Messier M4


Object Information
Messier object: M4
NGC (New General Catalog) number: NGC 6121
Discription: Globular Cluster
Located in constellation: Scorpius
Right ascension in hours minutes: 16:23.6
Declination in degrees minutes: -26:32
Visual magnitude: 5.6
Size: 26.3 arc minutes
Image size: 55.23 arc minutes high by 40.98 arc minutes wide
Image orientation: North is top, East is left
Detailed discription of M4 in SEDS Messier database
Other Messier galleries, images or catalogs

Observing Log
Date of observation: August 21, 1998
Time at end of CCD image 21:11 PDT
Observing Location: ARGO
Observation of object: M4 is a large irregular globular cluster with some stars resolved to half way to center and it has a small irregular bright core.
Sky Conditions
Sky transparency: 5.3 (Magnitude of the faintest star visible with the unaided eye in Ursa Minor) The Milky Way was very bright with dust lanes.
Moon set at 19:52 PDT on August 21, 1998
Astronomical twilight ends in the evening at 21:45 PDT on August 21, 1998
Astronomical twilight starts in morning at 4:28 PDT on August 22, 1998
Observing Equipment
80 mm aperture refractor telescope and CCD Cookbook Camera
CCD image time: 1 - 60 seconds image
CCD dark calibration frames: 15 - 60 seconds dark frames

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