- Add planet orientation parameters (plmaj,plmin,plangle) to the dataset. uvplanet recognises planets by their source name, and knows their orientations as a function of time. - Apply a time-varying phase shift to track the object. - Subtract a thermal disk. - Subtract background sources, accounting for a moving phase centre.
replace Replace the data with the blackbody disk and point sources (the normal behaviour is to subtract the blackbody disk and point sources). magnetic For Jupiter only: The magnetic axis is used to set planet orientation parameters. This overrides the normal behaviour of using the spin axis. arcane The format for the pmotion text files is the "arcane" format (see below).The following options can be used to turn off calibration corrections. The default is to apply any calibration present.
nocal Do not apply the gains table. nopass Do not apply bandpass corrections. nopol Do not apply polarization corrections.
ra dec fluxThe RA and DEC are in normal Miriad format, and the flux is in Jy.
The "pmotion" parameter can also be used to correct the RA and DEC stored in the dataset. If these are incorrect (e.g. many telescopes and the FITS format, do not store the time-varying RA/DEC, even though they track time varying RA/DEC), then giving the one text file twice will cause the RA and DEC to be corrected and no shifts being applied.
The text files contain potentially many lines, with each line giving a sky position at a given time. Two formats for the text files are possible (if there are two input files, both must be in the same format). The normal format consists of 3 values per line, being
time ra dec
with "time" (UTC), "ra" and "dec" being the position of the object at a given time. The time, ra and dec are in the normal Miriad formats. The times should be in increasing order. Linear interpolation is used to estimate positions between the given times.
A convenient way to develop this file is through the JPL ``Horizons'' service. This is accessed through
telnet ssd.jpl.nasa.gov 6775
Using a text reformating tool (e.g. PERL), the output from Horizons is readily converted to the format required by uvplanet. Documentation on the Horizons system is available from
The other possible format is the ``arcane'' format, which will be expected if "options=arcane" is given. This format is provided for obscure historical support. It consists of 6 values per line, being
start_time time ra dec dra ddec
The times are in modifed Julian days, ra and dec are in turns, and the rate parameters, "dra" and "ddec", are in turns/day. The record is considered valid after "start_time", and the rates are used to estimate positions between given times.