Deep Sky Object in Summer
Cr359 (Open Cluster in Ophiuchus)

Click on image to enlarge

Date & Time: Jun 27 2025, from 23:57 to 24:05 JST(+0900)
Composed 8 shots with 1 minute exposed
Optical: AF zoom-Nikkor 24-85mm (f=85mm, stop: F4.5)
with Kenko Starry-Night & Softon Clear filters
Auto-guided with EYEBELL CD-1 portable Equatorial
Digital Camera: Nikon D810A
Location: Furudono town, Fukushima pref.

Camera Settings: Recording Format...14bit CCD-RAW, converted to 16bit TIFF(7360×4912)
Device Size...FX format (36×24mm)
Sensitivity...ISO1600, White Balance...Daylight


Cr359 / Open Cluster, type IV 3 m
R.A.18h 01m 06.0s (2000.0)
Dec.+02°54' 00" (2000.0)
Apparent Size240.0'
Real Size55 light yrs.
# of Stars -
Magnitude3.0
Distance800 light yrs.
Other IDsMel 186
You can see a characteristic V-shaped asterism at about 4 degrees east of beta Ophiuchi. The stars has been classified as a sparse open cluster of Cr359. Our naked eyes can easily detect the cluster; a compact binocular is sufficient to enjoy it.
Once the open cluster formed the face of minor constellation of "Taurus Poniatovii". The constellation was named to honor Stanislaus Poniatowski, king of Poland and established in 1777. Presently the constellation has been abolished; the field is divided in territories of Ophiuchus, Serpens and Aquila.
This image has been cropped with an equivalent focal length 135mm.



IC4756, NGC6633
Cr399

Copyright(c) 2025 by Naoyuki Kurita, All rights reserved.
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