ntaps=saved value of tape sequence number
jiabs1=0,1 or 2 indicates which variable is used for logical
tape number
jtape=1 to 10 index for logical tape number variable

the following integers read from iabs1 indicate which partial
derivatives are on iabs1
mprm   solar system parameters in /param/
mem    earth-moon barycenter initial conditions and earth parameters
mmn    moon initial conditions and parameters
mer    earth rotation initial conditions and parameters
mmr    moon rotation initial conditions and parameters
mpl    planet initial conditions and parameters
mscrd  observing site coordinates
meqn   equinox-equator-latitude corrections for optical obs series
mphs   planetary phase corrections for optical observation series
interpolation y-vectors and temporary storage