{"id":37,"date":"2017-01-03T19:37:00","date_gmt":"2017-01-03T18:37:00","guid":{"rendered":"http:\/\/frantzmartinache.eu\/?p=37"},"modified":"2017-01-04T17:51:44","modified_gmt":"2017-01-04T16:51:44","slug":"uv-coverage","status":"publish","type":"post","link":"https:\/\/frantzmartinache.eu\/index.php\/2017\/01\/03\/uv-coverage\/","title":{"rendered":"uv-coverage"},"content":{"rendered":"<h1>Interferometric arrays and spatial frequencies<\/h1>\n<p>This post features a pretty fun simulation tool that will allow you to experience &#8220;by hand&#8221; the relation between the geometry of an interferometric array (that is the location of the telescopes or apertures making up the array) and the corresponding so called &#8220;uv-coverage&#8221;, that shows all the spatial frequencies the interferometric array gives access to.<br \/>\n<nbsp;><br \/>\nThe left-hand side plot shows the arangement of apertures. The user can select from several pre-set configurations (Y-shaped, hexagonal-grid, non-redundant) and modify them by moving, adding or removing individual apertures.<br \/>\n<nbsp;><br \/>\nMoving one aperture by hand and observing what simultaneously happens on the right-hand side display is particularly &#8220;enlightening&#8221;: for one, you develop a more intuitive of the relation between one aperture and the different interferometric baselines it is involved with. In addition, you can also observe that geometries laying on a regular grid pattern sometimes result in overlapping points in the uv-plane. The only pattern that strictly avoids this situation is the non-redundant geometry.<br \/>\n<nbsp;><\/p>\n<table border=\"1\">\n<tr>\n<td>\n<label for=\"array_select\" style=\"vertical-align:middle; font-size:100%;\"><br \/>\n<b>Select array pre-set:<\/b><\/label><br \/>\n<select name=\"array_select\" id=\"array_select\" onchange=\"set_update_array()\"><option value=\"triangle\" selected   >Triangle   <\/option><option value=\"square\"            >Square       <\/option><option value=\"golay9\"            >Golay 9-hole <\/option><option value=\"other9\"            >Other 9-hole <\/option><option value=\"Y\"                 >Y-shaped     <\/option><option value=\"sq_grid\"           >Square grid  <\/option><option value=\"hex\"               >Hex. grid    <\/option><option value=\"ring15\"            >Annulus15    <\/option><option value=\"ring9\"             >Annulus9     <\/option><option value=\"ring10\"            >Annulus10    <\/option><\/select>\n<\/td>\n<\/tr>\n<tr>\n<td><canvas id=\"cnvs1\" width=\"300\" height=\"300\">??<\/canvas><\/td>\n<td><canvas id=\"cnvs2\" width=\"300\" height=\"300\">??<\/canvas><\/td>\n<\/tr>\n<tr>\n<td>\n<table>\n<tr>\n<td><input type=\"button\" onclick=\"add_apert()\" value=\"ADD aperture\" size=\"1\" style=\"width:100px; height:40px\"><\/td>\n<td><input type=\"button\" onclick=\"rmv_apert()\" value=\"RMV aperture\" size=\"1\" style=\"width:100px; height:40px\"><\/td>\n<\/tr>\n<tr>\n<td><input type=\"button\" onclick=\"scale_up()\" value=\"scale UP\" style=\"width:100px; height:40px\"><\/td>\n<td><input type=\"button\" onclick=\"scale_down()\" value=\"scale DOWN\" style=\"width:100px; height:40px\"><\/td>\n<\/tr>\n<\/table>\n<\/td>\n<td><b>Resulting uv-coverage<\/b><\/td>\n<\/tr>\n<\/table>\n<p><script type=\"text\/javascript\" src=\"\/scripts\/uv_coverage.js\"><\/script><\/p>\n<p>This tool was developed as a part of the on-line course <a href=\"http:\/\/www.fun-mooc.fr\/courses\/oca\/27001\/Trimestre_1_2015\/about\">Eagle Eye Astronomy<\/a>, hosted on the <a href=\"http:\/\/www.fun-mooc.fr\/\">France Universit\u00e9 Num\u00e9rique<\/a> website.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Interferometric arrays and spatial frequencies This post features a pretty fun simulation tool that will allow you to experience &#8220;by hand&#8221; the relation between the geometry of an interferometric array (that is the location of the telescopes or apertures making up the array) and the corresponding so called &#8220;uv-coverage&#8221;, that shows all the spatial frequencies &hellip; <a href=\"https:\/\/frantzmartinache.eu\/index.php\/2017\/01\/03\/uv-coverage\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">uv-coverage<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,4],"tags":[],"_links":{"self":[{"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/posts\/37"}],"collection":[{"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/comments?post=37"}],"version-history":[{"count":25,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/posts\/37\/revisions"}],"predecessor-version":[{"id":49,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/posts\/37\/revisions\/49"}],"wp:attachment":[{"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/media?parent=37"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/categories?post=37"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/frantzmartinache.eu\/index.php\/wp-json\/wp\/v2\/tags?post=37"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}