{"id":630,"date":"2014-11-26T10:45:55","date_gmt":"2014-11-26T20:45:55","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?page_id=630"},"modified":"2025-11-25T18:08:47","modified_gmt":"2025-11-26T04:08:47","slug":"reducing-acsis-data","status":"publish","type":"page","link":"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/data-reduction\/reducing-acsis-data\/","title":{"rendered":"Reducing ACSIS data"},"content":{"rendered":"<p>A quick guide &#8211; for all details see the <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20.html\"> Cookbook <\/a>.<\/p>\n<div id=\"toc_container\" class=\"no_bullets\"><p class=\"toc_title\">Contents<\/p><ul class=\"toc_list\"><li><a href=\"#Data\"><span class=\"toc_number toc_depth_1\">1<\/span> Data<\/a><\/li><li><a href=\"#Software\"><span class=\"toc_number toc_depth_1\">2<\/span> Software<\/a><\/li><li><a href=\"#Raw_Data\"><span class=\"toc_number toc_depth_1\">3<\/span> Raw Data<\/a><\/li><li><a href=\"#Quick_Reduction\"><span class=\"toc_number toc_depth_1\">4<\/span> Quick Reduction<\/a><\/li><li><a href=\"#Data_Products\"><span class=\"toc_number toc_depth_1\">5<\/span> Data Products<\/a><\/li><li><a href=\"#Visualising_Data\"><span class=\"toc_number toc_depth_1\">6<\/span> Visualising Data<\/a><\/li><li><a href=\"#Configuration_files\"><span class=\"toc_number toc_depth_1\">7<\/span> Configuration files<\/a><\/li><li><a href=\"#Polarization-separated_reduction_Namakanui_specific\"><span class=\"toc_number toc_depth_1\">8<\/span> Polarization-separated reduction (N\u0101makanui specific)<\/a><\/li><li><a href=\"#Combining_Images\"><span class=\"toc_number toc_depth_1\">9<\/span> Combining Images<\/a><\/li><li><a href=\"#Other_useful_commands\"><span class=\"toc_number toc_depth_1\">10<\/span> Other useful commands<\/a><ul><li><a href=\"#Namakanui_Receptors_8211_fitsheaders\"><span class=\"toc_number toc_depth_2\">10.1<\/span> N\u0101makanui Receptors &#8211; fitsheaders<\/a><\/li><\/ul><\/li><li><a href=\"#Conversion_to_CLASS_format\"><span class=\"toc_number toc_depth_1\">11<\/span> Conversion to CLASS format<\/a><\/li><\/ul><\/div>\n\n<h3><span id=\"Data\"><span id=\"Data\">Data<\/span><\/span><\/h3>\n<p>JCMT continuum data obtained with ACSIS are written to disk and available at the JCMT or via <a href=\"http:\/\/www.eaobservatory.org\/jcmt\/science\/archive\/\">CADC<\/a>.<\/p>\n<h3><span id=\"Software\"><span id=\"Software\">Software<\/span><\/span><\/h3>\n<p>For information on downloading and installing Starlink suite of data reduction and analysis software click <a href=\"http:\/\/www.eaobservatory.org\/jcmt\/observing\/getting-started\/#Starlink_analysis_and_reduction_software\">here<\/a>.<\/p>\n<h3><span id=\"Raw_Data\">Raw Data<\/span><\/h3>\n<p>Raw JCMT heterodyne data obtained with ACSIS data files follow a fixed naming convention. For instance, within the file name \u201c<em>a20070420_00014_01_0001.sdf<\/em>\u201c, the sub-sections have the following meaning:<\/p>\n<ol>\n<li>&#8220;a&#8221;: indicates data has been obtained by ACSIS.<\/li>\n<li>&#8220;20070420&#8221;: Indicates the UT date on which the observation was take.<\/li>\n<li>\u201c<em>00014\u2033:<\/em>\u00a0An index that uniquely identifies the observation within the night in question. So for instance, this file holds data for the 14th observation taken on\u00a0the 20th April 2007.<\/li>\n<li>&#8220;01&#8221;: instruments with two sidebands and\/or observations using multiple sub-systems this number identifies the sideband and\/or sub-system.<\/li>\n<li>\u201c<em>0001<\/em>\u201c: The sub scan index i.e. if the are too much data to fit into one raw file.<\/li>\n<li>\u201c<em>.sdf\u201d<\/em>: Indicates the file holds data in the STARLINK NDF format.