NAME

tadiodepos -- Find a target acquisition image on the main diode array.

USAGE

tadiodepos input table tabstat aperture

DESCRIPTION

This task locates the diode position of a target acquisition image viewed with the main diode array. The left and right edges of the image are located as the position where the flux is 1/2 the maximum flux. The center is then computed as the average of the two edge positions. The centroid and Full-Width- Half-Maximum (computed as the difference between edge positions) are also computed. Output units are in diodes.

PARAMETERS

input [file name]

Name of the input file containing the target acquisition image viewed with the main diode array. The length of the data must be 500, 1000, or 2000 data points--corresponding to no-substepping, half-stepping, and quarter-stepping, respectively.

table [file name]

Name of the output table produced by tadiodepos; it will have the following columns:

     'CARPOS'     - Carrousel position (integer).
     'X_CENTER'   - Center position of the image (double).
     'X_CENTROID' - Centroid of the image (double).
     'FWHM'       - Full-width-half-max of the image (double).
     'PEAK'       - Peak counts of the image (double).

tabstat = "write" [string, allowed values: write | append]

Method used to store the output results. If "write" is specified, a new table will be created having the file name specified by table. If "append" is specified then the data produced by tadiodepos is appended to the end of an existing data table; in this case the input data must be for the same target acquisition mirror mode as the previous entries in the table.

aperture = "lsa" [string, allowed values: lsa | ssa | sc| sc2]

Three character name of the aperture being located. If the output table status is "append", then the aperture name in the input image is checked for consistency with the aperture name stored in the header of the output table.

(d= 0) [integer, min=0, max=500]

The first diode range in which to search for the peak. If d1 = 0, then the entire observation is searched. This parameter is useful if multiple apertures are observed and the position of a weaker peak is desired.

(d= 0) [integer, min=0, max=500]

The last diode in the range in which to search for the peak. If d1 or d2 are not specified (i.e., they are set to 0), the entire diode array is searched.

EXAMPLES

1. Locate the brightest aperture, "SSA", in the observation image n1data.

	cl> tadiodepos.aperture = "SSA"
	cl> tadiodepos n1data

2. Now locate the dimmer "SC1" aperture in the same data file. Start looking at a diode position 10 diodes to the right of the previously found center for the SSA aperture. Append the results to an existing table diodepos.tab.

	cl> tadiodepos.d1=320
	cl> tadiodepos.d2=350
	cl> tadiodepos.aperture = "SC1"
	cl> tadiodepos n1data diodepos append

BUGS

REFERENCES

HELP

For assistance using this or any other tasks, please contact help@stsci.edu or call the help desk at 410-338-1082.

SEE ALSO

tacarrousel