Open astrofle opened 7 months ago
We should come to a general consensus about how metadata should be treated when averaging spectra.
When averaging integrations or ScanMixin derivatives, the header values of the resultant Spectrum should contain averages of [most] numeric values in the individual integrations/Scans.
The exceptions are:
Primary header variables such as TELESCOP, SITELONG, etc could be made into columns in the SDFITS table, though since they are constant it is unlikely that anyone would want to use them for selection. It makes more sense to have an user-level accessor in SDFITSLoad for the primary header. Also the primary header values would be added to spectral metadata (averaged or not) in Spectrum.make_spectrum()
TUNIT7 can take on whatever the flux unit is of the spectrum, but perhaps is better to be replaced with the more conventional FITS keyword BUNIT.
It is unclear what the purpose of LASTON and LASTOFF are; the description simply says “LAST ON/OFF for position switching.’ We can update them I guess, but that info would also be in to-be-implemented command logging.
INT is integration number (intnum) which GBTIDL allows selection on. A series of rows in SDFITS that are all part of the same integration (e.g., cal on, cal on, pols, sig, ref) all share the same integration number. Peter and I discussed this yesterday in a different context and agreed intnum was important to keep as a concept. Likely implementation would be that it is created as an SDFITS column on GBTFITSLoad instantiation, e.g., everything with the same OBSDATE gets the same intnum. I consider this a separate issue.
Split into EXPOSURE and DURATION as high priority, the rest medium priority.
getps
does not update some of the metadata of the result after usingtimeaverage
on the result.Example:
The following columns are not being updated:
The following columns are updated, but do not agree with
GBTIDL
:GBTIDL
keeps this one equal to 0 -- This difference should be fine as long asdysh
is self consistent and thegbtgridder
understands what this means if needed.The following columns were not found in
dysh
but are inGBTIDL
:The columns below are keywords in the header, not sure why
GBTIDL
makes them columns nowThis one I don't think we care about