<\/li>\n<\/ol>\n<p>* for <span id=\"Ala_8216ihi_86GHz_Squirrelfish\">`\u016a`\u016b, a <a href=\"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/dual-and-single-sideband\/\">2SB<\/a> instrument<\/span> you get a minimum of two files &#8211; one containing LSB data and another containing USB data. HARP is a <a href=\"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/dual-and-single-sideband\/\">SSB<\/a> instrument so there is only one sideband.<\/p>\n<h3><span id=\"Quick_Reduction\"><span id=\"Quick_Reduction\">Quick Reduction<\/span><\/span><\/h3>\n<p>To invoke the <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch9.html#x10-750009\">ORAC-DR<\/a> software:<\/p>\n<pre>oracdr_acsis<\/pre>\n<p style=\"text-align: justify\">This sets up ORAC-DR to run in your current working directory. You will also need to specify where your raw data is stored. For tcsh users we do:<\/p>\n<pre>setenv ORAC_DATA_IN folder\/<\/pre>\n<p>or for bash:<\/p>\n<pre>\u00a0export ORAC_DATA_IN=folder\/<\/pre>\n<p>For help with ORAC-DR simply do:<\/p>\n<pre>oracdr -help<\/pre>\n<p>To reduce your raw Heterodyne\u00a0 data using the ORAC-DR software run:<\/p>\n<pre>\u00a0oracdr -loop file -file mylist.lis<\/pre>\n<p style=\"text-align: justify\">where mylist.lis is a list of raw files (either for a specific wavelength, single\/multiple observations\/sub arrays) that should be located in the \u201cfolder\u201d directory as specified by ORAC_DATA_IN. the raw data will be automatically reduced using a per-defined reduction recipe.<\/p>\n<pre>oracdr -loop file -file mylist.lis -nodisplay -log sf\r\n<\/pre>\n<p>The above is another way of running the ORAC-DR pipeline. In the above example the output will be written to screen and logged in a .oracdr_* file (as specified by -log sf s = screen f = file) and not displayed in an xwindow (as specified -nodisplay).<\/p>\n<p>To really understand what is happening to your data it is advised to also (for the first few times\/reductions) run with -verbose. This will print messages from the Starlink engines (rather than just ORAC-DR messages):<\/p>\n<pre>oracdr -loop file -file mylist.lis -nodisplay -log sf -verbose<\/pre>\n<p style=\"text-align: justify\">If you have HARP data and one or two receptors are bad it is possible to exclude them (i.e H02 and H08 in this example) from a reduction by using a <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch6.html#x7-420004\">bad receptors<\/a> mask by running:<\/p>\n<pre>oracdr -loop file -file mylist.lis -nodisplay -log sf -verbose -calib bad_receptors=\\\"H02:H08\\\" \r\n<\/pre>\n<p>Please note sometimes this will mean you are required to update the default <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ap8.html#x20-111000H\">Quality Assurance parameters<\/a> as fewer pixels will remain in your map.<\/p>\n<p>&nbsp;<\/p>\n<h3><span id=\"Data_Products\"><span id=\"Data_Products\">Data Products<\/span><\/span><\/h3>\n<p style=\"text-align: justify\">Data that have been reduced by the pipeline have T<sub>sys<\/sub> and RMS for all receptors calculated, the pipeline also find and fits baselines, locates regions of emission using Clumpfind, creates moments maps, velocity maps and integrated intensity images. The <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch6.html#x7-440006\">output of the pipeline<\/a> includes the following:<\/p>\n<ol>\n<li>.oracdr_*.log &#8211; The ORAC-DR log file<\/li>\n<li>log.group \u2013 The files contributing to each group<\/li>\n<li>a20140103_00043_01_<strong>cube001<\/strong>.sdf &#8211; baselined cube<\/li>\n<li>a20140103_00043_01_<strong>integ<\/strong>.sdf &#8211; Integrated intensity image<\/li>\n<li>a20140103_00043_01_<strong>rimg<\/strong>*.sdf &#8211; Representative image (same as integ file), used to form rimg PNG<\/li>\n<li>a20140103_00043_01_<strong>sp001<\/strong>.sdf &#8211; Spectrum taken from position of peak intensity in the integ file<\/li>\n<li><span id=\"Visualising_Data\" dir=\"ltr\"><\/span>a20140103_00043_01_<strong>rsp<\/strong><em>*<\/em>.sdf &#8211; Representative spectrum (same as sp001), used to form rsp PNG<\/li>\n<li>a20140103_00043_01_<strong>iwc<\/strong>.sdf &#8211; Intensity weighted co-ordinate image<\/li>\n<li>a20140103_00043_01_<strong>noise<\/strong>.sdf &#8211; Noise map<\/li>\n<li>a20140103_00043_01_<strong>reduced001<\/strong>.sdf &#8211; Final trimmed,\u00a0baselined cube of the 1st (of n) file.<\/li>\n<li>a20140103_00043_01_<strong>rmslo<\/strong>.sdf &#8211; Low-frequency noise<\/li>\n<li>a20140103_00043_01_<strong>rmshi<\/strong>.sdf &#8211; High-frequency noise<\/li>\n<li>log.qa &#8211; Quality assurance reports<\/li>\n<li>log.noisestats &#8211; Noise statistics for each observation and group<\/li>\n<\/ol>\n<p style=\"text-align: justify\">Files beginning with prefix <em>a<\/em> are individual reductions of raw observations, the <em>a<\/em> simply identifies the data as being an ACSIS obervation. Files beginning\u00a0 with the prefix <em>ga<\/em> are coadded reductions of a number of observation (as determined by the files included in mylist.lis). The group files produced are as outlined above with the difference of the <em>ga<\/em> prefix and the omission of leading zero&#8217;s.<\/p>\n<ol>\n<li>ga20140103_43_1_<strong>reduced<\/strong>001.sdf &#8211; <em>Combined<\/em> baselined cube<\/li>\n<li>ga20140103_43_1_<strong>integ<\/strong>.sdf &#8211; <em>Combined<\/em> integrated intensity image<\/li>\n<\/ol>\n<p>For larger cubes the reduced file is split into several subcubes with the numbers 001, 002, &#8230;, which can be combined using the KAPPA command PASTE.<\/p>\n<pre>paste g*.sdf out=fullmap<\/pre>\n<p>or then they can be combined into a single co-added map with the <a href=\"http:\/\/starlink.eao.hawaii.edu\/docs\/sun265.htx\/sun265.html\">PICARD<\/a> recipe MOSAIC_JCMT_IMAGES:<\/p>\n<pre>picard -log sf MOSAIC_JCMT_IMAGES *files.sdf\r\n<\/pre>\n<h3><span id=\"Visualising_Data\"><span id=\"Visualising_Data\" dir=\"ltr\">Visualising Data<\/span><\/span><\/h3>\n<p>Images can be viewed using \u00a0<a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sun214.htx\/sun214.html\">GAIA<\/a>\u00a0(cubes; <a href=\"http:\/\/star-www.dur.ac.uk\/~pdraper\/gaia\/gaia3d\/index.html\">GAIA-3D<\/a>)\u2013 in interactive image and cube visualisation tool created by the STARLINK project for viewing NDFs and FITS files.<\/p>\n<pre>gaia ga20140103_00043_01_integ.sdf<\/pre>\n<p style=\"text-align: justify\">For greater versatility, the STARLINK <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sun95.htx\/sun95.html\">KAPPA<\/a> package contains many commands for visualising images in many different ways, including displaying multiple pictures in a grid, overlaying masks and contours, scatter plots, histograms, etc, etc.<\/p>\n<p style=\"text-align: justify\">Data can also be viewed in <a href=\"http:\/\/star-www.dur.ac.uk\/~pdraper\/splat\/index.html\">SPLAT<\/a> (single spectra):<\/p>\n<pre>splat a20140103_00043_01_sp001.sdf<\/pre>\n<h3><span id=\"Configuration_files\"><span id=\"Configuration_files\">Configuration files<\/span><\/span><\/h3>\n<p><a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch10.html#x11-820004\">ORAC-DR<\/a> is a pipeline that calls several STARLINK commands in order to reduce your data. the precise behavior of the pipeline is governed by the <em>recipe file<\/em>.