{"id":2915,"date":"2015-05-13T11:37:59","date_gmt":"2015-05-13T21:37:59","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?page_id=2915"},"modified":"2019-03-19T14:35:52","modified_gmt":"2019-03-20T00:35:52","slug":"calibrators","status":"publish","type":"page","link":"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/continuum\/scuba-2\/calibration\/calibrators\/","title":{"rendered":"SCUBA-2 Calibrators"},"content":{"rendered":"<p style=\"text-align: justify\"><div id=\"toc_container\" class=\"no_bullets\"><p class=\"toc_title\">Contents<\/p><ul class=\"toc_list\"><li><a href=\"#Primary_Calibrators\"><span class=\"toc_number toc_depth_1\">1<\/span> Primary Calibrators<\/a><ul><li><ul><li><a href=\"#Fluxes\"><span class=\"toc_number toc_depth_3\">1.0.1<\/span> Fluxes<\/a><\/li><\/ul><\/li><\/ul><\/li><li><a href=\"#Secondary_Calibrators\"><span class=\"toc_number toc_depth_1\">2<\/span> Secondary Calibrators<\/a><\/li><li><a href=\"#SCUBA_Calibration\"><span class=\"toc_number toc_depth_1\">3<\/span> SCUBA Calibration<\/a><ul><li><a href=\"#Primary_Calibrators-2\"><span class=\"toc_number toc_depth_2\">3.1<\/span> Primary Calibrators<\/a><\/li><li><a href=\"#Secondary_Calibrators-2\"><span class=\"toc_number toc_depth_2\">3.2<\/span> Secondary Calibrators<\/a><\/li><\/ul><\/li><\/ul><\/div>\n\n<h2><span id=\"Primary_Calibrators\">Primary Calibrators<\/span><\/h2>\n<p>Uranus and Mars are used as the primary calibrators for SCUBA-2. Calibrators for SCUBA-2 are observed with a DAISY pattern which is optimised for point-like and compact sources. When determining the standard FCF numbers the data were reduced using the SMURF routine <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc21.htx\/sc21.html\"> <span style=\"color: blue\">makemap<\/span><\/a>. The total flux for each calibrator was determined using a 60 arcsec diameter aperture, with the background level calculated between the diameters 90-120 arcsecs.<\/p>\n<p>For further details, including a description of the derivation of the FCF, see <a href=\"http:\/\/cdsads.u-strasbg.fr\/abs\/2013MNRAS.430.2534D\">Dempsey et al. MNRAS, 2013<\/a>.<br \/>\nFor instructions on applying the FCF see the <a href=\"http:\/\/starlink.eao.hawaii.edu\/devdocs\/sc21.htx\/sc21.html\">SCUBA-2 data reduction cookbook (HTML)<\/a>, also available as a <a href=\"http:\/\/www.starlink.ac.uk\/devdocs\/sc21.pdf\">PDF version<\/a>.<\/p>\n<h4><span id=\"Fluxes\">Fluxes<\/span><\/h4>\n<p><a href=\"http:\/\/starlink.eao.hawaii.edu\/starlink\"> Starlink<\/a> supplies a command line program <a href=\"http:\/\/starlink.eao.hawaii.edu\/docs\/sun213.htx\/sun213.html\">FLUXES<\/a> which can return the expected flux for each planet for any date specified. Several options are available including writing the data to a file, and returning the values today. Alternatively if you are at the telescope you can use the FLUXNOW program which defaults to the current date and time.<\/p>\n<h2><span id=\"Secondary_Calibrators\">Secondary Calibrators<\/span><\/h2>\n<table border=\"\">\n<tbody>\n<tr>\n<th rowspan=\"2\" align=\"center\">Source<\/th>\n<th rowspan=\"2\" align=\"center\">R.A.<\/th>\n<th rowspan=\"2\" align=\"center\">Dec.<\/th>\n<th colspan=\"2\" align=\"center\">850 \u00b5m<\/th>\n<th colspan=\"2\" align=\"center\">450 \u00b5m<\/th>\n<\/tr>\n<tr>\n<th><span style=\"font-size: small\">\u00a0 Peak flux (Jy\/beam)\u00a0<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0 Integ. flux (Jy)\u00a0<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0 Peak flux (Jy\/beam)\u00a0<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0 Integ. flux (Jy)\u00a0<\/span><\/th>\n<\/tr>\n<tr>\n<td align=\"center\">CRL 618<\/td>\n<td align=\"center\">04:42:53.67<\/td>\n<td align=\"center\">+36:06:53.17<\/td>\n<td align=\"center\">4.89 \u00b1 0.24<\/td>\n<td align=\"center\">5.0 \u00b1 0.2<\/td>\n<td align=\"center\">11.5 \u00b1 1.4<\/td>\n<td align=\"center\">12.1 \u00b1 1.05<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">CRL 2688<\/td>\n<td align=\"center\">21:02:18.27<\/td>\n<td align=\"center\">+36:41:37.00<\/td>\n<td align=\"center\">5.64 \u00b1 0.27<\/td>\n<td align=\"center\">6.13 \u00b1 0.2<\/td>\n<td align=\"center\">24.9 \u00b1 2.9<\/td>\n<td align=\"center\">29.1 \u00b1 2.5<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">Arp 220<\/td>\n<td align=\"center\">15:34:57.27<\/td>\n<td align=\"center\">+23:30:10.48<\/td>\n<td