![](\"http:\/\/spaceweekly.com\/wp-content\/uploads\/2021\/09\/A_glittering_globular_cluster_card_full.jpg\")
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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\u00a0globular 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.<\/p>\n
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\u2019s secondary mirror.<\/p>\n
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 \u2014 which astronomers refer to as extinction \u2014 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\u2019s\u00a0Wide Field Camera 3\u00a0and the\u00a0Advanced Camera for Surveys.<\/p>\n