LA SILLA SPOTS STAR CLUSTER W’ AN ODD DARK CLOUD.
Photo Credit: ESO/La Silla Observatory, Chile: CLICK photo for larger view and see below for links and information.
Check out this image from the European Southern Observatory’s (ESO) photo of open star cluster NGC 6520 and Bok globule Barnard 86. What you’re seeing is a very young (relatively) open star cluster of massive bright blue stars that haven’t been around long enough to wander far from the pack and spread out in their separate directions. Over time they will spread and possibly resemble M7 or M45 (Pleiades) and eventually eve further still.
That dark cloud sitting to its right (as we see it) is called Barnard 86 and it’s what’s called a Bok globule. They are very cold, dense pockets of star forming material that quite often have stars forming within them. They are so packed with dust and interstellar material that they absorb light that encounters them. When this object was discovered by American astronomer, Edward Emerson Barnard he described it as a “drop of ink on the luminous sky.” Barnard was the first to use long exposure techniques to photograph dark nebulae.
The area on the night sky that it’s located in is the densest region of stars in the galaxy. Behind this object you see almost no sky, no background galaxies at all. The area is just a vast wall of millions of stars and material near the center of the galaxy blocking all vision through it.
NAME: NGC 6520 & Barnard 86.
WHAT IS IT? Open star cluster and Bok globule.
HOW FAR AWAY IS IT?: Approximately 6000 light years.
HOW BIG IS IT?: Cluster only spans about 10 light years and the entire structure cloud included spans approximately 20 light years. It contains around 60-100 stars.
HOW OLD?: Only about 150 million years so its very young.
APPARENT MAGNITUDE?: Small telescope or binocular view away at 7.6.
WHERE IS IT? (General): Constellation Sagittarius the Archer.
WHERE IS IT? (Exact RA/DEC J2000): RA: 18h 03m 25s / DEC: -27d 53’ 28”.
European Southern Observatory (ESO) page for this photo: http://www.eso.org/public/usa/images/eso1307a/
SIMBAD data page on this object: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+6520