Separate raw-data discs are used for each telescope. The discs are consistently named <tel><x> where <tel> is the telescope name, and x is a letter of the alphabet: e.g. whta, whtb, intf, etc..
The observing-log display lists all the data discs for the telescope,
showing the amount of space used and the amount of space free. However,
some of the discs shown may be allocated to reserve computers, or computers
of alternate systems, and these will not be available to you. Ask your
support astronomer or telescope operation which discs are live on your
/obsdata/intgInside each of these directories, you will find one directory for each night on which observations were written on that disc. The directory is named for the date of observation in the format yyyymmdd, e.g. 20000717 for 17th July 2000. The "night" is considered to start and end at 1200hrs UT, so that all observations from one night are stored in the same directory. The data in the directory name is the date on which the night started. For example,
/obsdata/intf/20000717would store all the observations from 1200hrs on 17th July until 1159hrs on 18th July.
Left to itself, UltraDAS will use the same data disc until it forced to change (due to that disc filling up or going off-line), or until you explicitly tell it to change. UltraDAS remembers which disc it was using for a particular detector from night to night, and across restarts of the control system; it will not change arbitrarily.
We recommend that review the choice of disc:
SYS> obsdataTo pick a specific disc yourself, add the name of the disc to the obsdata command, e.g.:
SYS> obsdata /obsdata/intg
If the disc is filled up during an observation by non-UltraDAS
software, there is a chance that UltraDAS will not be able to save the
observation and will lose it. For this reason, you should write reduced
data and similar files to a scratch disc, not to the raw-data disc.
This should never happen. The total disc space is always much grater than the data volume that can be acquired in one night, and old observations are erased from disc between nights as necessary. If space is short, ING staff may erase observation files older than 24 hours without warning. For this reason, you should always commit your data to tape (see below) within 24 hours of observation.
You should not yourself remove files form the raw-data discs without
checking with ING staff.
Inside the FITS file, there is a primary header describing the run as a whole, and one FITS image-extension per image. That is, simple, single-CCD cameras produce files containing a single image-extension, but CCD mosaics tend to produce files with one image-extension per CCD in the mosaic. If you window your detector, you will get one image-extension per readout window. When naming FITS-files to IRAF, you need to state the number of the extension as well: e.g.
CL> display /obsdata/intf/20000717/r1234567.fitto display the first image in run 1234567.
In normal operation, the data-manager will copy the observation files within 24 hours of the observation. You can check the on-line archive catalogue from the web pages of the ING intranet.
In due course, the CD-ROMs from the data manager are sent to the Astronomical
Data Centre at Cambridge, UK. The catalogue of observations is there made
available on the WWW. There is typically a delay of several months between
the observations being recorded and going on-line at Cambridge.
It is your responsibility as observer to make the tapes.