# # Differential Photometry for the Cepheid star # # Before you start: # # copy all fits images of the times series into a working directory # make a file with the names of all fits images, e.g. "ls -1 ceph* > imlist" # make a file with the julian dates, e.g. "cp imlist juliandate" and then remove the unnecessary bits # make a file called 'starcoor' with the xy position of the star you want to do photometry. Cepheid is at xy= 101 101 # make a file called 'refstarcoor' with the xy position of a suitable reference star for differential phot, eg xy=103,172.5 # # Then run this series of commands in iraf with "cl < procedure" # # Cleaning up before starting delete ceph*.mag.* delete temp delete mergemag delete finalphot qphot '@imlist' 4 5 5 3.5 coord=starcoor inter- tmerge ceph*.mag.1 mergemag 'append' allcols- tbltype=text tproject mergemag temp "1,29,30" #extract name of image, mag and mag error from target star delete temp2 delete mergemag qphot '@imlist' 4 5 5 3.5 coord=refstarcoor inter- tmerge ceph*.mag.2 mergemag 'append' allcols- tbltype=text tproject mergemag temp2 "1,29,30" #extract name of image, mag and mag error from reference star delete result delete results delete results2 tmerge 'temp,temp2' result 'merge' allcols+ tbltype=text tdump result cdfile="" pfile="" datafile="results" tmerge 'juliandate,results' finalphot 'merge' allcols+ tbltype=text tcalc "finalphot" "magdiff" "c3-c6" tstat finalphot 8 axispar.wl=90.3 axispar.wr=95.0 axispar.wb=tstat.median-3*tstat.stddev #0.95*tstat.vmin axispar.wt=tstat.median+3*tstat.stddev #1.05*tstat.vmax axispar.xlabel='Julian Date' axispar.ylabel='Delta mag' sgraph "finalphot c1 magdiff" errcol=4 pointmo+ delete ceph*.mag.* delete temp delete temp2 delete mergemag delete result delete results