{"id":1537,"date":"2013-06-11T09:33:51","date_gmt":"2013-06-11T17:33:51","guid":{"rendered":"http:\/\/jazzistentialism.com\/blog\/?p=1537"},"modified":"2015-09-17T22:14:48","modified_gmt":"2015-09-18T06:14:48","slug":"differential-photometry-analysis-using-maxim-dl","status":"publish","type":"post","link":"https:\/\/jazzistentialism.com\/blog\/?p=1537","title":{"rendered":"Differential photometry analysis using MaxIM DL"},"content":{"rendered":"

\"Screen<\/a><\/p>\n

The following analysis investigates the accuracy of magnitude measurements using MaxIM DL’s\u00a0information<\/em>\u00a0tool in aperture mode,\u00a0by plotting instrument magnitude against published magnitude for a Landolt field.<\/p>\n

<\/p>\n

Two sets of measurements were made:<\/p>\n

    \n
  1. Instrumental magnitude, based on an arbitrary zero point.<\/li>\n
  2. V-band measurements of Landolt stars based on calibration of one of Landolt star in the field.<\/li>\n<\/ol>\n

    Image details<\/h2>\n

    Date: 130610
    \nTelescope: RC14C, 1.4 arc seconds per pixel.
    \nCamera: Apogee Alta U16M (KAF-16803, ABG)
    \nAir: 1.172
    \nCCD Temp. -30
    \nAltitude of field at image time 58\u00b0<\/p>\n

    Landolt field centred at \u00a0RA 11 57 43.0 \u00a0Dec -00 30 37.0<\/p>\n

    \"Screen

    Figure 1: Landolt field as displayed in TheSkyX<\/p><\/div>\n

    All images were acquired\u00a0using a\u00a0V band filter.<\/p>\n

    Exposures from 10s to 120s were taken in order to determine best star saturation for measurement. An average of 3 x 30s exposures were used for analysis.<\/p>\n

    \"Screen<\/a>

    Figure 2: Calibrated FITS image<\/p><\/div>\n

    Results<\/h2>\n

    Instrumental magnitude was determined using the formula:<\/p>\n

    IM<\/em>\u00a0= -2.5log(ADU)<\/em><\/p>\n

    Where \u201cADU<\/em>\u201d = intensity value in MaxIM information dialogue.<\/p>\n

    (From the MaxIM DL documentation, intensity =\u00a0 sum of pixels within aperture \u2013 background.)<\/em><\/p>\n

    V magnitude was measured in\u00a0MaxIM DL<\/em>\u00a0by calibrating Landolt star 103-256 to published V value, and then using the aperture to measure each of the other stars within MaxIM DL’s\u00a0information\u00a0<\/em>tool.<\/em><\/p>\n

    \"Screen<\/a><\/p>\n

    \"Screen<\/a>

    Figure 3: Differential photometry analysis showing instrumental magnitude vs V magnitude<\/p><\/div>\n

    Conclusion<\/h2>\n

    The results show very good correlation, considering it represents photometry using the\u00a0information<\/em>\u00a0tool, rather than the more accurate\u00a0photometry<\/em>\u00a0tool in\u00a0MaxIM DL<\/em>.<\/p>\n

    Magnitude measurements using MaxIM DL’s aperture tool appear to be accurate to an average of 0.003 mag for the targests used in this exercise.<\/p>\n","protected":false},"excerpt":{"rendered":"

    The following analysis investigates the accuracy of magnitude measurements using MaxIM DL’s\u00a0information\u00a0tool in aperture mode,\u00a0by plotting instrument magnitude against published magnitude for a Landolt field.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[20],"tags":[],"_links":{"self":[{"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1537"}],"collection":[{"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1537"}],"version-history":[{"count":2,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1537\/revisions"}],"predecessor-version":[{"id":1622,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1537\/revisions\/1622"}],"wp:attachment":[{"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1537"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jazzistentialism.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}