align=\"center\">0.79 \u00b1 0.09<\/td>\n<td align=\"center\">0.81 \u00b1 0.07<\/td>\n<td align=\"center\">5.2 \u00b1 0.8<\/td>\n<td align=\"center\">5.4 \u00b1 0.7<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">HD 169142<\/td>\n<td align=\"center\">18:24:29.78<\/td>\n<td align=\"center\">-29:46:49.37<\/td>\n<td align=\"center\">0.52 \u00b1 0.03<\/td>\n<td align=\"center\">0.58 \u00b1 0.02<\/td>\n<td align=\"center\">2.21 \u00b1 0.25<\/td>\n<td align=\"center\">2.78 \u00b1 0.24<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">HD 135344B<\/td>\n<td align=\"center\">15:15:48.44<\/td>\n<td align=\"center\">-37:09:16.02<\/td>\n<td align=\"center\">0.46 \u00b1 0.03<\/td>\n<td align=\"center\">0.53 \u00b1 0.02<\/td>\n<td align=\"center\">1.66 \u00b1 0.27<\/td>\n<td align=\"center\">3.30 \u00b1 0.34<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">MWC 349<\/td>\n<td align=\"center\">20:32:45.53<\/td>\n<td align=\"center\">40:39:36.6<\/td>\n<td align=\"center\">2.21 \u00b1 0.11<\/td>\n<td align=\"center\">2.19 \u00b1 0.08<\/td>\n<td align=\"center\">3.4 \u00b1 0.26<\/td>\n<td align=\"center\">3.2 \u00b1 0.25<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">V883 Ori<\/td>\n<td align=\"center\">05:38:19<\/td>\n<td align=\"center\">-07:02:22<\/td>\n<td align=\"center\">1.55 \u00b1 0.09<\/td>\n<td align=\"center\">2.0 \u00b1 0.07<\/td>\n<td align=\"center\">7.8 \u00b1 1.0<\/td>\n<td align=\"center\">11.0 \u00b1 0.94<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">HL Tau<\/td>\n<td align=\"center\">04:31:38.44<\/td>\n<td align=\"center\">+18:13:57.65<\/td>\n<td align=\"center\">2.32 \u00b1 0.01<\/td>\n<td align=\"center\">2.42 \u00b1 0.08<\/td>\n<td align=\"center\">8.3 \u00b1 1.03<\/td>\n<td align=\"center\">10.3 \u00b1 0.86<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>For full details see <a href=\"http:\/\/cdsads.u-strasbg.fr\/abs\/2013MNRAS.430.2534D\">Dempsey et al. (2013)<\/a>.<\/p>\n<hr \/>\n<p>For historical reference, the calibration information for the original SCUBA can be found here.<\/p>\n<p><strong><h2 class=\"collapseomatic \" id=\"id69d8df7fe1c73\"  tabindex=\"0\" title=\"SCUBA Calibration\"    ><span id=\"SCUBA_Calibration\">SCUBA Calibration<\/span><\/h2><div id=\"target-id69d8df7fe1c73\" class=\"collapseomatic_content \"><\/strong><\/p>\n<h3><span id=\"Primary_Calibrators-2\">Primary Calibrators<\/span><\/h3>\n<p>The primary sources used for calibration of SCUBA data are the planets Mars, Uranus and Neptune. The brightness of these sources varies with time &#8211; as the spatial separation between the Earth and each planet varies. In addition the brightness of Mars varies depending on the orientation of the planet with respect to both the Earth and the Sun.<\/p>\n<h3><span id=\"Secondary_Calibrators-2\">Secondary Calibrators<\/span><\/h3>\n<p>For SCUBA data we point you to the <a href=\"http:\/\/star-www.rl.ac.uk\/docs\/sc11.htx\/sc11.html\">SCUBA Data Reduction Cookbook<\/a>, which contains a quick guide as well as further advice. <\/p>\n<p>The primary flux calibration of SCUBA data is based on the planets Mars, Uranus and Neptune, but at some times of the night and year these may be unavailable. A (very) small set of &#8216;secondary&#8217; calibrators has been collated from a variety of sources to use during these times, but these are few and far between and most of them are not ideal!<\/p>\n<p>The values below were obtained for a new analysis of observations between April 1st 2000 and September 30th 2003, with the exception of the variable calibrators OH 231.8 and IRC+10216, for which the complete data sets have been used from 1997 &#8211; 2003. The values are all in agreement with our previous values, derived from (usually fewer) observations between 1997 and 2001. Wherever possible, only observations with 120&#8243; chop throws have been used in this analysis. For the variable calibrators, use the links in the table below to see the updated curves.<\/p>\n<p>For each source, two flux estimates are given at each wavelength. The first is the peak flux, in Jy\/beam, which can be used for unresolved sources and also for photometry observations (see this <a href=\"http:\/\/docs.eao.hawaii.edu\/JACdocs\/JCMT\/SCD\/SN\/004\/photom_analysis.html#scuphot\">note<\/a> for guidance). The second is the integrated flux within a circular aperture with 20&#8243; radius, in Jy\/aperture, which should be used for resolved sources (see this <a href=\"http:\/\/xxx.lanl.gov\/abs\/astro-ph\/0204428\"> paper<\/a> by Jenness et al. for a more in-depth discussion on this issue).