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spiralmap --Construct GHRS spiral-search map.
spiralmap input output
The GHRS has the capability of mapping a 10 x 10 arcsecond area of the sky as seen through the 2 x 2 arcsecond large science aperture. This is done by performing a "spiral search" consisting of twenty-five maps of the large science aperture (LSA) using one of the focus diodes. The spatial resolution of the maps is 0.125 arcseconds---the size of the focus diodes. The spiral search may be also be carried out for a 6 x 6 arcsecond area of the sky consisting of nine individual maps. While the individual maps are 22 x 22 pixels in size, only a 16 x 16 pixel piece of this maps the LSA. The individual maps also cover overlapping areas of the sky. Currently, a map is displaced 1.75 arcseconds (in either the X or Y direction, or both) from the position of the previous map resulting in an overlap of 0.25 arcseconds, or about two pixels.
This task assembles the individual maps into a single map suitable for display by trimming the individual maps to 16 x 16 pixels (except for those edges that end up as an outer edge in the composite map) and averaging the overlapping regions of two pixels. spiralmap also produces a mosaic of the raw maps; this map is placed in the tmp$ directory with a temporary name that looks something like ssmapXXXXX.
- input [file name]
- The image name of the GHRS observation.
- output [file name]
- The image name of the map built up from the individual maps.
- (left = 3) [integer]
- The number of pixels to trim off the left side of the individual maps.
- (right = 3) [integer]
- The number of pixels to trim off the right side of the individual maps.
- (top = 3) [integer]
- The number of pixels to trim off the top of the individual maps.
- (bottom = 3) [integer]
- The number of pixels to trim off the bottom of the individual maps.
- (overlap = 2) [integer]
- The number of pixels to overlap adjacent individual maps.
1. Construct a spiral search map from observation z00xh903r.
hr> spiralmap z00xh903r.d0h map.hhh
For assistance using this or any other tasks, please contact firstname.lastname@example.org or call the help desk at 410-338-1082.