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desertstars
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Reged: 11/05/03
Posts: 34586
Loc: Tucson, AZ
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It eventually occurred to me to check the original source. In my copy of Collinder's original catalog he gives the RA/DEC coordinates for Cr 458 (and Harvard 21), that clearly place the object in Cassiopeia.
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Tom W.
Collinder's Catalog
Jewels in Dark Settings
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desertstars
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Reged: 11/05/03
Posts: 34586
Loc: Tucson, AZ
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While using the updated Collinder Catalog for a project of his own, CN member Al Whitney discovered a trio of errors involving coordinates. Object designations, constellations, and the CORRECT RA/DEC numbers follow:
Cr 328 (NGC 6352) Ara 17h 25m 29.1s -48° 25' 22"
Cr 391 (NGC 6705) Sct 18h 51m 05.9s -06° 16' 12"
Cr 418 (IC 4996) Cyg 20h 16m 31.7s +37° 38' 35"
In the interests of consistency, the corrections were taken from the NGC/IC Project and from Star Clusters by Brent Archinal and Steven Hynes.
Thank you Al for catching these and bringing them to my attention! 
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Tom W.
Collinder's Catalog
Jewels in Dark Settings
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Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2047
Loc: San Francisco, CA
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Tom,
Fantastic work.
I read the review and went through this Collinder Catalog a few weeks ago. From an astronomical/historical perspective, I'm quite fascinated by Per Collinder's classification system, i.e., generally Praesepe (M44) or Pleiades (M45). I suspect his classification was based upon, or uniquely derived from, commonly accepted views in astronomical observation and/or research of his period. What were those views? Why classify simply between M44 abd M45? It is just not self-evident to me.
I know the Trumpler classification system prevails today, but there are different evaluations of Praesepe and the Pleiades using this system.
At one website, I found the following, and I assume properly, referenced information:
Praesepe (M44):
I 2 r
II 2 m
II 2 r
Pleiades (M45):
II 3 r
I 3 r n
For reference, here's a link to that site for M45:
M45 Page
I use Cartes du Ciel frequently. I downloaded an interesting catalogue with the name Optically Visible Open Clusters (OVOC). The text files that come with the download are interesting. They indirectly provide a window upon the debates and differences among professional astronomers today. However, I assume the debates and differences of several decades ago are more difficult to research. It's remarkable that you were able to obtain Per Collinder's papers!
Clear Skies!
Todd
Edited by Man in a Tub (02/20/09 01:15 PM)
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desertstars
Please stand by...
Reged: 11/05/03
Posts: 34586
Loc: Tucson, AZ
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Quote:
I'm quite fascinated by Per Collinder's classification system, i.e., generally Praesepe (M44) or Pleiades (M45). I suspect his classification was based upon, or uniquely derived from, commonly accepted views in astronomical observation and/or research of his period. What were those views? Why classify simply between M44 abd M45? It is just not self-evident to me.
You might try digging up papers by his advisor, Knut Lundmark, to get a sense for how Collinder classified open clusters. My impression from the dissertation (which I've read just once, and that going on two years ago now) is that it was actually Lundmark's scheme, or one that he adapted.
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Tom W.
Collinder's Catalog
Jewels in Dark Settings
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Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2047
Loc: San Francisco, CA
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Thank you very much, Tom.
Sincerely,
Todd
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