NGC6717 - HST - Potw2136a
Credit:
ESA/Hubble and NASA, A. SaraA Glittering Globular Cluster
This star-studded image from the NASA/ESA Hubble Space Telescope depicts NGC 6717, which lies more than 20 000 light-years from Earth in the constellation Sagittarius. NGC 6717 is a globular cluster, a roughly spherical collection of stars tightly bound together by gravity. Globular clusters contain more stars in their centres than their outer fringes, as this image aptly demonstrates; the sparsely populated edges of NGC 6717 are in stark contrast to the sparkling collection of stars at its centre.
The centre of the image also contains some interlopers from closer to home. Bright foreground stars close to Earth are surrounded by criss-cross diffraction spikes formed by starlight interacting with the structures supporting Hubble’s secondary mirror.
The area of the night sky which contains the constellation Sagittarius also contains the centre of the Milky Way, which is filled with light-absorbing gas and dust. This absorption of light — which astronomers refer to as extinction — makes studying globular clusters near the Galactic centre a challenging endeavour. To determine the properties of NGC 6717, astronomers relied on a combination of Hubble’s Wide Field Camera 3 and the Advanced Camera for Surveys.
Credit:
ESA/Hubble and NASA, A. Sara
Coordinates Position (RA): 18 55 5.84 Position (Dec): -22° 42' 4.33" Field of view: 2.52 x 1.93 arcminutes Orientation: North is 36.7° right of vertical Colours & filters Band Wavelength Telescope Ultraviolet UV 275 nm Hubble Space Telescope WFC3 Optical U 336 nm Hubble Space Telescope WFC3 Optical B 438 nm Hubble Space Telescope WFC3 Optical V 606 nm Hubble Space Telescope ACS Optical I 814 nm Hubble Space Telescope ACS.
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NGC 6717NGC 6717 ist ein Kugelsternhaufen im Sternbild Schütze, der am 7. August 1784 von Wilhelm Herschel entdeckt wurde. Erst im Jahr 1931 erkannte Per Collinder, dass es sich hierbei um einen Kugelsternhaufen handelt. Unabhängig davon wurde der Kugelsternhaufen auch im Rahmen der Palomar Observatory Sky Survey (POSS) von George Abell entdeckt und als Palomar 9 klassifiziert. .. weiterlesen