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...ce/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/s...ad.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