\u00a0 You can find out which <em>recipe<\/em> is set in the data header via the FITS header RECIPE keyword in any of your raw files. For example both of these options will return the same result:<\/p>\n<pre>&gt;&gt; kappa\r\n\r\n&gt;&gt; fitsval ga20140103_43_1_reduced001.sdf RECIPE\r\n<br class=\"fancyvrb\" \/>&gt;&gt; fitslist ga20140103_43_1_reduced001.sdf |\u00a0grep\u00a0RECIPE\r\n<\/pre>\n<p>It is possible to run with a different recipe (i.e. REDUCE_SCIENCE_GRADIENT).\u00a0Links to specific reductions can be found in <span class=\"sectionToc\"><a id=\"QQ2-50-136\" href=\"http:\/\/starlink.eao.hawaii.edu\/docs\/sun260.htx\/sun260se11.html#x50-580004\">Appendix B \u2013 Main Recipes<\/a> and are executed by<\/span> entering the following:<\/p>\n<pre>&gt;&gt; oracdr -loop file -files myfiles.list REDUCE_SCIENCE_GRADIENT<\/pre>\n<p style=\"text-align: justify\">You can tailor the recipe parameters by supplying a .ini file (called myparams.ini in the following example). This file contains the recipe name (which must match the one assigned to your data, whether from the header or any different one specified on the command line) followed by the options you wish to specify in the following format:<\/p>\n<pre>[REDUCE_SCIENCE_NARROWLINE]<br class=\"fancyvrb\" \/>MOMENTS_LOWER_VELOCITY\u00a0=\u00a0-30.0<br class=\"fancyvrb\" \/>MOMENTS_UPPER_VELOCITY\u00a0=\u00a0155.0 <br class=\"fancyvrb\" \/>PIXEL_SCALE\u00a0=\u00a06.0,10.0<br class=\"fancyvrb\" \/>SPREAD_METHOD\u00a0=\u00a0gauss<br class=\"fancyvrb\" \/>SPREAD_WIDTH\u00a0=\u00a09<br class=\"fancyvrb\" \/>SPREAD_FWHM_OR_ZERO\u00a0=\u00a06<br class=\"fancyvrb\" \/>REBIN\u00a0=\u00a02<\/pre>\n<p>For more information about running ORAC-DR click <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch10.html#x11-820004\">here<\/a>.<\/p>\n<h3><span id=\"Polarization-separated_reduction_Namakanui_specific\"><span id=\"Combining_Images\">Polarization-separated reduction (N\u0101makanui specific)<\/span><\/span><\/h3>\n<p>The N\u0101makanui instruments produce data from both sidebands and polarizations. It is strongly recommended by the observatory that users check the data for each polarisation separately before combining them to use the total intensity spectra. To do this, you can make use of the <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc20.htx\/sc20ch6.html#x7-420004\">bad receptors<\/a> mask, running: \u00a0(instructions are for a bash-type shell)<\/p>\n<pre># Invoke the ORAC-DR software\r\noracdr_acsis\r\n\r\n# reduce only P0 data\r\nmkdir p0\r\nORAC_DATA_IN=$(pwd)\r\nORAC_DATA_OUT=$(pwd)\/p0\r\n# define P1 as \"bad receptor\" \r\n# in the line below, NU** is for Uu data, NW** is for Aweoweo, and NA** is for Alaihi;\r\necho \"NW1L NW1U NU1L NU1U NA1\" &gt;&gt; $ORAC_DATA_OUT\/bad_receptors.lis\r\n# call the reduction pipeline\r\noracdr -loop file -batch -file \"$ORAC_DATA_IN\"\/filelist.lis -nodisplay -log sf -verbose -calib bad_receptors=FILE\r\n<\/pre>\n<p>where the <em>filelist.lis<\/em>\u00a0is a text file containing raw data files to be reduced (see Section &#8220;Quick Reduction&#8221; above for details on this and the other parameters). Similarly, to reduce P1:<\/p>\n<pre># reduce only P1\r\nmkdir p1\r\nexport ORAC_DATA_IN=$(pwd)\r\nexport ORAC_DATA_OUT=$(pwd)\/p1\r\n# define P0 as \"bad receptor\"\r\n# in the line below, NU** is for Uu data, NW** is for Aweoweo, and NA** is for Alaihi; \r\necho \"NW0L NW0U NU0L NU0L NA0\" &gt;&gt; $ORAC_DATA_OUT\/bad_receptors.lis\r\n# call the reduction pipeline\r\noracdr -loop file -batch -file \"$ORAC_DATA_IN\"\/filelist.lis -nodisplay -log sf -verbose -calib bad_receptors=FILE\r\n<\/pre>\n<p>and you will find your spectra in P0-only and P1-only under the folders <em>p0\/<\/em> and <em>p1\/<\/em>, respectively. Note, for the receptors, N stands for N\u0101makanui, the next letter is either A for Alaihi, U for \u02bb\u016a\u02bb\u016b or W for \u02bb\u0100weoweo. The number corresponds to polarization 0 or 1, and the final letter is L or U for Lower or Upper sideband.