Deep Sky Object in Summer
IC4665 (Open Cluster in Ophiuchus)


Date & Time: May 3 2019, from 25:14 to 25:30 JST(+0900)
Composed 6 shots with 3 minutes exposed
Optical: AF zoom-Nikkor 80-200mm F2.8ED (f=200mm, stop: F4.0)
with IDAS LPS-P2-FF & Kenko PRO Softon[A] filters
Auto-guided with TAKAHASHI EM-200 Equatorial
Digital Camera: Canon EOS 550D (Remodeled)
Location: Ooizumi, Hokuto city, Yamanashi pref.

Camera Settings: Recording Format...12bit CCD-RAW, converted to 16bit TIFF(5184×3456)
Sensitivity...ISO1600


IC4665 / Open Cluster, type c, III 2 m
R.A.17h 46m 18.0s (2000.0)
Dec.+05°43' 00" (2000.0)
Apparent Size41.0'
Real Size11.8 light yrs.
# of Stars30
Magnitude4.0
Distance990 light yrs.
IC4665 is a very sparse open cluster scattered at about a degree north of beta Oph. The cluster has a apparent diameter of about 40 arc minutes, you can enjoy that with a portable binocular. This IC4665 has only 30 member stars. Outward looks of the cluster would be almost same as the Milky Way flowing just next on east. But the cluster has a sufficient big size; we can take it only with small photo lenses easily.



NGC6940
IC4756, NGC6633

Copyright(c) 2019 by Naoyuki Kurita, All rights reserved.
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