Re: Detrending

Posted by karenacollins on Mar 24, 2017; 6:52pm
URL: http://astroimagej.170.s1.nabble.com/Detrending-tp638p640.html

Hi Brad,

Detrending is explained mathematically in Section 4.4 and equation 5 of the AIJ paper available here on arXiv:

http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2017arXiv170104817C&link_type=PREPRINT&db_key=PRE

At a high level, first the best linear fit of a "trend" data set (such as airmass) to the light curve is found. That
results in a coefficient that is used to produce a scaled version of the trend dataset that is then subtracted from (or
divided into - if that option is selected) the light curve to remove the trend from the light curve dataset. The region
of the light curve used to find the best fit coefficient is defined by the "fit mode" selected on the "Multi-plot
Y-data" panel and the "left" and "right" markers on the "Multi-plot Main" panel. If the exoplanet transit light curve
fitting mode is selected, the full light curve is used, but the linear fit of the trend data set(s) is found
simultaneously with the best fitting transit model.

Karen