The "Earth" of clusters and constellations: The area imaged by Hubble contains the globular cluster ESO 520-21 (also called Plumer 6). This densely packed, more or less globular collection of stars is found near the center of the Milky Way, where interstellar gas and dust absorb starlight and make observations difficult.
Hubble Space Telescope image of a twinkling star field containing the globular cluster ESO 520-21 (also called Plumer 6).
This twinkling star field, imaged by the Hubble Space Telescope's Wide Field Camera 3 and Advanced Camera for Surveys, contains the globular cluster ESO 520-21 (also called Plumer 6). This densely packed, more or less globular collection of stars is found near the center of the Milky Way, where interstellar gas and dust absorb starlight and make observations difficult.
This absorption by interstellar matter affects some wavelengths of light more than others, changing the color of astronomical objects and making them appear redder than they actually are. Astronomers call this process "the ground", and because of this, determining the properties of globular clusters that are close to the center of the galaxy - such as ESO 520-21 - is particularly difficult.
ESO 520-21 is in the constellation Ophiuchus, near the celestial equator. The serpent theme was one of the 48 constellations that appeared in the writings of the second-century Egyptian astronomer Ptolemy, and all are among the 88 constellations officially recognized by the International Astronomical Union today. But not all the constellations proposed by astronomers throughout history have survived - among the constellations that have been forgotten or fallen out of use are Felis (the cat), Rangifer (the reindeer) and even Oficina Typographica (the printing house).
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My father, why not:
1) Link to the original article,
Can you please add the requested link? Thanks.
2) an estimate of the dimensions of the globular cluster,