created: 03-03-2013.       revised: 06-16-2014.

In 1931, Swedish astronomer Per Collinder (1890 - 1974, born in Sundsvall, Sweden), created a catalog of the known galactic open star clusters as part of his graduate student thesis: “On structural properties of open galactic clusters and their spatial distribution”. His list contains 471 entries, of which a large number are already cataloged Messier and NGC objects. Most, of his work was based on using photographic plates taken from a variety of observatories,and Collinder actually observed very few of the objects himself. This graduate survey work of Collinder’s appears to be the highlight of his astronomical career, as he is more noted for his work in navigation.

Cr-399, the 'Coathanger'

The amateur astronomer will find many of his 'Cr' objects listed on star atlases and observing guides. While some of the 'Cr' objects are asterisms or even globular cluster, the majority of objects are open star clusters.
A fair number are unique objects, not listed in any other prior catalog. Visually, the Collinder catalog clusters cover a wide range, from naked-eye objects to those requiring binoculars or a small rich-field telescope, all the way up to needing a 20” or larger telescope. Collinder clusters can be found along the entire length of the Milky-Way, with the easiest to find being Cr399, the “Coathanger”, in Sagitta. Collinder clusters also cover a wide range in brightness, and can be found along sections of the Milky-Way, with several nice ones lying between Scutum, Sagittarius, and Scorpius.


Per Collinder classified his list into six unique sub-categories based on using three known star-clusters as class types, along with three additional general descriptive classes:

class Plei = Pleiades (M45)
class Praes = Prasepe (M44)
class u Norm = mu Normae (NGC6169)
class Glob = resembles a globular cluster
class Chain = resembles a asterism
class Neb = resembles a nebula or contains a nebula.

On the left side of the webpage is my personal observation list of the
'Collinder catalog of star clusters'.

I currently have observed all of the possible 348 objects visible from my Pittsburgh, PA latitude of around +40.
(123 of the 'Cr' objects are not observable from my location).

Hope you enjoyed the visit. Come again soon!
Larry McHenry,   Pittsburgh, PA. USA

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