THE WITCH’S BROOM NEBULA (NGC6960)

THE WITCH’S BROOM NEBULA (NGC6960)

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NGC6960 known as the Western Veil Nebula taken from Al Sadeem Observatory last July 21, 2018 using Vixen ED115S telescope and ZWO1600MC-cool CMOS camera mounted on Skywatcher EQ6. 2 hours total exposure time, stacked and post-processed in Pixinsight. (Image Credit: Al Sadeem Astronomy)

NGC6960, known as the Western Veil Nebula, is a diffuse nebula located about 1470 light-years away from Earth in the constellation of Cygnus (the swan). It has multiple other designations such as the Witch’s Broom Nebula, Filamentary Nebula, Finger of God Nebula, Lacework Nebula (based on its shape resemblance) or Caldwell 34. It is a western portion of the Veil Nebula or the Cygnus Loop placed at the right wing of the swan.

It was discovered by the English astronomer William Herschel on September 5, 1784, described as a nebula “Extended; passes through 52 Cygni… near 2 degrees in length”. It lies behind the star 52 Cygni, though it is not physically associated with the nebula.

Astronomers thought that the Cygnus Loop is the product of a supernova explosion of a massive star about 20 times the mass of the Sun, as bright as the crescent Moon occurred around 8000 years ago wherein its remnant material spread out a region about 3 degrees in diameter , about six times the diameter of the Full Moon. The remnant glow has faded since then over thousands of years, becoming visible only through telescopes. Other components of the nebula can be observed in X-ray region, as it was a known of soft X-ray emissions.

Vast amounts of energy from the supernova explosion created powerful shock waves pushing through the stellar remnant material at speeds reaching 600,000 kilometers per hour, heat it up to millions of degrees Kelvin and eventually cool down through time, generating the wispy, intertwined filament structure.

Though at a relatively bright magnitude +7.0, it can’t be easily seen with the naked eye due to its low surface brightness. You need at least a 4 inch telescope or higher to spot it. When observed visually, it will only appear as a faint grayish wisp with the bright bluish-white star 52 Cygni at the center. Long-exposure photography is necessary to reveal more stars and its nebulosity, or more preferably using an OIII (doubly-ionized oxygen) filter, where most details are resolved. The nebula is situated 20h 35m 48s right ascension and 30° 42′ 30” declination. The entire nebula lies few degrees south of Gienah (ε Cygni), Cygnus’ right wing (see figure below).

Location of the Western Veil Nebula in the Sky (Image Credit: constellation-guide.com)

REFERENCES

Veil Nebula|Constellation Guide. (2014, August 19). Retrieved from http://www.constellation-guide.com/veil-nebula/

Wikipedia contributors. (2018, September 10). Veil Nebula. In Wikipedia, The Free Encyclopedia. Retrieved 23:13, October 25, 2018, from https://en.wikipedia.org/w/index.php?title=Veil_Nebula&oldid=858928717

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