|
|||
| Joint Astronomy Centre |
|
|
|
| Show document only |
Reducing ACSIS dataA quick guide - for all details see the Cookbook .DataJCMT heterodyne data obtained with ACSIS are written to disk and available at the JCMT or via CADC only as raw data. These files, with dimension frequency, position, time, such as a20070420_00014_01_0001.sdf are a time-stamped, receptor-position-stamped stream (of spectra), and as such are not 'cubes'. Multi subsystem files would have names a20070420_00014_01_0001.sdf, a20070420_00014_02_0001.sdf. At the JCMT raw data files are stored at /jcmtdata/raw/acsis/spectra/date, e.g. /jcmtdata/raw/acsis/spectra/20070420/00014/a20070420_00014_01_0001.sdf Raw data have to be regridded to cubes i.e. (Ra,Dec,frequency) using the command makecube of the package SMURF, or using ORACDR. At the JCMT the /home/jcmt* directories of observers often do not have enough place to store all reduced data. Observers can make subdirectories (mkdir) at /export/data/visitors to store large amounts of data.The released Starlink software can be a bit out of date compared to versions in Hilo/JCMT. For 32-bit and 64-bit Linux versions one can rsync with Hilo: 32-bit: mkdir star/ rsync -avz ssh.jach.hawaii.edu:/star/ star/64-bit: mkdir star/ rsync -avz ssh.jach.hawaii.edu:/net/malama/export/star64/ star/ HeadersHeader information can be checked with kappa fitslist a20070420_00014_01_0001.sdfThe positional information can be found with (add fullframe for even more info) kappa ndftrace a20070420_00014_01_0001.sdfother information in fits extensions can be accessed with hdstrace a20070420_00014_01_0001.sdfor in more detail for e.g. Trx with hdstrace a20070420_00014_01_0001.more.acsis.acsis.trx nlines=all Regridding ORACDRAt the JCMT data reduction with the ORACDR pipeline is usually started by the TSS. Data will be written to /jcmtdata/reduced/acsis/date Different products are made, apart from cubes, and baseline subtracted cubes (order 0), group files (e.g. ga20070420_14.sdf) which contain coadded data of the source first observed in scan 14. Observers can start ORACDR themselves: oracdr_acsis date setenv ORAC_DATA_OUT directory (for output data directory)Sometimes data files are large - at JCMT observers can use /export/data/visitors oracdr -h (gives help and options how to start) oracdr -skip -from 14 (will start at scan 14) Regridding SMURFIn some cases observers may want to regrid their data in a different way than ORACDR, or use options not yet available in ORACDR This can be done with the package SMURF using the command makecube, e.g.smurf makecube a20070420_00014_01_0001 outputfile autogridUse smurfhelp makecube parametersto find out all possibilities (most helpful are pixsize, autogrid, spread, specbounds). Data can be coadded, e.g. by making a text file with all filenames files.txt and then makecube in=^files.txt outputfileThe format of parameters is explained here. Looking to dataDatacubes can be visualised using GAIA (cubes; GAIA-3D) and SPLAT (single spectra) gaia filename splat filenameAlso in gaia one can send selected spectra to splat for further processing (rebinning, baselinefile, gaussfit, etc.) For manuals (gaia and splat, respectively) type showme sun214 showme sun243 One can also use separate KAPPA commands to process cubes and spectra. Some scripts (in /local/progs/bin) provide short-cuts. For help type sp_help(in Hilo and at JCMT). It is possible to convert data to CLASS format. Jan Wouterloot |