Astro-Drawings 2001

by Gerhard Niklasch

Our Galaxy: Open Clusters

IC 4665, Open Cluster in Ophiuchus

IC 4665

Very large open cluster, really more of a binocular target than a telescopic one.

My logbook sketch underlying the XPaint drawing was made in order to identify the stars on another drawing by another artist: Nina Priebe. A day later, I looked at the cluster again whilst trying out my new 2" eyepiece holder (balancing the weight of a Paracorr and the rather bulky Wide Scan II), and suddenly I noticed that there are two groups of five stars each in a sort of skewed :.: arrangement, each with an arch of further stars attached to it, at right angles to each other and sharing a couple of stars! The southeastern group's baseline is on the right in the drawing, and the other two main stars close in on each other to the left of it. Its arch, pointing to the left, is the northwestern group's baseline. That group is upside down, its other two stars hanging down off the baseline and placed away from each other, with a little arch dangling down to the bottom left of the drawing.

The precise shapes of the two groups are fairly different, but my first attempts to match up Nina's drawing with photographs and published drawings (and Uranometria charts...) had been led astray because I was looking at the wrong one of the two!

The two groups are marked in orange on the second and third panel, respectively.

Drawn 2001 July 28, 02:35-02:45 MEST (00:35-00:45 UT), JD2452118.524

Instrument: 8" f/5 Newton, Panoptic 19mm (magnification c.52×)

G. Niklasch / Fri, 25 Jul 2003 16:25:40 MEST