Selection by header value

A powerful feature of molly is that spectra can be selected by header attributes. Thus it is possible to read from a file only those spectra with phases between 0 and 0.1 for instance, or with name e.g. "SS Cyg" etc. The header editor in molly allows for the inclusion of an arbitrary set of header items as long as their names are unique for their data type. Thus, one could measure the strength of a spectrum line, dump it out, edit the file to suit the header editor and set a new header parameter representing the strength of the line. One could then average only those spectra with the line having a certain strength or whatever.

It should be noted that not all molly commands apply selection, since for some commands (e.g. adding a series of spectra) it could lead to incompatible numbers of spectra.

Header selection is also a useful of separating out spectra of a particular object. You could do this by name, or to be safe by RA and Dec. You could then write these to a file for later analysis.


Tom Marsh, Warwick.