NAME	

	track	-	track astronomical sources in single dish mode

SYNOPSIS

	$SMALOCAL/bin/track source_name control_flag radio_optical

DESCRIPTION

	"track" is a fully integrated single dish version of the SMA
	antenna tracking program. This program accepts user commands
	directly from the keyboard, instead of reflective memory.
	The program runs on the antenna computer (LynxOS VXI-PC slot-0 
	controller dubbed "accn" for antenna-n).
	
	For solar system objects, the JPL ephemeris DE200 is looked up
	and the apparent RA and DEC are calculated for the time of
	observation. The GPS clock is read through the IRIG-B time-code
	reader.  For non-solar system objects, an ascii file called
	"sma_catalog" is searched for the source name entered as the
	first command line argument.  If the object is not found, the
	user is prompted to enter RA and DEC values. The apparent RA
	and DEC calculations are updated every 30 seconds, and linearly
	interpolated for intermediate times. The azimuth and elevation
	values are calculated every 0.1 seconds and communicated to the
	PMAC's Dual-Ported RAM. All motion control commands are
	communicated to the PMAC calling Bob Wilson's C functions which 
	use the mailbox registers.

	Track also controls the various states of the chopper and
        enables synchronous detection through the program "syncdet",
        which gathers data from the PMAC's dual-port RAM.

	The user-interface to "track" is provided by a simple vt-100 
	compatible display of antenna status and the following user
	input commands are implemented through hot-keys 
	(do not hit return after pressing the key).

	q: quits- after aborting the PMAC motion program, keeping 
	   the servo loops closed.
	0: zeroes the offsets, and resets the map and scan flags.
	o: opens the tertiary mirror door.
	c: closes the tertiary mirror door (and provides radiometer
	   calibration at ambient temperature). 
	a: start azimuth scan 
	e: start elevation scan 
	 or h: - az offset 
              (like in the good old LSI terminals or vi) 
	 or j: - el offset 
	 or k: + el offset
	 or l: + az offset
	u: increment offset unit by 1".
	d: decrement offset unit by 1".
	+: increment offset unit by 10".
	-: decrement offset unit by 10".
	z: reset offset unit to 0. (Can be used to stop a scan or a map).
	x: go off source in azimuth by -1800""
	X: go off source in azimuth by +1800""
	y: go off source in elevation by -1800""
	Y: go off source in elevation by +1800""
	m: start a map in azimuth and elevation 
	s: store pointing offsets along with other relevant data in an
	   ascii file called "azeldata".
	t: acquire a CCD image by executing Tony Stark's frame grabber
	   program.
	S: do both s and t above.
	2: decrement integration time for CCD camera by 10 msec.
	8: increment integration time for CCD camera by 10 msec.
	F: move chopper along "z" by +10 counts.
	f: move chopper along "z" by -10 counts.
        >: move chopper along "x" by +10 counts.
        <: move chopper along "x" by -10 counts.
        ^: move chopper along "y" by +10 counts.
        6: move chopper along "y" by -10 counts.
        ~: start chopping in ON-OFF mode for synchronous detection.
        $: start chopping in OFF-ON-OFF mode for synchronous detection.
	|: stop chopping and synchronous detection.
       
	The first argument inputs the source-name and the second is
	an integer 0 or 1 that sets the PMAC communication flag to 
	disabled or enabled. If this flag is disabled, the program
	does not actually drive the antenna, but updates the 
	coordinates on the display for simulation of tracking. This 
	is useful for debugging, as well as to check the azimuth 
	and elevation coordinates of a given source at the present
	time.

	There are software position limits at 9 degrees and 80
	degrees elevation. The program reads the weather station for
 	on-line atmospheric refraction correction. The weather
	parameters are checked for values within reasonable limits, 
	to prevent an unusually large elevation offset due to a wrong 
	refraction correction.

OPTIONS
	
	To be implemented: 
	1) Input mapping parameters through a user-interface. 
	2) RA-DEC offsets/mapping. 
	3) On-line tiltmeter corrections (presently, the program reads 
	   and displays tiltmeter readings but does not apply
	   corrections).

KNOWN BUGS

	Needs better error-trapping, particularly from communications
	with PMAC. For example, track does not work if PMAC is being
	talked to, through serial port (laptop running PE3).

	Proper motion corrections are currently disabled.

	Needs to be executed at priority higher than 15.


EXAMPLE

	track moon 1 radio
	track Saturn 1 radio
	track alp_ori 0 optical
	track sao17074 1 optical

ENVIRONMENT

	Since the program uses the curses library, it is recommended
	that the terminal be set to vt100 or xterms mode. (rlogin 
	from an xterm on the sun, or use the command "set term = xterms".)
	The program requires the JPL ephemeris file de200_1980_2025.bsp
	and leapseconds.ker file to be in the same area as the
	executable: $SMALOCAL/bin. The source catalog is in the
	form of an ascii file called "sma_catalog".
	($SMALOCAL=/usr/home/accn/local/sma/bin on accn).

RESPONSIBLE
		
	Nimesh A. Patel
	npatel@cfa.harvard.edu
	617 496 7649
	617 496 7626

ACKNOWLEDGMENTS

	The author is immensely grateful to Bob Wilson, Paul Peterson, 
	Richard Hebert, Chuck Acton (JPL), Wilson Hoffman (BIMA), 
	T.K. Sridharan, Masao Saito and Tony Stark for their help.