<\/p>\n<p>&nbsp;<\/p>\n<table border=\"\">\n<tbody>\n<tr>\n<th rowspan=\"2\" align=\"center\">\u00a0 Calibrator<\/th>\n<th rowspan=\"2\" align=\"center\">R.A.<\/th>\n<th rowspan=\"2\" align=\"center\">Dec.<\/th>\n<th colspan=\"2\" align=\"center\">850 \u00b5m<\/th>\n<th colspan=\"2\" align=\"center\">450 \u00b5m<\/th>\n<\/tr>\n<tr>\n<th><span style=\"font-size: small\">\u00a0Peak flux (Jy\/beam)<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0Integ. flux (Jy\/aper.)<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0Peak flux (Jy\/beam)<\/span><\/th>\n<th><span style=\"font-size: small\">\u00a0Integ. flux (Jy\/aper.)<\/span><\/th>\n<\/tr>\n<tr>\n<td align=\"center\">HL Tau<\/td>\n<td align=\"center\">04:31:38.4<\/td>\n<td align=\"center\">+18:13:59<\/td>\n<td align=\"center\">2.35 \u00b1 0.08<\/td>\n<td align=\"center\">2.36 \u00b1 0.09<\/td>\n<td align=\"center\">9.4 \u00b1 1.3<\/td>\n<td align=\"center\">10.4 \u00b1 1.4<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">CRL 618<\/td>\n<td align=\"center\">04:42:53.6<\/td>\n<td align=\"center\">+36:06:53.7<\/td>\n<td align=\"center\">4.6 \u00b1 0.2<\/td>\n<td align=\"center\">4.7 \u00b1 0.12<\/td>\n<td align=\"center\">10.9 \u00b1 0.9<\/td>\n<td align=\"center\">11.8 \u00b1 0.6<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">OH 231.8<\/td>\n<td align=\"center\">07:42:16.9<\/td>\n<td align=\"center\">-14:42:49.1<\/td>\n<td align=\"center\">Variable<\/td>\n<td align=\"center\">Variable<\/td>\n<td align=\"center\">Cannot be used<\/td>\n<td align=\"center\">Cannot be used<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">IRC 10216<\/td>\n<td align=\"center\">09:47:57.4<\/td>\n<td align=\"center\">+13:16:43.7<\/td>\n<td align=\"center\">Variable<\/td>\n<td align=\"center\">Variable<\/td>\n<td align=\"center\">Cannot be used<\/td>\n<td align=\"center\">Cannot be used<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">16293-2422<\/td>\n<td align=\"center\">16:32:22.9<\/td>\n<td align=\"center\">-24:28:35.6<\/td>\n<td align=\"center\">15.1 \u00b1 0.8<\/td>\n<td align=\"center\">22.9 \u00b1 1.1<\/td>\n<td align=\"center\">62.7 \u00b1 9.4<\/td>\n<td align=\"center\">169.6 \u00b1 21.2<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">CRL 2688<\/td>\n<td align=\"center\">21:02:18.8<\/td>\n<td align=\"center\">+36:41:37.7<\/td>\n<td align=\"center\">5.9 \u00b1 0.2<\/td>\n<td align=\"center\">6.4 \u00b1 0.2<\/td>\n<td align=\"center\">22.0 \u00b1 2.7<\/td>\n<td align=\"center\">29.7 \u00b1 2.1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The previous version of this document supplied fluxes for OH 231.8 and IRC 10216 at 450 \u00b5m; however, later data does not support these numbers. The two sources are clearly variable at 850 \u00b5m and it is likely that they are at 450 \u00b5m also; the scatter in the data is too large to fit a curve.<\/p>\n<p>Calibration has not been attempted at 350\/750 micron, and very few 1350um data were available before the filter drum broke in 1999. However, numbers are still available upon request.<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Primary Calibrators Uranus and Mars are used as the primary calibrators for SCUBA-2. Calibrators for SCUBA-2 are observed with a DAISY pattern which is optimised for point-like and compact sources. When determining the standard FCF numbers the data were reduced using the SMURF routine makemap. The total flux for each\u2026 <a class=\"continue-reading-link\" href=\"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/continuum\/scuba-2\/calibration\/calibrators\/\">Continue reading<\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"parent":180,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/2915"}],"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\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/comments?post=2915"}],"version-history":[{"count":32,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/2915\/revisions"}],"predecessor-version":[{"id":9265,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/2915\/revisions\/9265"}],"up":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/180"}],"wp:attachment":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/media?parent=2915"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}