Measurements file as input

[SCO]

Can the Measurements file be used as input for AstroImageJ rather than the actual .fits files?  If so, is the procedure documented somewhere?

Can a subset of the Measurements file (see attached) be used as input to AstroImageJ if missing parameters are input in the panels"?



Thanks,
Ed

[karenacollins]

Yes, use the option in the multi-aperture main file menu.

Yes, the minimum is a time column such as JD_UTC, a flux column (rel_flux_T1 or whatever you'd like to call it), and a flux error column (rel_flux_err_T1 is you use the above suggestion for flux). Then you can plot, fit, etc. You'd need to supply other columns for detrending if you want to detrend.

Karen

[SCO]

Thanks Karen.  If I want to detrend, what columns are necessary?

Ed

[karenacollins]

Only the columns you want to detrend against are needed. Detrending is not required. For instance, airmass is probably the most used detrending parameter. If I recall our last conversation about detrending correctly, you are not detrending transit observations. You could still detrend those in AIJ, but you'd need sections of data that you expect should be flat within the lightcurve scatter (similar to the pre-ingress and post-egress baseline for a transit light curve). Other columns that are sometimes useful for detrending are sky background, FWHM, x-center, y-center (of a star on the detector), and time. Beware of fitting too many detrending parameters in AIJ. You can flatten any lightcurve with too much detrending. If you only have short segments of equivalent baseline, compared to the overall lightcurve duration, you should consider not detrending, or use airmass-only detrending. In all cases, I'd limit to a couple of detrend parameters that are justified by the BIC numbers that the AIJ fitting panel provides.

[SCO]

Sounds great.  Thanks Karen.

Ed