3 Running Orac-dr

Once the environment has been configured the oracdr command will be available. Help on the available command line options can be listed by invoking oracdr -h. In its simplest form with no options, the pipeline will launch a logging window and start processing data from observation number 1 until no more data are available. For example³:

Note that the default setting is that Orac-dr will use the current UT date and start looking for observation number 1 in the ORAC_DATA_IN directory. It will wait for a flag file to appear until the timeout period expires (1 hour) or until the pipeline is aborted with CTRL-C. This behaviour is equivalent to running Orac-dr with the following options:

In many cases this is the correct behaviour at the telescope. In order to modify the behaviour of Orac-dr command-line options can be used.

3.1 Selecting a UT date

The UT date is required so that the names of the raw data files can be derived via observation numbers. The -ut option can be used to specify the UT date of interest. For example,

Currently, the pipeline can only process data from a single UT date in any single invocation. Data from multiple nights can not be coadded (even if they are in the same directory since the filename is derived from the UT)⁴.

In general, the oracdr_scuba can be used to configure the UT date so that the -ut flag will not be required. Rerun oracdr_scuba when data from a different UT date are to be reduced.

3.2 Choosing the observations

In many cases only a subset of the data in ORAC_DATA_IN are to be processed. Orac-dr provides a number of ways of specifying observations either as a range of observation numbers or as a list.

The options are:

-from

Specify the number of the first observation to be processed. This option defaults to ‘1’ if this option is omitted but the -to is present.

-to

Specify the number of the last observation to be processed. If the -from option is present but no -to option, then all the data will be processed starting from -from.

-list

Specify a list of observations. This list should be comma-separated. Colons can be used to indicate a range. For example, -list 1,2,3,5:10,15 would process observations 1,2,3,5,6,7,8,9,10 and 15.

-file

Specify a file containing names of files to be processed. This is useful for procesing data taken on different nights.

Here are some examples of selecting observations using Orac-dr:

Start at observation 5 and continue incrementing the observation number until no more files are available.

Start at observation 5 and finish at observation 20.

Start at observation 1 and finish at observation 20.

Process observations 1,2,3,4,5,20,21,22,23,24,25,30,31 and 32.

Process observations lists in textttmyfile.dat.

3.3 Looping schemes

There are a number of different ways of dealing with the data detection loop in Orac-dr. If the system is being used ‘off-line’, the data are all present in the input directory and the pipeline assumes that no new data will appear. In this case the list and inf detection loops are supplied which stop processing when data files can no longer be found. These are the default loops whenever observation numbers are specified with list being used in conjunction with the -list and -from/-to options and inf being used in conjunction with the -from option.

At the telescope new data are continually arriving so a different detection loop is required. The wait loop is used

Occasionally observation numbers are skipped (e.g. when an observation is aborted and not copied to the Sun). In this case the -skip option should be used. Without this option the data detection loop aborts when an observation can not be found (or it continues to wait for a file even though an observation with a higher number now exists). It is probably a good idea to always use the -skip option when processing SCUBA data.