so I need to access a telnet session. More specifically JPL's ephemeris service. I know exactly what I need to do in the command prompt, but I've had trouble using the telnetlib package.
Here are the steps I need to take through command prompt:
telnet o horizons.jpl.nasa.gov 6775 DES=C/2012 X1; y E o H06 y 2013-Nov-7 9:00 2013-Nov-17 9:00 1d y 1,4,9,19,20,24
and then after that there is a large output that I need to save to a text file, or simply keep as a variable. I'll be using it later.
And following these inputs step by step should get you to the exact bit of information I need to grab
Any advice?
I would use telnetlib.Telnet.expect(), something like this:
import telnetlib t = telnetlib.Telnet() t.open('horizons.jpl.nasa.gov', 6775) expect = ( ( r'Horizons>', 'DES=C/2012 X1\n' ), ( r'Continue.*:', 'y\n' ), ( r'Select.*E.phemeris.*:', 'E\n'), ( r'Observe.*:', 'o\n' ), ( r'Coordinate center.*:', 'H06\n' ), ( r'Confirm selected station.*>', 'y\n'), ( r'Accept default output.*:', 'y\n'), ( r'Starting *UT.* :', '2013-Nov-7 09:00\n' ), ( r'Ending *UT.* :', '2013-Nov-17 09:00\n' ), ( r'Output interval.*:', '1d\n' ), ( r'Select table quant.* :', '1,4,9,19,20,24\n' ), ( r'Scroll . Page: .*%', ' '), ( r'Select\.\.\. .A.gain.* :', 'X\n' ) ) with open('results.txt', 'w') as fp: while True: try: answer = t.expect(list(i[0] for i in expect), 10) except EOFError: break fp.write(answer[2]) fp.flush() t.write(expect[answer[0]][1])
Between April and May 2013, some people actually wrote an entire Python package around JPL's Horizons Telnet interface. It can be found here:
https://pypi.python.org/pypi/HorizonJPL
