Deep Sky Object in Summer
M4 (Globular Cluster in Scorpius)

Date & Time: Apr 12 2003, from 27:07 to 27:12 JST(+0900)
Composed 2 shots with 4 minutes exposed
Optical: VIXEN 20cm(7.9") VISAC with conversion lens (f=1278mm, F6.4)
Auto-guided with TAKAHASHI JP Equatorial & Meade Pictor 201XT
Digital Camera: Fujifilm FinePix S2 Pro
Location: Ooizumi vil., Yamanashi pref.

Camera Settings: Recording Format...12bit CCD-RAW, converted to 16bit TIFF(3024×2016)
CCD Sensitivity...ISO1600, White Balance...Auto

M4 (NGC6121) / Globular Cluster, type IX
R.A.16h 23m 36.0s (2000.0)
Dec.-26° 32' 00" (2000.0)
Apparent Size14.0'
Real Size95 light yrs.
Distance7000 light yrs.
A globular cluster located just one degree west of Antares is M4 (NGC6121). It's very close from the Antares, so we can find easily the cluster with binoculars, but without a larger telescope it will not appear very spectacular.
M4 is characteristic as its reddish color although we cannot detect the peculiar colors in almost all of other globular clusters.
The cluster consists of about 10 thousand stars, and about seven thousand light years away.

Wide-field image around M4 & Antares (70KB)



Copyright(c) 2003 by Naoyuki Kurita, All rights reserved.
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