horizons.exp

#!/usr/bin/expect -f
#An expect script to get the horizons ephemeris. 
#Intended to interface with IDL get_eph.pro

#Thanks to bbutler for posting his very similar script online, 
#from which this was based

#long timeout required to generate large requests
set timeout 300

#read in the command line arguments
set naifid [lindex $argv 0]
set starttime [lindex $argv 1]
set endtime [lindex $argv 2]
set stepsize [lindex $argv 3]
set center [lindex $argv 4]
set filename [lindex $argv 5]

set env(TERM) no-resize-vt100
spawn telnet ssd.jpl.nasa.gov 6775
expect "Horizons> " { send "load vla-1\r" }
expect "Horizons> " { send page\r }
expect "Horizons> " { send $naifid\r }
expect -re ".*Select.*: $" { send e\r }
expect -re ".*Observe.*: $" { send v\r }
expect -re ".*Coordinate.*: $" { send @$center\r }
expect -re ".*Reference.*: $" { send frame\r }
expect -re ".*Starting.*: $" { send $starttime\r }
expect -re ".*Ending.*: $" { send $endtime\r }
expect -re ".*interval.*: $" { send $stepsize\r }
expect -re ".*Accept.*: $" { send n\r }
expect -re ".*reference.*: $" { send J2000\r }
expect -re ".*Corrections.*: $" { send 1\r }
expect -re ".*units.*: $" { send 2\r }
expect -re ".*CSV.*: $" { send yes\r }
expect -re ".*delta-T.*: $" { send no\r }
expect -re ".*Select.*: $" { send 1\r }

set outf $filename
log_file -noappend "$outf"
expect -re ".*>>> Select.*:" { send "q\r" }
send_user "\n"
log_file

exit 0