Re: [APML] Last E-160 Photo!

["Paul M. Rybski" <rybskip@idcnet.com>]

Dear Jim,

      Your description of M45 includes a claim it contains O stars. 
This is not true:  the earliest spectral type in the cluster is B5, 
as can be found in any number of catalogs, from the Bright Star 
Catalog to Ruprecht and Alter's catalog of clusters and associations 
to Lynga's open cluster catalog.

      O stars simply do not last long enough for any cluster 
containing them to wander away from the molecular cloud which gave 
them birth.  Furthermore, were there any O stars remaining, whatever 
hydrogen were in the vicinity would ionize and the area would light 
up in the conventional red color of an H II region.

Paul

Paul Rybski, Physics, UW-Whitewater

>  Nice shot... flyboy! <g>
>
>      As an aside... it now seems that the reflection nebula involved in The
>Pleaides is pure chance... the cluster is 'flying through' the dust 
>cloud. This
>is based on studies of proper motion of the cloud and the cluster 
>individually.
>Sorry I can't quote you specific sources... just an article I 
>remember from one
>of the recent hobby magazines. If this has been absolutely confirmed, it might
>make an intresting addition to your text.    Again...
>
>  Nice M45...
>
>  Geoff Powers
>
>
>>  Well here's my last photo from the SE New Moon with the E-160! 
>>It's M45. Stack
>>  of (2) 45min exposures on Hyped PJ400. Itching for the OCT New 
>>Moon now!  It's
>>  the thumb in the upper right: M45-E160.
>  > http://flyboy999.freeyellow.com/Star%20Clusters/index2.htm
>>
>>
>>  Jim Ives
>>   http://flyboy999.freeyellow.com (Astrophotography)
>>  http://bwphotography.hypermart.net (Black and White Photography)
>>   flyboy9990@earthlink.net
>>
>>
>
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________________________________________
Paul M. Rybski, Ph.D.
Associate Professor and former Chair, Dept. of Physics, and
Director, Whitewater Observatory
Goodhue 320
University of WI-Whitewater
Whitewater, WI  53190-1790

Office FAX:     (262) 472-5633
Email address:  rybskip@uww.edu

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