Collinder 399 - The Coathanger

Collinder 399

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Location / Date

Zellerndorf, August 2018

Telescope / Mount / Guiding

ASA 10" Astrograph, ASA 3" Wynne-Corrector (focal length 910mm)
ASA DDM60, no Guiding

Camera / Exposure

Moravian G3-16200, Astrodon filters

2-panel mosaic:

Lum     25 x 10min, 24 x 10min
R         2 x (18 x 6min)
G         2 x (18 x 6min)
B         2 x (18 x 6min)

Total exposure time: 18h 58min


PixInsight, Fitswork, Photoshop


Collinder 399 (Cr 399) is a random grouping of stars located in the constellation Vulpecula. It is known as Al Sufi's Cluster or Brocchi's Cluster. The brighter members form an asterism also known as the Coathanger.

In 1931, Swedish astronomer Per Collinder listed it in his catalogue of open clusters. The group was considered to be a cluster for many years, but a study in 1970 concluded that only 6 of the brightest stars formed an actual cluster. Several independent studies since 1998 have now determined that this object is not a true cluster at all, but rather just a chance alignment of stars.

G055.0+01.8 is a small Planetary Nebula, discovered by F. Kerber, G. Lercher, W. Saurer, R. Seeberger and R. Weinberger (University Innsbruck) in 1994. His nature of a planetary nebula (PN) was proved by Kerber, Lercher and Weinberger in 1996, they named the PN KLW 3. L. Kohoutek included it in his "Catalogue of Galactic Planetary Nebulae" in 1996 and named the PN KLSS 1-2.

Sh2-83 is an emission nebula, it's size appears small, but its real dimensions and distance is unknown.

NGC 6802 and IC 1299 both are Open Clusters.

LBN 130 (DG 157) and GN 19.25.0 are very faint Reflection Nebulae.

This image was shortlisted in the Stars and Nebulae category of the Insight Investment Astronomy Photographer of the Year 2019.

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