{"id":9366,"date":"2019-04-23T08:00:33","date_gmt":"2019-04-23T18:00:33","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?p=9366"},"modified":"2020-12-29T11:02:03","modified_gmt":"2020-12-29T21:02:03","slug":"a-new-dimmconfig-that-uses-pca","status":"publish","type":"post","link":"https:\/\/www.eaobservatory.org\/jcmt\/2019\/04\/a-new-dimmconfig-that-uses-pca\/","title":{"rendered":"A new dimmconfig that uses PCA"},"content":{"rendered":"

The $STARLINK_DIR\/share\/smurf <\/span>directory <\/span><\/span>includes several “dimmconfig” files that package up commonly used groups of configuration parameter values for use by the makemap<\/span> command.\u00a0 A new file called dimmconfig_pca.lis<\/span> has recently been added, which can be combined with\u00a0 other dimmconfig files to tell makemap<\/span> to include a PCA model in its iterative algorithm (the PCA model removes noise signals that are correlated between multiple bolometer time-streams). For instance, to use a PCA model when creating a map of a bright extended source, you could run makemap<\/span> as follows:<\/p>\n

% more conf<\/span>\r\n^$STARLINK_DIR\/share\/smurf\/dimmconfig_bright_extended.lis<\/span>\r\n^$STARLINK_DIR\/share\/smurf\/dimmconfig_pca.lis<\/span>\r\n% makemap config=^conf<\/span><\/pre>\n
To process compact sources, change “bright_extended<\/span>” above to “bright_compact<\/span>“.<\/p>\n
Using a PCA model can help to reduce the spurious extended structures that often appear in SCUBA-2 maps (although this benefit is bought at the cost of a much extended run time). For instance, below are four 850 um maps of DR 21 – the top row shows the maps made with the basic “bright extended” dimmconfig, and the bottom shows eh results of adding in the new PCA dimmconfig:<\/p>\n
\"\"<\/a><\/p>\n
Below are the mosaics of the four observations, with the difference map shown in between:<\/p>\n
\"\"<\/a><\/p>\n
As another example, the following panes show similar maps for three observations of the Serpens South field:<\/p>\n
\"\"<\/a><\/p>\n
\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
The $STARLINK_DIR\/share\/smurf directory includes several “dimmconfig” files that package up commonly used groups of configuration parameter values for use by the makemap command.\u00a0 A new file called dimmconfig_pca.lis has recently been added, which can be combined with\u00a0 other dimmconfig files to tell makemap to include a PCA model in its\u2026 Continue reading<\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[36],"tags":[39,46,47],"_links":{"self":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9366"}],"collection":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/comments?post=9366"}],"version-history":[{"count":6,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9366\/revisions"}],"predecessor-version":[{"id":9376,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9366\/revisions\/9376"}],"wp:attachment":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/media?parent=9366"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/categories?post=9366"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/tags?post=9366"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}