[vsnet-sequence 137] The future of charts and sequences

["Mike Simonsen" <mikesimonsen@mindspring.com>]

Chart and sequence production is a thankless job, subject to criticism and
ridicule by experts and idiots alike.

U Gem is not the only example of a sequence that needs to be looked at and
revised or improved. There are several hundred stars that have very bad
AAVSO sequences and charts. AAVSO is well aware of this, and contrary to the
general consensus, is not reticent to change or improve their charts. I have
a list from HQ of over 400 stars prioritized for new, improved charts. The
problems with the existing sequence for U Gem are trivial compared to some
of the stars on this list.

Like any organization, AAVSO does not have unlimited resources or manpower
to attack this problem. For many years nearly all the responsibility of
chart production for AAVSO has fallen on Charles Scovil. He has done a
remarkable job, and continues to this day to produce charts that are part of
an extraordinary legacy in variable star astronomy. He now has some help
tackling the next generation of charts and sequences.

The decision has been made to finish a long list of charts for stars that
previously had no sequences or charts available first. Recently, charts
(standard and reversed) for 98 eclipsing binaries and 40 RR Lyr stars were
released. Soon there will be another 300 or so charts for CVs released with
CCD(V) photometry and color information tables. Revisions of some of the
older bad looking charts into the new computer generated format, and the
production of reverse charts is ongoing.

In the meantime, work progresses behind the scenes to reconcile the
differences between existing AAVSO, BAAVSS and RASNZ sequences. A small
group of determined and enthusiastic people are working out the parameters
and guidelines for creating a 'global sequence database'. The ultimate goal
being to have excellent sequences in a computer readable format that can be
downloaded by everyone, in the chart scale, orientation and limiting
magnitude of their choice. This information would also be available to sky
charting software vendors.

This group is not small because of exclusion. We have invited many, many
people to participate in the discussions and work. It is easy to complain
and point fingers. Few are actually willing to DO something about it.

It would be best if one sequence for each star could be used for all time by
all observers, especially in this age of freely exchanged information. The
data from all the various organizations would then be more compatible and
useful to astronomers everywhere.

As anyone who has tried to create a sequence from existing data knows, the
information available now to do so is not good. Yes, there is good
information available for bright stars. If you want to create a sequence
that only goes down to 10.5, existing information is pretty good. Fainter
than that, and serious problems arise. Nearly all the large surveys of stars
are more concerned with astrometry than photometry. Until there is an all
sky 'photometric' survey the only way to have accurate V sequences will be
through the efforts of individuals like Arne Henden, doing high quality
photometry for specific fields.

AAVSO has supplied CCDs and filters to interested individuals and
organizations to forward this cause, so they are at least putting their
money where their mouth is. They don't go around publicizing their concerns,
contributions and endeavors, even though I think they should, so I had to
say something about the beginnings of a line of AAVSO bashing on this
thread.

There is no point in doing revisions over and over again. It is expensive,
causes confusion and depletes resources unnecessarily. So some chart
revisions will have to wait until better photometry and information is
available, and the details and logistics of this fledgling effort to
globalize sequences has had some time to mature. But I don't think you will
have to wait as long as you might fear.

When I first started observing CVs, as the heart of my program I wanted to
observe all the stars in the BAAVSS Recurrent Objects Programme. I was
shocked to find that most of the existing charts for such a well established
program were either crap or non-existent. There are now world class
sequences from Henden/Sumner and soon to be AAVSO charts for nearly all the
stars on that list.

The internet has changed everything. We are now a real global community, and
we should act like it. Communication, cooperation, mutual respect and
freedom of expression will only benefit us as individuals, and as a whole,
in our exploration of the universe.

Mike Simonsen

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