(meteorobs) Re: Is Sirius Getting Dimmer, or Moving Closer to Us?

To: meteorobs@atmob.org
Subject: (meteorobs) Re: Is Sirius Getting Dimmer, or Moving Closer to Us?
From: Robert Lunsford <lunro.imo.usa@coxdot net>
Date: Tue, 26 Nov 2002 14:16:21 -0800
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Mark and All,

Sirius is not getting dimmer. It's our ability to obtain precise 
magnitudes and distances that is getting better. My advice would be to 
use the latest available figures for these parameters.

Clear Skies!

Bob Lunsford


Mark Fox wrote:
> November 24, 2002
> 
> Greetings Meteor Enthusiasts!
> 
> Although a starry topic may seem slightly "O.T.," I
> think stars are so entwined with meteor observing that
> they make up a necessary aspect of meteor science
> rather than an unrelated subject matter set aside for
> star gazers and trained telescopes.  If the latter 
> were so, picture how difficult meteor hunting would be
> if observers ignored the use of stars!
> 
> With that said, I have a starry question.  In one of 
> my old star books (a Golden Nature Guide, copyrighted
> 1951) lists the bright star Sirius with a visual
> magnitude of -1.58.  In the Encyclopedia Britannica
> (1969) they list it as -1.45 mag.  However, on the
> Heavens Above web site (which I frequently visit) the
> star is now listed as -1.44 mag.  Now Sirius, being a
> relatively close star, may cause someone to conclude
> that the differences in magnitude result from the
> actual movement of the star--- that is, Sirius has
> noticeably moved away in the past 50 or so years. 
> However, this may not be so if its differences in
> distance are correct.  In the Encyclopedia Britannica 
> a distance of 8.70 lightyears is given while on the
> Heavens Above web site a value of 8.60 is present. 
>>From this, the star is obviously moving closer.  
> 
> Are these inconsistencies the result of past errors
> and/or uncertainties, as perhaps suggested by 
> the information given on the Heavens Above web site?  
> 
> Thank you all in advance for any clarifications or
> help.
> 
> Long, glowing, and stony Geminids!
> 
> Mark Fox
> Newaygo, MI USA
> Coordinates: 43 deg. 27' N, 85 deg. 49' W

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(meteorobs) Is Sirius Getting Dimmer, or Moving Closer to Us?

From: Mark Fox <unclefireballmtf@yahoo.com>