udas_hct command

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


The header-collection task (HCT) mediates the collection of FITS-header packets from the ICS and TCS: it is a part of the central intelligence of the observing system (CIA) and runs on the system computer.

The HCT must be running when UltraDAS is asked to save observations.


   udas_hct <telescope> <instruments> &
where telescope is UltraDAS' formal name for the telescope (INT, JKT or WHT) and instruments is a list of instruments for which packets will be collected. In the most-common case, instruments is the formal name of a single instrument, e.g. IDS or WFC (case is significant). Where more than one instrument is active, instruments is a space-separated list of formal names enclosed in double quotes: e.g. "IDS WFC".

Notes and caveats:

The HCT is normally started by startobssys on the system computer. Observers should not normally have to invoke udas_hct directly.

The HCT inside UltraDAS is quite distinct from the HCT used with UltraDAS at the WHT: the former is a DRAMA programme running on the Unix system-computer and the latter is an ADAM programme running on the VMS instrument-computer. UltraDAS uses either one or the other, but not both at the same time. The udas_hct command applies to the HCT inside UltraDAS.

The HCT won't work properly if you run it on the DAS computer . (It will start up happily enough, but will find itself unable to talk to the ICS or TCS when you start taking data.) Always run it on the system computer .

There is no way to change the list of instruments served by the HCT once it is running. To add more instruments, shut it down and restart it.