The ni-lightcurve script is a simple nicerlab implementation for constructing light curves from event files. Basic usage is

ni-lightcurve evt.meta

By default ni-lightcurve will output count-rates as a function of MJD using a 16 second time resolution. All data is written to a single ASCII file named lc.dat, with a continuous block for each good time interval. Good time intervals are read from the fits file.

--dt Set the time resolution
--clobber Overwrite the outputfile is it exists
--met Format the time axis as mission-elapsed time
--output Set the output file name
--help Display usage instructions


The gti-select tool gives an interactive method for shaping an event file’s good time interval table. Basic usage is as

gti-select evt.meta --dt 1
--dt Set the time resolution
--clobber Overwrite the eventfile internal GTI table
--help Display usage instructions

After initialization gti-select will iterate through the event files listed in the metafile. For each event file it will construct a light curve at the requested resolution and produce a plot with the current GTI’s overlayed. One can then use the mouse to shape the good time intervals, and the terminal to move to the next event file. The available controls are

left-mouse Add bad time
right-mouse Add good time
type ‘undo’ Reset the current event file
type ‘quit’ Quit without saving current file
type <enter> Save and go to next file