<\/p>\n<p><strong>Important note:<\/strong> These instructions to reduce each polarisation separately will not work for standard calibrator sources. ORAC-DR assigns the reduction recipe &#8220;REDUCE_STANDARD&#8221; to any observation with a &#8216;standard&#8217; flag in it (i.e., standard calibrators). The REDUCE_STANDARD recipe, by default, ignores the &#8220;bad_recptors&#8221; file supplied to ORAC-DR. The way to fix this is to specify the recipe as &#8220;REDUCE_SCIENCE_NARROWLINE&#8221; when running the reduction as follows:<\/p>\n<pre><code>oracdr -loop file -batch -file \"$ORAC_DATA_IN\"\/filelist.lis -nodisplay -log sf -verbose -calib bad_receptors=FILE REDUCE_SCIENCE_NARROWLINE<\/code><\/pre>\n<p>If you want to produce the polarization-combined spectra simply remove the parameter &#8220;-calib bad_receptors=FILE&#8221;:<\/p>\n<pre># reduce both pols combined\r\nmkdir combined\r\nexport ORAC_DATA_IN=$(pwd)\r\nexport ORAC_DATA_OUT=$(pwd)\/combined\r\noracdr -loop file -batch -file \"$ORAC_DATA_IN\"\/filelist.lis -nodisplay -log sf -verbose\r\n<\/pre>\n<p>and you will obtain the spectra with both polarizations combined inside the <em>combined\/<\/em> folder.<\/p>\n<h3><span id=\"Combining_Images\"><span id=\"Combining_Images\">Combining Images<\/span><\/span><\/h3>\n<p>If you have reduced several Heterodyne files that you wish to combine into a single co-added map, this can be done with the <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sun265.htx\/sun265.html\">PICARD<\/a> recipe MOSAIC_JCMT_IMAGES:<\/p>\n<pre>picard -recpars mypar.lis MOSAIC_JCMT_IMAGES *files.sdf\r\n<\/pre>\n<p>where the \u201cparameter file\u201d <em>mypar.lis<\/em>\u00a0looks like the following, with a mosaic method specified (in this example <em>makemos<\/em>):<\/p>\n<pre>[MOSAIC_JCMT_IMAGES]\r\nMOSAIC_TASK = makemos\r\nMAKEMOS_METHOD = mean\r\n<\/pre>\n<h3><span id=\"Other_useful_commands\"><span id=\"Other_useful_commands\">Other useful commands<\/span><\/span><\/h3>\n<p>Header information can be checked with<\/p>\n<pre>kappa\r\nfitslist a20070420_00014_01_0001.sdf<\/pre>\n<p>Fitslist is a powerful tool and with it you can check part<span style=\"font-size: 12pt\">icular attributes:<\/span><span style=\"font-size: small\"><span style=\"font-size: 12pt\"> Dates of observations<\/span><\/span><\/p>\n<pre>fitslist file | grep DATE-OBS\r\nfitslist file | grep DATE-END<\/pre>\n<p>Observing conditions:<\/p>\n<pre>fitslist file | grep TAU225ST TAU225EN\r\nfitslist file | grep WVMTAUST WVMTAUEN<\/pre>\n<p>System temperatures:<\/p>\n<pre>smurf\r\ngettsys -statistics myfile #This command works for raw data only.\r\nhdstrace a20090718_00024_01_0001.more.tsys nlines=all\r\nfitslist file | grep MEDTSYS<\/pre>\n<p>Tracking receptor (HARP only):<\/p>\n<pre>fitslist file | grep INSTAP<\/pre>\n<p>Observing mode<\/p>\n<pre>fitslist file | grep SAM_MODE\r\nfitslist file | grep SW_MODE\r\nfitslist file | grep CHOP_FRQ CHOP_PA CHOP_THR<\/pre>\n<p>Bandwidth and resolution<\/p>\n<pre>fitslist file | grep BWMODE\r\nfitslist file | grep SUBBANDS\r\nfitslist file | grep NCHNSUBS<\/pre>\n<p>reference position<\/p>\n<pre>fitslist file | grep SKYREFX\r\nfitslist file | grep SKYREFY<\/pre>\n<p>Instrument calibration<\/p>\n<pre>fitslist file | grep SW_MODE\r\nfitslist file | grep CHOP_FRQ CHOP_PA CHOP_THR<\/pre>\n<p>Integration time<\/p>\n<pre>fitslist file | grep INT_TIME<\/pre>\n<p>Reduction history<\/p>\n<pre>hislist out<\/pre>\n<p>Backend<\/p>\n<pre>fitslist file | grep BACKEND<\/pre>\n<p style=\"text-align: justify\">The positional information can be found with (add fullframe for even more info) ndftrace which displays the attributes of the data structure. This will tell you the units of the data, pixel bounds, dimensions and axis assignations.