"imnew": "comet-model2.fits",       # give image name to be created
    "helio": 1.0,                       # give heliocentric distance to comet in au
    "obsdist": 1.0,                     # give the observatory-to-comet distance in au
    "pixscale": 1.0,                    # give pixel scale in arcsec per pixel
    "arlon": 0.0,                       # give cometographic longitude of center of active region
    "arlat": 60.0,                      # give cometographic latitude of center of active region
    "arradius": 5.0,                    # give radius of the active region in degrees [<90 deg]
    "stdevjet": 0.2,                    # give std dev for radial dispersion of first generation in deg
    "angmora": 0.0,                     # give RA of ang mom in cometocentric system in deg
    "angmodec": 90.0,                   # give Dec of ang mom in cometocentric system in deg
    "solra": 0.0,                       # give RA of Sun direction in degrees
    "soldec": 0.0,                      # give Dec of Sun direction in degrees
    "obsra": 0.0,                       # give RA of Earth direction in degrees
    "obsdec": 0.0,                      # give Dec of Earth direction in degrees
    "rotperi": 2.0,                     # give rotation period in days
    "obstime": 1.0,                     # give the time of observation in days from reference time
    "angleref": 0.0,                    # give the ref angle for zero long at reference time (in deg)
    "radpr1st": 0.0,                    # give rad pressure acc in cm/sec/sec for a first generation at 1 AU
    "radpr2nd": 0.0,                    # give rad pressure acc in cm/sec/sec for a second generation at 1 AU
    "vel1st": 0.4,                      # give the mean first generation velocity in km/sec
    "vel2nd": 0.0,                      # give second generation velocity in km/sec
    "life1st": 1,                       # give exponential decay time for second generation prod rate in days
    "life2nd": 100000000,               # give life time of the second generation in days
    "timebin": 1000,                    # give time bin size in days
    "timetot": 8640000,                 # give the maximum time particles to be followed in days
    "timeact": 8640000,                 # give the duration of the activity (at start) in days
    "nlocates": 10.0,                   # give number of locations of active region to sample per bin
    "maxbin": 10.0,                     # give max first generations to be emitted per location and per bin
    "ambient": 0.0,                     # give constant bg prod rate as a fraction of max prod rate
    "ninsol": 0,                        # is prod rate independent of insolation? (yes=0,no=other num)