UKS-1, The faintest globular of the Milky Way

[SkyViking]

This image shows UKS-1, the faintest globular cluster in the Milky Way. UKS-1 is located in Sagittarius at a distance of 27,100 light years and is one of the globulars lying closest to the galactic centre at only 2,600 light years.
Because of its location it is very heavily obscured by the great masses of interstellar dust in the direction of the galactic centre and it has one of the highest extinction ratings of any known globular cluster (B-V = 2.93).
The combined visual magnitude of UKS-1 is thus only 17.29, and the brightest individual stars shine at magnitude 25.5, making it a strictly photographic target only.
However, it has been reported by Barbara Wilson and Larry Mitchell that under extremely dark skies UKS-1 can in fact be observed visually, with great difficulty, using a 36" Newtonian. You can read about their findings here: http://astronomy-mall.com/Adventures.In.Deep.Space/obscure.htm

For this image I used unfiltered exposures with the ToUCam in order to also capture as much of the infrared light as possible.
The position itself of UKS-1 was relatively easy to find in the 10", with plenty of stars and asterisms in the area to use as a guide. I was also familiar with the area already because I had recently imaged another obscure globular Terzan 5 which lies nearby (see this thread: http://www.iceinspace.com.au/forum/showthread.php?t=62509). Of course nothing was visible in the eyepiece, but just a quick 3 second exposure with high gain did reveal UKS-1 as an extremely faint blob on the computer screen.

Image is here: http://www.pbase.com/image/125730719

Image details:
Taken on 17/06/2010 with 10" Newtonian and ToUCam Pro SC1.
43 x 30.5s, No guiding, no filters.

Hope you enjoy. It was great fun imaging this one :)
All comments, critique etc. are welcome.

Regards,
Rolf

[renormalised]

That's amazing Rolf....a 10" with a webcam....brilliant shot!!!:)

[JD2439975]

That sure is a faint little sucker Rolf, could probably use a bit more time on it to really bring it out though.
Mag 25.5 for the brightest star! dark skies are a must have for this one eh.

Love seeing the unusual objects & just what a webcam can do, nice one.

[Dennis]

Fantastic work Rolf! Well done!

Cheers

Dennis

[dugnsuz]

Great effort Rolf
You set yourself some challenges in your imaging - kudos!
Doug

[David Fitz-Henr]

That's a very interesting shot Rolf - unusually faint object captured with a Webcam! Great shooting!

[PeterM]

Rolf its an 11 out of 10 from me, fantastic, just great to see amateurs pushing the boundaries and delivering stuff that is way off the beaten track.
PeterM.

[strongmanmike]

Wow that's very cool Rolf.

You have some other interesting images on your web site. The Abel 1689 cluster shot is great. It's not the incredible distance that fascinates me so much but rather the fact that the light flux even after spreading out so thin over all that distance is still high enough for a 10" mirror to collect enough of it to be seen ...they must be bluddy bright wopping galaxies :eyepop:

[SkyViking]

Thanks Carl, I wasn't sure if I could pick it up but there it is :)


Thank you Justin :) Yes I enjoy doing the more unusual targets until I get a bigger CCD so I can compete with all the M42 and Eagles out there :) But when I get that I'll most likely keep pointing it at obscure targets... ;)
This one is really at the very edge of what I can image. It was mostly an exercise in extracting it from the background so I probably won't add more data to it, although it never hurts of course.



Thank you Dennis, glad you liked it :)



Thanks Doug, yes this one was definitely a challenge! :eyepop:



Thank you David :)



Thanks Peter, yes it's always a pleasure to hunt down these obscure targets. Glad you enjoyed it :)



Thank you Mike :) I love your M104 with globulars by the way.
I would be very interested in seeing your version of Abell 1689, you must be able to get a real stunning image with that new super camera of yours! :)

[JD2439975]

I'll second that...again. :lol:

[strongmanmike]

Hmmm?..I had a look at the proposed FOV in Star Atlas Pro and I think it would be a disspointing shot with such a big chip. The galaxies are tiny and there are no biggish members :shrug:...Next time I am out I might snap a 10min sub just to see...if I get out before Virgo gets too low that is :rolleyes: :sadeyes:

[mental4astro]

Rolf, top shot, mate! With a webcam too! What a hoot.

One thing that impresses me about it is that there is a hint of structure and detail within the shot. Might just be an artifact, yet the shapes shown are tantilising.

Did you know that UKS-1 was a target object in this month's Obs. Challenge. An invitation had also been made to the imaging fraturnaty to have a go at picking of this faint bugger as a visual sighting would be highly unlikely.

There is another faint, approx. mag 15.5, GC being offered up as part of the imaging invitation. Keen to have a go at it? After this puppy, it should be 'easy', :lol:. Have a look in the Observational and Visual forum fot June's Obs. Challenge.

Alex.

[SkyViking]

Thank you very much Alex. I think there is definitely structure in there, not much but it's there.
Didn't know about the challenge so that's a complete coincidence :D I'll keep an eye on the challenge thread in the future. Where can I see invitations by the way?

I might have a go at AM1 then, after UKS-1 it'll nearly fry my chip - maybe I should put a moon filter in the path for safety ;)

Regards,
Rolf

[SkyViking]

Go for it Mike :) Looking forward to the results!

[mental4astro]

The invitation is at the beginning of both the June Obs. Challenge and the new Imaging Challenge sticky:

http://www.iceinspace.com.au/forum/showthread.php?goto=newpost&t=62129

http://www.iceinspace.com.au/forum/showthread.php?t=61839

"Moon filter", I'd say solar at least!

Alex.

[sjastro]

Rolf

Well done on the UKS-1 image.

AM-1 is not going to be as easy as you think. The challenge with AM-1 is to show an image of the resolved cluster.
At 1.2 arcmin diameter you will require some seriously large FL.

I have been able to image and resolve AM-1 using a FL of 2800mm under some very good seeing conditions.

Regards

Steven

[SkyViking]

Thanks Steven :) It'll be interesting to see how AM-1 turns out when I get around to imaging it, hopefully I can resolve it somewhat but only time will tell :)