The three data cubes of dopplergrams all show the same area on the Sun
as it appears at different altitudes in the photosphere (Ni, K, and Na).
The sampling rate is one dopplergram every ten seconds. The Potassium (K)
and Sodium (Na) dopplergrams were aquired in Antarctica by the MOTH
experiment. The Nickel (Ni) dopplergrams are the contemporaneous observations
by MDI (interpolated to match the higher sampling rate of the MOTH data).


file name	line	start time [UT]		heliographic range [lon / lat]
******************************************************************************
k20v.fits	K	2003-01-20, 00:59	45.56...83.56 / -15.33...22.67
na20v.fits	Na D2	2003-01-20, 00:59	45.56...83.56 / -15.33...22.67
ni20v.fits	Ni	2003-01-20, 00:59	45.56...83.56 / -15.33...22.67