Da Plan

["Tom Droege" <droege@snapmail.us>]

In Chicago we have Da Bulls, Da Bears and Da Tass.  This is about Da Tass
plan for the coming season.

1) Take tiles.

We will take 4 x 4 degree tiles in the sky at the equator.  Above the
equator we will always take 4 degree in dec, but in ra they will enlarge
as we go towards the pole.  We will label the tiles with their integer ra,
dec.  We will produce .cal files representing an evenings run or part
thereof as we have done in the past, we will also generate a set of tile
files which will have file names including ra, dec and time.  We note that
the data looks much better, and really is better for the purpose of
finding variables when presented this way.

Tiles will overlap 0.2 degrees at the equator, at some declinations a lot
more.

2) Take 200 second exposures.

This should produce a few more stars than the previous runs.  We shall
see.  Certainly the mag 12 stars will be measured slightly better.  We
think the real value of this survey will be from mag 10 to 12.

3) Scan -6 to the pole

This requires 4 full time telescopes to get everything that croosses the
meridian.

4) Report in near real time.

We plan to take data in blocks of about 20 exposures.  This is enough to
make a good sky flat.  We can thus produce a fresh flat with every block
which might help to compensate for changing sky conditions.  We expect to
be able to put the .cal files on matt as they are reduced.  An hour or so
after the run ends.

5) One tom to track

We will set one of the telescopes to track the sky.  We can track for
about 3 hours.  This will produce a string of 36 or so exposures.  Almost
every set will have a new variable.  At least that is my experience so
far.  We will put these as they are recuced on matt.  Fair hunting.

6) Stop down the I telescopes.

I have not settled this for sure yet.  The I cameras see about twice the
sky background as the V cameras.  Stopping down to a 3 inch aperture makes
the sky background about equal.  I have tried this and the I focus is
clearly better.  Possibly I will cut masks at 3.5" and compromise.  Get a
little better focus and a reduced sky background.  Still testing.

Comments will be appreciated. It will be a month or two before this is
cast in stone.  Change is possible.  With this set up, we find lots of
variables in the range of mag 11-12.  A lot of them will be new.

tom1 is up and running.  tom2 should be running in a week.  We should have
all 5 systems running by August when the good season starts here.

Tom Droege

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