I am trying to get a list of all of Mercury's Perihelia and Aphelia over a period of multiple decades. For each event I need X,Y,X and Vx,Vy,Vz data.
Knowing the time of the first event it is easy to obtain approximate times of the subsequent events using the known orbital period.
I have managed to acquire values using the manual web interface to JPL Horizons. Working on one event at a time I can get data for an epoch within one minute of each event. But I want (a) timings to the nearest second and (b) to obtain a whole series of apsides events in one go.
The JPL Horizons email interface seems to be the way to go. Using this I have been able to obtain data for a particular time range and step interval. But, as with the web interface, it is not possible (in one go) to cover the whole multi-decade period at the desired resolution (1s).
So now I want to use the TLIST facility to specify a list of individual event times (times at 1s intervals within a range from several seconds before and after the approximate time of each apsides event).
The documentation - see how to get Horizons email documentation mailed to you - includes this section on TLIST:-
!TLIST allows users to specify up to 10000 discrete times !individually. If TLIST is used, START_TIME, STOP_TIME and !STEP_SIZE are ignored. TLIST is a list of either "Julian !Day Numbers" (JD) or "Modified Julian Day Numbers" !(MJD; days since Nov 17, 1858 (JD 2400000.5)). !In either case, the input is one or more real numbers. !The program puts TLIST in ascending chronological order !and determines whether it is JD or MJD based on smallest !day number. Example usage: ! ! TLIST= '2451454.8937833' '2451455.11256351' ! '2451456.45576728' ! '2451459.65778822' ! '2451458.97618331' ! '2451459.72787832' ! '2451462.25656722' ! ! Note that there can be more than one value on the line ! OR one per line. Line length should be less than 80 ! characters. List is space or comma delimited. "TLIST=" ! is used only once so it does not supercede any previous ! assignment in the command file. TLIST = 200*' '
But I am having a problem in formatting the TLIST input data in a way that the program will accept. Every attempt so far has returned an error message of the form "BATVAR: cannot read TLIST value: --F4F5E805D2040CE6C2".
I have emailed the system manager but have had no response so far.
Below is a copy of the email text which I have been sending (format = To: [email protected] Subject: JOB ****** ).
I would be grateful if anyone can suggest what needs to be done with the data format for the TLIST command.
!$$SOF EMAIL_ADDR = '************@gmail.com' !...Target= Mercury COMMAND= '199' !...Reference Site = Centre of Sun CENTER= '500@10' MAKE_EPHEM= 'YES' TABLE_TYPE= 'VECTORS' OUT_UNITS= 'KM-S' REF_PLANE= 'ECLIPTIC' REF_SYSTEM= 'J2000' VECT_CORR= 'NONE' VEC_LABELS= 'YES' VEC_DELTA_T= 'YES' CSV_FORMAT= 'YES' OBJ_DATA= 'YES' VEC_TABLE= '2' ! ! The following works OK (but I want to use TLIST) ! !START_TIME= 'JD 2451590.2526841' !STOP_TIME= 'JD 2451590.2596841' !STEP_SIZE= '1 m' ! ! ! What I desire (but it fails):- ! !TLIST= !'2451546.2714931' !'2451546.2715046' !'2451546.2715162' !'2451546.2715278' !'2451546.2715393' !'2451546.2715509' !'2451546.2715625' ! ! Test (it failed) ! TLIST= '2451454.8937833,2451455.11256351,' '2451456.45576728,' '2451459.65778822,' '2451458.97618331,' '2451459.72787832,' '2451462.25656722' ! ! ! The Following Fail:- ! ! TLIST= 'JD 2451454.8937833' 'JD 2451455.11256351' ! 'JD 2451456.45576728' ! 'JD 2451459.65778822' ! 'JD 2451458.97618331' ! 'JD 2451459.72787832' ! 'JD 2451462.25656722' ! ! TLIST= '2451454.8937833' '2451455.11256351' ! '2451456.45576728' ! '2451459.65778822' ! '2451458.97618331' ! '2451459.72787832' ! '2451462.25656722' ! !TLIST= '2451546.27149310' '2451546.27149310' ! '2451546.27150460' ! !TLIST= '2451546.2714931' '2451546.2714931' ! '2451546.2715046' ! !TLIST= ' ! 2451546.2714931 ! 2451546.2715046 ! 2451546.2715162' ! !TLIST= ' ! 2451546.2714931, ! 2451546.2715046, ! 2451546.2715162' ! !TLIST= ''2451546.2714931', '2451546.2715046', '2451546.2715162'' ! !TLIST= '2451546.2714931', '2451546.2715046', '2451546.2715162' ! !TLIST= '2451546.2714931' '2451546.2715046' '2451546.2715162' ! !TLIST= '2451546.2714931 2451546.2715046 2451546.2715162' ! !TLIST='2451546.2714931,2451546.2715046,2451546.2715162' ! !TLIST=200*'' ! !TLIST= '2451454.8937833' '2451455.11256351' ! !TLIST= '2451546.2' ! !TLIST='2451546.2714931''2451546.2715046''2451546.2715162'!'2451546.2715278', !'2451546.2715393', !'2451546.2715509', !'2451546.2715625' ! !$$EOF