Re: Transit Fitting plus referencing software in paper

Posted by karenacollins on Feb 02, 2015; 12:35pm
URL: http://astroimagej.170.s1.nabble.com/Transit-Fitting-plus-referencing-software-in-paper-tp199p243.html

Hi David,

You should get the same result with both methods (after combining in the
first case). In the second case, if you enable "Use RA/Dec to locate
aperture positions" and also enable "Reposition aperture to object
centroid", the centroid operation still occurs based on the starting
point as defined by aperture's RA/DEC location (so the aperture should
still find the star's center). If you are getting different results,
send me more details to investigate.

If you are observing exoplanet transits and are fitting the data to a
transit model in Multi-Plot, but sure and include the "meridian flip"
detrend parameter and place the 'meridian Flip' 'Flip Time' at the time
of the meridian flip (controlled on lower-left of the Multi-plot Main
panel). This will model out any offset induced by the different
positions of stars on the CCD.

Yes, the append option is intended to combine two sets of data into one
measurements table /plot. For your case, you should use 'Append as new
ROWS' to create a single dataset. If you are combining datasets to plot
more that one light curve, use 'Append as new COLUMNS' so that each of
the data columns in the two data sets will have a suffix appended to the
data column names (such as _A and _B (use something short)) which will
facilitate plotting the datasets with independent X and Y columns as needed.

By the way, if you are combining data before and after a meridian flip,
you should use the same comp star ensemble in both photometry runs (and
same aperture settings). in other words, if a comp star is on the
detector before meridian flip and not after, don't use it in either case.

Karen