File with input source positions. Must contain columns RA and Dec., either internally or through use of datamodel column filter. RA and Dec. columns must be in decimal-degree (i.e., not sexagesimal) format. At least 3 input sources must be found to be a match for 3 reference sources. residfac parameter will only be useful if columns RA_err and Dec_err are present in infile and refsrcfile.

File of reference source positions. Must contain columns RA and Dec., either internally or through use of datamodel column filter. RA and Dec. columns must be in decimal-degree (i.e., not sexagesimal) format. At least 3 input sources must be found to be a match for 3 reference sources. residfac parameter will only be useful if columns RA_err and Dec_err are present in infile and refsrcfile.

If this input file is an asol file, the RA, Dec., and roll columns of each row will be updated and written to the outfile. If this input file is either a fits image or table, the WCS in this file will be updated.

If there are multiple aspect solution files for the observation, all the files may be given as a stack in this parameter; see "ahelp stack" for more information. In this case, a stack of output files containing the same number of elements must be supplied in the outfile parameter.

This file is created when the input file is an aspect solution file. All data are copied from the aspect solution file and the RA, Dec, and roll are modified by values calculated by reproject_aspect. If the input file is not an aspect solution file, outfile must still be specified but is not used and can be blank.

If a stack of aspect solution files is given in the updfile parameter, a stack of output filenames containing the same number of elements must be supplied in this parameter. See "ahelp stack" for more information on working with stacks of files.

The WCS file must contain WCS coordinate transform data with a tangent point near the sources of the infile and refsrcfile. It can be either a fits image file with a "EQPOS" WCS, or a fits table file with "EQPOS" or "EQSRC" WCS. A WCS file must be specified unless a WCS is present in either the input or reference source file. If a wcsfile is provided and a WCS is present in either source file, the WCS from the wcsfile will be used.

Allowable values are either a filename - to send the output to a given file - or one of stdout or STDOUT, which sends the information to the standard output (normally the screen).

Source positions from the two source files can only match each other if they are no farther apart than the value specified as the source match radius. Only a single reference source can be within the source match radius of a input source, and only a single input source can be within the source match radius of a reference source. If multiple sources are found in either case, the source pair is not used to calculate the transform.

After the transform is calculated and initially applied to the input source positions, if the largest source pair position error exceeds the value of residlim, then that pair is eliminated from the transform calculation and the calculation is repeated. This process of eliminating the source pair with the largest residual and repeating the calculation continues until all remaining source pair position errors are less than the residlim value.

Set residlim to 0 to disable this feature and prevent source pairs from being removed based on absolute residual value. Residlim takes precedence over residfac if both are nonzero.

Two different options can be used to eliminate source pairs from the transform calculation when the residual ratio limit factor (residfac) is specified. If residtype is set to 0, residfac is interpreted as an upper limit on the residual-to-source pair position error ratio. Any source pairs with ratios above residfac will be eliminated from the transform calculation. If residtype is set to 1, residfac is interpreted as an upper limit on the average of all ratios. Source pairs with the highest ratios will be incrementally removed from the transform calculation until the average of all ratios drops below residfac.

After the transform is calculated and initially applied to the input source positions, if either the largest residual-to-source pair position error ratio exceeds the value of residfac (when residtype=0), or the average of all ratios exceeds the value of residfac (when residtype = 1) then the source pair with the largest ratio is eliminated from the transform calculation and the calculation is repeated. This process of eliminating a source pair and repeating the calculation continues until the appropriate ratio test is met.

Set residfac to 0 to disable this feature and prevent source pairs from being removed based on the residual-to-source pair position error ratio. Residlim takes precedence over residfac if both are nonzero.

Increasing amounts of debug information are printed to "logfile" as the value of verbose is increased from 0 to 5. Setting verbose=1 shows details of the source pair errors after applying the transform to the input source positions.