NAME: rdastfc PURPOSE: Read an astrometry fit coefficient file. DESCRIPTION: CATEGORY: File I/O CALLING SEQUENCE: rdastfc,file,ffn,ftype,xc,yc,prot,renormfac,cra,cdec,photzp, $ terms,coeffarr,ncoeffs,nlines INPUTS: file - Input file name to be read. OPTIONAL INPUT PARAMETERS: KEYWORD INPUT PARAMETERS: FNCENTERS - File with image centers. (Default=centers.dat) OUTPUTS: Each of these ouputs are vectors or arrays. The length of the vectors or the number of rows is equal to the number of fit coefficient sets in the file. For arrays, the dimensions are [nlines,10] ffn - File name for this fit. ftype - Type of fit (eta or xi) xc - X center of array yc - Y center of array prot - Pre-rotation of raw coordinates (degrees) renormfac- Renormalization factor used for solution. If not known it will be set to -1 cra - Center right acension (radians) cdec - Center declination (radians) photzp - Photometric zero-point for this image. If the value is 99.0 the zero point has not been determined. This will allow you to later compute a real magnitude from instrumental magnitudes on the frame. terms - Term names that are used (see astterms.pro for more information). string vector size is [ncoeffs] coeffarr - Array of astrometric fit coefficients (see astterms.pro) array size is [nlines,ncoeffs] ncoeffs - Number of fitted coefficients (scalar) nlines - Number of coefficients read from file (scalar). KEYWORD OUTPUT PARAMETERS: VERSION - Version tag of file that was read. ERROR - Flag, set if error found during read. COMMON BLOCKS: SIDE EFFECTS: RESTRICTIONS: All of the solutions in the file must have the same number of terms. PROCEDURE: The solution is a two-step conversion. You start with raw coordinates that typically relate to the original position in the native coordinate system for the device. The first transformation step is to convert to another system related to the first by a translation and rotation. e.g. xp = ( (x-xc)*cos(prot) + (y-yc)*sin(prot) ) / renormfac yp = ( -(x-xc)*sin(prot) + (y-yc)*cos(prot) ) / renormfac The astrometric transformation then maps xp,yp to ra,dec. MODIFICATION HISTORY: 1999/04/15, Written by Marc W. Buie, Lowell Observatory 2000/01/19, MWB, added version 1.1 support (now includes photzp) 2002/04/09, MWB, changed from Str_Sep to strsplit 2005/06/28, MWB, fixed bug when reading an empty file. 2009/08/04, MWB, added prot and renormfac variables thus changing the calling sequence (sorry) 2009/12/01, MWB, moved up to version 1.3, calling sequence slightly different again. (terms was flagarr, some returned values have a smaller rank). Added ERROR output.