Messier 4 Globular Cluster in Scorpius + Giant Red Friend (Sigga)

Messier 4 Globular Cluster in Scorpius + Giant Red Friend

M4 is a magnificent large apparent size globular cluster located amongst the rich Milky Way star fields of the constellation of Scorpius. With an apparent magnitude of +5.6, it can be spotted with the naked eye from dark sites. Even the simplest optical aid reveals an obvious non-stellar fuzzy object. In addition, not only is M4 bright but it's also one of the easiest globulars to find. It's located just 1.3 degrees west of striking red giant Antares (α Sco – mag. +1.0), the brightest star in Scorpius.

M4 was discovered by Philippe Loys de Chéseaux in 1746, who listed it as number 19 in his catalogue. It was also included in Lacaille's catalogue as Lacaille I.9 and subsequently added by Charles Messier to his famous list on May 8, 1764. M4 holds the distinction of being the first globular cluster ever to be resolved into stars by a telescope. Messier himself achieved the task, describing it "as a cluster of very small faint stars". Incidentally, this was the only globular cluster he could manage to resolve with his modest instruments.

The reason why M4 is bright and large is simply due to distance. At only 7,200 light-years it's a stone's throw away, making it one of the closest globular clusters to our Solar System. Currently the only other real contenders for the title of closest globular are NGC 6397 in the far southern constellation of Ara, which is about the same distance as M4 and recently discovered (in 2006) FSR 1767 globular at an estimated 4,900 light-years.

--Freestarcharts

I take this back in June, 3x300 seconds RGB. Originally have all sorts of optical artifacts, banding, reflections and such plus almost full moon too close in azimuth, so do some study and try new software IRIS and now at least acceptable if not great. This is image #41in long term project to photograph the complete Messier catalog.

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

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Status	Advanced success
Started	...
Astrometry.net job	2294112
PixInsight job	F2XRDM6RP5MH6N7VTKW6IXSGYWB0ZD9N
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	16h23m24s.53
RA (top/left)	16h32m19s.28
RA (top/right)	16h31m21s.53
RA (bottom/right)	16h14m40s.51
RA (bottom/left)	16h15m15s.73

Dec (center)	-26°32′53″.10
Dec (top/left)	-27°41′17″.7
Dec (top/right)	-25°07′21″.2
Dec (bottom/right)	-25°22′29″.4
Dec (bottom/left)	-27°56′44″.2

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