Globular Cluster VVV CL001 and the much brighter UKS1 (m17.3)

[Dennis]

I was digging around in the bowels of ST4 Imaging and came up with the faint GC UKS 1 at mag 17.3 using the Database Power Search.

I managed to record a dim trace of UKS 1 along with the more recently discovered VVV CL001. These are very faint bulge Globular Clusters in Sagittarius, heavily obscured by interstellar dust, making optical observations very difficult.

Takahashi Mewlon 210 F11.5
Tak x0.8 Reducer/Flattener.

ASI294M Pro camera, Bortle 6 skies.
·       L: 60X60 secs
·       R: 20X60 secs
·       G: 20X60 secs
·       B: 20X60 secs
·       IR742: 30x60 secs
·       IR807: 20X60 secs

Just 158 globular clusters were known to be in the Milky Way until the European Southern Observatory's VISTA survey telescope, at the Paranal Observatory in Chile, located two faint new ones, called VVV CL001 and VVV CL002. (2011). However, an Australian Amateur Astronomer (Steve Crouch) did report recording what was to become VVV CL001 sometime in 2010, before the professional discovery was announced.

Astronomers have suggested that VVV CL001 is gravitationally tied to UKS 1, which could make these two objects the Milky Way's first binary globular cluster pair, ESO officials said. But this could simply be an effect of the telescope's line of sight, which could be distorting the true distance between the clusters.

Since interstellar dust absorbs and reddens starlight, this newly found pair is quite faint, which explains why they have been hidden for so long. Up until a few years ago, the UKS 1 cluster, which was discovered in 1980, was the dimmest known globular cluster in the Milky Way. However, it easily outshines those found by VISTA.

I have included a PanSTARRS image to show the location of these faint GC’s.

My image is the one that does not have the blown out brighter stars.

Cheers
 
Dennis

   

   

[theskyhound]

Wow Dennis. That's cool. Nicely done!

[PMSchu]

Wow Dennis, just Wow! VVV CL001 is so close to the detection limit. No wonder that it remained undiscovered for so long.

Very impressive work that you were able to image it.

Phil S.

Edit: You might want to edit the Thread Title to read VVV CL001, not VVV GL001.

[razvan]

Well done, Dennis! Thanks for the interesting post as well! It reminds me of a quote from a lecture by Hubble: "With increasing distance our knowledge fades and fades rapidly. Eventually we reach the dim boundary, the utmost limits of our telescope. There we measure shadows, and we search among ghostly errors of measurements for landmarks that are scarcely more substantial".

[theskyhound]

That's an awesome quote

[Dennis]

Here is the Luminance Frame and the IR742 Frame, which illustrates how "reddened" these GC's are.

Cheers

Dennis

Luminance Filter
   

IR742 Filter
   

[PMSchu]

It's fallen off the edge of the visible spectrum. A Type O emulsion photographic plate (blue sensitive) would be totally blind to this radiation. No wonder it took so long to discover these objects. Red sensitive plates would do better, but still, it doesn't look like there's much signal to work with.

Phil S.