[Date Prev][Date Next][Thread Prev][Thread Next][Search] [Main Index] [Thread Index] [HEASARC Mailing List Archives]

schedules and ephemeris in FITS


I'm interested in improving communications between EUVE Guest
Investigators and CEA on spacecraft scheduling issues.  In particular,
I'm interested in finding out about FITS binary table formats that
have been defined (or used) to transmit data about ephemeris.  Also,
has anyone worked on representing scheduling information -- ie, when a
target is visible, when star trackers are operable, etc.

For the ephemeris, I'm looking for a relative simple file containing
say 3 columns: time, ra, dec (including appropriate header information
about coordinate systems, units, etc).  It would be nice to have a 4th
column with the radial distance.  For example, in scheduling Moon
observations, EUVE must account for the relative position of the Moon
to the spacecraft.  Has anybody come across this type of FITS table?

I think that the scheduling information is more complex.  The basic
information in our scheduling system is "run-length encode" --
intervals of time are suitable (or not).  In practice, however, these
time intervals are actually all the same size.  Additionally, the
suitability of the observation during the time interval has a metric
that runs from 0 (not suitable) to 1 (most suitable).  I'm not sure
how common this system is for other spacecraft scheduling systems.

For all the suitable time intervals, we would like to maintain a list
of all the roll angles that are valid to use for the duration of the
time interval.  Additionally, for all non-suitable time intervals, we
would like to know which pointing constraint was violated.

I'd appreciate any information on either of these issues, or other
systems that are related to these problems.

Thanks in advance,