{"id":2862,"date":"2015-02-28T12:04:30","date_gmt":"2015-02-28T12:04:30","guid":{"rendered":"https:\/\/www.geoptik.com\/?product=flat-field"},"modified":"2026-01-06T21:30:24","modified_gmt":"2026-01-06T21:30:24","slug":"flat-field","status":"publish","type":"product","link":"https:\/\/www.geoptik.com\/en\/prodotto\/flat-field\/","title":{"rendered":"Flat Field"},"content":{"rendered":"<p style=\"font-size: 14px; line-height: 21px;\"><img alt=\"\" src=\"http:\/\/www.geoptik.com\/image\/data\/Strumenti misura\/New led.jpg\" style=\"width: 520px; height: 74px;\" \/><\/p>\n<p style=\"font-size: 14px; line-height: 21px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Image calibration is a very important first step in the processing of an astronomical image.<br \/>\nLight Frames&#8217; are images (or a video) of a celestial object captured by the CCD.<br \/>\nEach pixel in the images will have a numeric value that includes the influences of:<\/span><\/span><\/p>\n<ul>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Light from the celestial objects in the field of view.<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">The various types of noise generated by the CCD.<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Defects in the optical system.<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">CCD inhomogeneities (pixels more or less sensitive to light)<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Optical vignetting (image is darker away from the centre)<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Dust on the CCD window (seen as &#8216;donut&#8217; shaped spots on the image)<\/span><\/span><\/li>\n<li style=\"font-size: 14px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">Internal reflections<\/span><\/span><\/li>\n<\/ul>\n<p style=\"font-size: 14px; line-height: 21px;\"><span style=\"font-size:12px;\"><span style=\"font-family: verdana,geneva,sans-serif;\">With calibration we will try to remove as much as possible of the Bias and Dark Current from each Light Frame.<br \/>\nAlso, we will try to remove the effects of certain types of optical defect.<br \/>\n<span id=\"result_box\" lang=\"en\"><span class=\"hps alt-edited\">It has<\/span> <span class=\"hps\">a rheostat<\/span> <span class=\"hps\">for adjusting<\/span> <span class=\"hps\">the light intensity<\/span>.<br \/>\n<span class=\"hps\">Cigarette lighter cable<\/span> <span class=\"hps\">included<\/span><span>.<br \/>\n<span id=\"result_box\" lang=\"en\"><span class=\"hps\">With its three<\/span> <span class=\"hps\">plastic screws<\/span> <span class=\"hps\">you can<\/span> <span class=\"hps alt-edited\">fix<\/span> <span class=\"hps\">to<\/span> <span class=\"hps\">telescopes<\/span> <span class=\"hps\">with<\/span> <span class=\"hps\">diameters from<\/span> <span class=\"hps\">292<\/span> <span class=\"hps\">to 372<\/span> <span class=\"hps\">mm<\/span><\/span><\/span><\/span><\/span><\/span><br \/>\n&nbsp;<\/p>\n<p style=\"font-size: 14px; line-height: 21px;\"><img loading=\"lazy\" alt=\"\" height=\"427\" src=\"http:\/\/www.geoptik.com\/image\/data\/Strumenti misura\/Flat field frame.jpg\" width=\"561\" \/><\/p>\n<p><iframe loading=\"lazy\" frameborder=\"0\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/2hlOtF5H56s?rel=0\" width=\"560\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Image calibration is a very important first step in the processing of an astronomical image. Light Frames&#8217; are images (or a video) of a celestial object captured by the CCD. Each pixel in the images will have a numeric value that includes the influences of: Light from the celestial objects in the field of view. [&hellip;]<\/p>\n","protected":false},"featured_media":1742,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_cat":[118],"product_tag":[],"_links":{"self":[{"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/product\/2862"}],"collection":[{"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/comments?post=2862"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/media\/1742"}],"wp:attachment":[{"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/media?parent=2862"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/product_cat?post=2862"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.geoptik.com\/en\/wp-json\/wp\/v2\/product_tag?post=2862"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}