Timestamp fits files for SAGE epoch1 only and epoch2 only source lists The timestamp fits files are good to the times of the *individual IRAC frames*. There are two fits files for each band for each epoch (16 files), one that shows the earliest possible observation time, and one that shows the latest possible observation time. The fits image units are "Minutes past Julian Date 2453500.5" as stated in the fits header. The fits files are 2" pixels. The files are: Epoch1 SAGE_LMC_IRAC1_E1.earliest_obstime.fits.gz SAGE_LMC_IRAC1_E1.latest_obstime.fits.gz SAGE_LMC_IRAC2_E1.earliest_obstime.fits.gz SAGE_LMC_IRAC2_E1.latest_obstime.fits.gz SAGE_LMC_IRAC3_E1.earliest_obstime.fits.gz SAGE_LMC_IRAC3_E1.latest_obstime.fits.gz SAGE_LMC_IRAC4_E1.earliest_obstime.fits.gz SAGE_LMC_IRAC4_E1.latest_obstime.fits.gz The region files for each are: SAGE_LMC_IRAC1_E1.reg SAGE_LMC_IRAC2_E1.reg SAGE_LMC_IRAC3_E1.reg SAGE_LMC_IRAC4_E1.reg Epoch 2 SAGE_LMC_IRAC1_E2.earliest_obstime.fits.gz SAGE_LMC_IRAC1_E2.latest_obstime.fits.gz SAGE_LMC_IRAC2_E2.earliest_obstime.fits.gz SAGE_LMC_IRAC2_E2.latest_obstime.fits.gz SAGE_LMC_IRAC4_E2.earliest_obstime.fits.gz SAGE_LMC_IRAC4_E2.latest_obstime.fits.gz SAGE_LMC_IRAC3_E2.earliest_obstime.fits.gz SAGE_LMC_IRAC3_E2.latest_obstime.fits.gz The region files for each are: SAGE_LMC_IRAC1_E2.reg SAGE_LMC_IRAC2_E2.reg SAGE_LMC_IRAC3_E2.reg SAGE_LMC_IRAC4_E2.reg ============================================================================= The IDL program get_sage_jd.pro which when given an input RA & Dec, and the appropriate timestamp fits file, outputs the earliest (or latest) MJD. It will now take either a single position or an array of positions. There are examples of usage in the IDL program.