<\/p>\n<pre>kappa\r\nndftrace a20070420_00014_01_0001.sdf\r\nndftrace file fullframe fullwcs<\/pre>\n<p>other information in fits extensions can be accessed with<\/p>\n<pre>hdstrace a20070420_00014_01_0001.sdf<\/pre>\n<p>or in more detail for e.g. T<sub>rx<\/sub> with<\/p>\n<pre>hdstrace a20070420_00014_01_0001.more.acsis.trx nlines=all<\/pre>\n<p>Files contributing to a coadd can be examined via:<\/p>\n<pre>provshow out<\/pre>\n<h4><span id=\"Namakanui_Receptors_8211_fitsheaders\">N\u0101makanui Receptors &#8211; fitsheaders<\/span><\/h4>\n<p>To look at what receptors were working at the time &#8211; a particualrly useful trick for `\u016a`\u016b or \u02bb\u0100weoweo, one can use fitsval or fitslist to look at the specific fitsheader &#8220;RECPTORS&#8221; (not a typo) e.g. All examples given below are for \u02bb\u016a\u02bb\u016b &#8211; Note that for \u02bb\u0100weoweo, NU*L and NU*U -&gt; NW*L and NW*U (N stands for N\u0101makanui, the next letter is either U for \u02bb\u016a\u02bb\u016b or W for \u02bb\u0100weoweo. The number corresponds to polarization 0 or 1, and the final letter is L or U for Lower or Upper sideband.)<\/p>\n<pre>fitslist a20201203_00124_01_0001.sdf | grep RECPTORS<\/pre>\n<pre>RECPTORS= 'NU0L NU0U NU1L NU1U ' \/ Active FE receptor IDs for this observation<\/pre>\n<p>or by using fitsval e.g.<\/p>\n<pre>fitsval a20201203_00124_01_0001.sdf RECPTORS<\/pre>\n<pre>NU0L NU0U NU1L NU1U<\/pre>\n<p>and also look at fitsheaders OBS_SB and TRACK_SB e.g.<\/p>\n<pre>OBS_SB\t= 'USB\t   '\t       \/ The observed sideband (this subsystem)\r\nTRACK_SB= 'USB\t   '\t       \/ The tracking sideband (primary subsystem)<\/pre>\n<p>after a reduction has been made one can look for the fitsheader RECPUSED to find out what receptors are in the reduced file:<\/p>\n<pre>RECPUSED= 'NU1U NU0U'\t       \/ Used receptor IDs\r\n\r\n<\/pre>\n<h3><span id=\"Conversion_to_CLASS_format\">Conversion to CLASS format<\/span><\/h3>\n<p>It is possible to convert the spectra to CLASS format, or the cubes to GDF files, readable by the IRAM GILDAS software package, see <a href=\"http:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/data-reduction\/reducing-acsis-data\/converting-to-class-format\/\">here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A quick guide &#8211; for all details see the Cookbook . Data JCMT continuum data obtained with ACSIS are written to disk and available at the JCMT or via CADC. Software For information on downloading and installing Starlink suite of data reduction and analysis software click here. Raw Data Raw\u2026 <a class=\"continue-reading-link\" href=\"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/data-reduction\/reducing-acsis-data\/\">Continue reading<\/a><\/p>\n","protected":false},"author":10,"featured_media":0,"parent":172,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/630"}],"collection":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/comments?post=630"}],"version-history":[{"count":78,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/630\/revisions"}],"predecessor-version":[{"id":13432,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/630\/revisions\/13432"}],"up":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/172"}],"wp:attachment":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/media?parent=630"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}