Personal tools
You are here: Home / COSMOS / sumspec

sumspec

Back to Programs

sumspec

sumspec combines extracted 1-d or 2-d spectrum files. The output spectra are a straight sum of the input spectra. CR rejection can be applied to 2-d files if there are multiple input files. The output file format is the same as the input format, as described in the documentation for extract-2dspec.


USAGEsumspec -o outfile infiles
INPUTinfiles is a list of input files root names (e.g. ccdnnnn)
OUTPUToutfile is the name of the new file created. It must end in _1spec or _2spec
PARAMETERS
cleanremove cosmic rays?
siglimitCR rejection threshold in units of sigma
bothremove both positive and negative residuals?
iterationsnumber of iterations of cleaning
growrejected region grow width, in pixels


Details:

Unless cosmic ray rejection is requested, sumspec simply sums the intensity values from each file. If the input files contain a second plane with error data, the error values are combined appropriately. If CR rejection is requested (2-d data only), the data are first scaled by exposure time, then summed and data points more than siglimit higher than the mean given zero weight, after which a final sum is made. CR rejection requires input data produced with newer versions of COSMOS which include the exposure time.


For normal (as opposed to nod&shuffle;) data, rejecting only positive deviations (both = 'n') usually works best, and is the only way to CR clean frames when there are only two. Nod&shuffle; data must have the shuffled region subtracted before using sumspec, and then requires that both positive and negative deviations be removed, and a minimum of three frames.


If the grow parameter is set to a non-zero value, a border of additional rejected pixels is added to any region of rejected pixels.


The spectrum files to be summed must match identically: data sampling and object list. To ensure this, the extraction of all spectrum files should start with the same initial map file, created with map-spectra. (The final map files will differ slightly, of course, since each will have been modified using adjust-map and a different comparison arc.)


Back to Programs