scratch command

This page is part of the ING manual INS-DAS-29 Observation files for UltraDAS.


Scratch exposes the camera, reads it out and saves the data in a FITS file. The file is not passed to the archiving and logging facilities. A scratch file is identical to a file produced by run except that it has a different name and has the value "scratch" for the OBSTYPE keyword.

A title may be given for the observation: the title appears as the datum of the OBJECT keyword in the FITS headers.


   scratch [<camera>] <n> <exposure-time> ["<title>"]
where exposure-time is in seconds. The title-string must be enclosed in double quotes. Scratch file number n is used.

Notes and caveats:

Scratch files are ephemeral. If a scratch file of the given number exists, scratch overwrites it without warning.

It is not advisable to perform scratch exposures with the scratch number 1, as glance exposures create files, and will therefore overwrite any scratch file numbered 1.

Scratch files are produced in the current observation directory - the same one used for archiveable runs. The name of a scratch file is where n is the number of the file.

A scratch file may be made archiveable by the promote command, which will rename the scratch file with the next available run number, and thus make it available for archiving.