The ARGOS calibration unit swing arm position is not available into the snapshot, but it is used to distinguish between daytime and on-sky data. This information must be added manually:

1. Open a snapshot analyzer terminal and type:

ds= terminal.set('tn_init', 'tn_end')
tweakers= ds.tweakers()
for tw in tweakers: tw.headerUpdateKey('HIERARCH CAL.SWING_ARM.IS_IN', True)

-- MarcoBonaglia - 03 Jul 2015