[vsnet-chat 875] Re: Magnitudes, sequences, etc

[Taichi Kato <tkato>]

Brian Skiff wrote:

>      Well, if Kiyota-san is getting results but not distributing them, then
> how will we know about them, use them, or even know what objects still need
> work?

   Even myself don't know what fields he has already worked with.  I usually
know some of his work through Japanese astronomical magazines, in which he
regularly writes an article.  Just remind, this is an example.  There must
be at least tens of people who are doing the similar job, but why we don't
see the results?  There must be an obstacle (unseen by well-experienced
professionals?).

> If he and others are hesitant about publishing possibly erroneous
> results, then I'm sure there are enough experienced photometrists associated
> with VSNET in various countries who would be willing to check things. Before
> long the amateur observers will become experts themselvesand will know from
> their reductions which of their results are reliable and to what level.

   I hope so, it looks too optimistic whether the art of photometry widely
prevails.  The situation looks different from astrometry.  Astrometric
accuracy is rather easily assessed using O-C's from published orbital elements,
while in photometry one must usually assure self-assessment.  This process
is difficult even for professional astronomers.  Moreover, astrometry is
not usually affected by the passband, while photometry involves a high degree
of complexity in color systems.  The process involved in the latter
transformation seems to me largely discouraging (not so highly photometry-
inclined) observers.  The degree of freedom in aperture photometry parameters
is also perplexing.

   I also look forward to hearing from amateurs seriously interested in
this kind of calibrating works.

>      As an aside to any students or professionals who might be reading this
> that are involved with supernova (or other) photometry:  even just one or two
> nights of calibrated photometry on even a couple of stars in a field of
> interest is sufficient for most purposes.  The Ouda group (for instance) can
> use those few stars to set zero-points for the rest of the field working
> differnetially from your data.

   I wonder why professionals following these targets, and probably defining
their local comparison stars, don't usually make preliminary results on
local comparison stars publicly available.  I have, via VSNET or privately,
received only few such estimates.  Considering other groups doing far more
abundant observations (appearing on journals, often years later) on far more
photometric nights than Ouda, it's quite a mystery.

>    Besides distribution over VSNET, there's a perfect vehicle for publishing
> the sequences done by amateurs, which is the IBVS.  These are published
> rapidly, are free of page charges, and are indexed by SIMBAD, so the 
> information in them receives wide circulation.  Importantly also, they are
> available via the Web, so one does not even need to subscribe in order to
> read them.  Many amateurs already publish regularly in IBVS.

   Well, the IBVS is still a hard target for amateurs, at least not regarded
very convenient.  I understand the publishing policy of the IBVS has become
more inclined to stellar (and binary) physical parameters.  While photometry
of non-variable stars providing some basic stellar physical parameters,
this field looks slightly off-topic from what the IBVS becomes focusing.
I remember a comment at the IAU Commision on Variable Stars that reports on
individual variable star discovery are no longer necessary; monthly
announcements will suffice.  Although this comments received arguments
against, it was enough to convince myself that the circumstances around the
IBVS is definitely changing.

Regards,
Taichi Kato

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