faber

faber

stlocal.testfgs

faber

NAME · USAGE · DESCRIPTION · PARAMETERS · EXAMPLES · BUGS · SEE_ALSO

NAME

faber -- Add or remove aberration from a data table.

Data tables are searched, row by row, for lines in which the FRAME column contains any valid frame type except E (equatorial coordinates). When a valid frame type is found, the X, Y, and associated covariances are read from the table. After each column is read, its value is set to INDEF so that transformation errors will be flagged.

Aberrations are corrected according to the following conditions:


	if(current_aberration_status == 'N') {		# none
	    position_vector = aberrate(position_vector, velocity_vector)
	}
	if(desired_aberration_status == 'none') {
	    negate the velocity vector
	    position_vector = aberrate(position_vector, velocity_vector)
	}
	if(current_aberration_status == 'D') {		# differential
	    negate the velocity vector
	    position_vector = differential(position_vector, velocity_vector)
	}
	if(desired_aberration_status == 'differential') {
	    position_vector = differentiaL(position_vector, velocity_vector)
	}

Aberrate is a function that corrects absolute aberrations; differential is a function that corrects differential aberrations. By tracing through this algorithm from any of the possible aberration states, it should be clear what steps are taken to complete the transformation.

After a successful transformation, the ABER column is set to the current state and new position information is written to the table. Velocity information must be in kilometers per second, with the value of c (speed of light) defined as 299792.458 km/s.

'Faber' uses the following columns:

	INPUT				OUTPUT
	-----				------
	X				X
	Y				Y
	FRAME				FRAME
	ABER				ABER
	X_VEL,Y_VEL,Z_VEL		Q1,Q2,Q3,Q4
	Q1, Q2, Q3, Q4

PARAMETERS

intable [file name template]: This is either the file name for an individual table or a list of file names for a group of data tables upon which faber will operate in-place.

new_aber = "none" [string, allowed values: none | absolute | differential]: Desired aberration state. Are final coordinates to be affected by absolute aberrations, differential aberrations, or none?

(outtable) [file name template]: Not yet implemented.

(new_table = no) [boolean]: Create a new output table to prevent overwriting the current table? Not yet implemented.

(verbose = yes) [boolean]: Print the transformed coordinates to the terminal screen?

EXAMPLES

1. Remove differential aberrations from a data set.

	fg> faber intable differential

2. Remove absolute aberrations from a data set.

	fg> faber intable absolute

3. Process all tables that have the suffix .tab.

	fg> faber *.tab

NAME

USAGE

DESCRIPTION

PARAMETERS

EXAMPLES

BUGS

SEE ALSO