[vsnet-chat 878] Re: Magnitudes, sequences, etc

["William S G Walker" <astroman@voyager.co.nz>]

Greetings,

I have been aware of this problem for some time. In the last few days we
have received a couple of ST6Bs in Auckland (well I'm about 250km north of
that) and we will be making BVRI measures in certain fields which will
allow sequences to be determined. These will be available from the web page
(in the process of setting up) of the Photometry Section of the RASNZ. We
haven't made any earlier comments - except to Berto Monard - as we believe
in performance, not promises. 

The first of these should begin to be seen about the end of May. One small
problem is modifying the Bessell filters to fit the CCD camera but this
shouldn't be a great problem. Full calibration will be done, as usual with
anything from the Auckland Observatory, so the values should be good. The
limits are uncertain at the moment - the telescopes involved are a 25cm in
very dark skies, a 30cm in Auckland. But they should get down to v = 15 or
16.

On to some measures of V803 Cen!!

Regards,
Stan Walker
Director, Photometry Section, RASNZ


----------
> From: Bruce Sumner <b.sumner@bom.gov.au>
> To: vsnet-chat@kusastro.kyoto-u.ac.jp
> Cc: bas.lowell.edu@meteor3.ho.BoM.GOV.AU
> Subject: [vsnet-chat 868] Magnitudes, sequences, etc
> Date: Friday, May 01, 1998 4:50 AM
> 
> Thanks to Brian for the very insightful comments on photometry 
> (vsnet-chat 864). Why don't you guys (and girls) out there hear him? 
> I have been making CV charts now for over 20 years, and the hardest 
> part is getting a sequence. Unfortunately many people who should know 
> better are using GSC magnitudes as sequence stars. Don't fall into 
> that trap - they are garbage. And the USNO A1.0 catalogue, which 
> is extremely useful for the production of deep charts ( I use it 
> regularly), is useless for the final accurate magnitude sequence.
> 
> I understand there are some folks in the northern hemishere  
> currently testing the feasibility of producing CCD derived magnitude 
> sequnces for CV's.  The work of Arne Henden, Kent Honeycutt, and of 
> course, Brian Skiff, come to mind. Also Taichi Kato's VSNET charts 
> and sequences deserve mention. BUT these folk are ALL professional 
> astronomers . Where are you amateurs who could help. In particular is 
> there someone in the southern hemishere who would like to get 
> involved. You will gain the undying appreciation of fellow variable 
> star observers for your work.
> 
> There is so much concern and consternation out there about magnitudes 
> - why don't you get off your butts and do something about it? I 
> really hope Brian's comments get through - good charts and sequences, 
> properly published, are a thing of both beauty, usefulness and 
> timelessness. Who wants to get involved in some very beneficial CCD 
> sequence determinations?  
> 
> Bruce Sumner
> Melbourne
> =========================================
> 
> Bruce Sumner
> National Meteorological Operations Centre
> Bureau of Meteorology
> Australia
> 
> email:  b.sumner@bom.gov.au
> phone:  +613 9669 4349
> fax:    +613 9662 1223
> =========================================

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