The uvotmaghist tool uses uvotsource on all the given extensions of an image to create a light curve.
> uvotmaghist Name of input image file[ ]: sw00374210000uuu_sk.img.gz Name for output magnitude history[ ]: maghistU.fits Name for output magnitude history plot or NONE[ ]: maghistU.gif Name of zero points file or CALDB[ ]: CALDB Name of coincidence loss file or CALDB[ ]: CALDB Source region file or NONE[ ]: Usource.reg Background region file or NONE[ ]: Uback.reg
The gif output file is a plot of magnitudes with time, though this can be changed using the plotcol command. One point will be plotted for each extension of the image. If any of these are non-detections (at the 3-sigma level, by default), the point will be plotted with just a negative error bar, as in the following example:
The FITS file output contains a table of those magnitudes and errors plus count rates and fluxes. Thus, the user can make their own plot, rather than using the one produced automatically by uvotmaghist.