[vsnet-chat 877] Re: Magnitudes, sequences, etc.

[aah@nofs.navy.mil (Arne A. Henden)]

  If Brian is correct, and you don't need better than 0.05mag accuracy
for the visual observer's charts, then you can be pretty sloppy and
still be ok.  Many professionals do not have ready access to a telescope,
instead having only a few nights allocated in 'observing runs', and
don't want to waste their time calibrating their data with standard
stars and extinction measures.  Even if they are willing to do so,
there is no guarantee of photometric weather during their runs.  This
may be why you don't see large quantities of sequences coming from
the professional ranks.
  Ready access to a telescope is one big advantage of an amateur
setup.  Another advantage is that you usually have only one CCD,
filter wheel, filter set and so have continuity of your measures.
Good filters are expensive, but not out of sight.  For example,
you can get quality filters from Custom Scientific in Tucson for
$150 per color, AR coated and mounted in cells for the SBIG filter
wheel.  For visual sequences, either B&V or V&R would be sufficient,
so you are talking $300 or so for filters.  I know many amateurs that
have gone this far in standardizing their systems.  Why not continue
along that path and learn how to do all-sky photometry?  Even from
Midwestern U.S. sites, you have 10-20percent of nights that are good
enough for such projects.  By providing standard sequences, you not
only help the visual observer, but also provide the necessary
calibration material for the professional.  But I'm preaching to
the choir here.
  We ended up publishing the list of 1600 FASTT variables in AJ at
considerable expense.  The only 'free' journals I know of are IBVS
and Monthly Notices.  I think at least distributing sequences through
a maillist like this is a start; home pages like what Brian is doing
for the sequences he finds/does that can be linked to are another
avenue.  Groups like VSNET and AAVSO keep their own databases as well,
so conventional 'publication' might not be necessary...just distribution.
Arne Henden

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