aspen camera has a couple nasty habits: it has very bad after-images, and the brighter stars "drip" a little. Although the SBIG camera has exactly the same chip, perhaps they do it better.

Nah. Do the new living room and the conservatory first. There goes the budget for the next 5 years. We'll stick to big faint things.

Cheers,
Mike

[Gnat]

I just projected your photo on the big screen TV. Had a ball finding the galaxies captured in your photo and zooming in on the dust lanes and the stars on the right in the spiral arms. Great capture.

[PRejto]

Mike,

With your brains I think you could "easily" build your own AO along the lines of the SX-AO. It's just a thick clear window with 4 motors controlling tilt. It can be placed just about anywhere in the system...even quite far away from the CCD and it can use any guide camera.

Peter

[topheart]

Hi Mike,
Interesting discussion and comparison. I think you are doing great as you are and it is so much work and expense to swap everything out....so assessing the benefit would need to be done very carefully....maybe I can formally assess the difference with and without the AO-X for you on a few typical nights, perhaps when the full moon is interfering with serious imaging....let's see if I can setup a scientific comparison. Also, I forgot to mention I have a 0.6 reducer in the light path to the off axis guider, so the FOV of the guider is a bit bigger and the stars a bit brighter....so the OAG sees 0.6 of the 4.7M focal length of the main scope.

Cheers,
Tim

[gregbradley]

Gee whiz I think this discussion has gone off the rails a bit. Sombrero is a small galaxy, the elliptical is large but the spiral is 1/3rd the size of the Milky Way. So your image is not "soft". You've gotten depth, great colour with very low noise and a nicely detailed image.

There are techniques like multi layered Decon that can help but as you know and many have commented, heavy sharpening techniques don't come free. There is usually some damage. I think the best processing choice is to keep it looking natural, do some sharpening/contrast improvement just before it becomes noticeable and then that's the limit.

So don't falsely conclude you should only do faint objects as this is a stand out image. As you say longer focal length scopes are heavily affected by seeing. I just did some more time on the Sombrero myself over the weekend to add to mine. It was softer than the original data which was taken on better seeing nights. Seeing wasn't bad just not as good.

On my CDK17 I have had seeing affect it so much that when the seeing was bad I could not even focus the scope as it would go in and out of "focus" even when I had not changed the focus at all.

Greg.

[Ryderscope]

This is a stunning image MnT. The original version has my vote as it presents the data and the image “as it is” resulting in a beautiful galaxy that looks to be floating in space (which it is of course).

[RickS]

Thanks for the analysis and explanation, Mike! I just happen to have some data on the Sombrero myself and it will be interesting to compare when I finally get around to processing it.

FYI, Martin Pugh is using an AOX on his CDK17 at Yass and getting remarkably small FWHMs on good nights.

Cheers,
Rick.

[PKay]

Now my monthly background image.

As an aside, I have kept an image taken by that telescope that orbits our planet. You have matched that, and more...

Thank You MnT.

[Placidus]

Thanks muchly, colleagues. We've been out shopping for treated pine, yoghurt starter, and other goodly things.



Cheers, Natalie, that's kind. Love the nickname.



Spent much of the day thinking about that. We control the RA and Dec motors at 2250 Hz, so 10 Hz sounds easy! Ahem. How hard can it be, as they say on Top Gear.



Thanks for a very thoughtful comment, Tim. It would be truly wonderful, as a thing in its own right, to make use of a full moon evening and do a set of say 10 alternating subs with and without AO. Many would love to see the result.



Thanks very much for that, Greg. You've steadied the horses a bit.



Hi, Rodney! Thanks for the cheery vote of confidence in the gentle approach.



Ta, Rick. I should write to Martin and ask about his set-up.



Thanks, Peter. That's very encouraging.

Very best,
Mike and Trish

[topheart]

No worries....as long as I have a bit of free time around the full moon, then I will give it a go.
Cheers,
Tim