Opened 18 years ago
Closed 17 years ago
#4 closed defect (fixed)
Incorrect assigning of velocity units from fits files produced from Livedata/gridzilla
Reported by: | Owned by: | Matthew Whiting | |
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Priority: | normal | Milestone: | |
Component: | FITS reader | Version: | |
Severity: | normal | Keywords: | |
Cc: | korinnem@… |
Description
I believe I'm using version 1.05 (will be updated to the most recent version shortly, hopefully).
I am using data from the Parkes 6 GHz multibeam, which is constructed into image cubes in Livedata and Gridzilla (AIPS++ Version 1.9 Build 1041). Karma didn't seen to read the velocity units from Gridzilla if I used the vrad parameter to assign the velocity units, so I've been using the AIPS compatible version of velocity (velo-xxx in Gridzilla) instead as Karma does read it.
However, Duchamp does not seem able to detect the velocity keywords from the fits file:
Error: <fixUnits>: WCSUNITS Error, Code=10: Non-conformant unit specifications. Tried to get conversion from " " to km/s. :setting coordinates to 'xx' for clarity.
In the FITS header, for the AIPS version of velocity, that does not get picked up by Duchamp we have:
CTYPE3='VELO-LSR'
If I use VRAD (that for some reason is not being picked up by Karma) CTYPE3='VRAD'
and Duchamp can pick up the velocity units and convert accordingly.
I had found that a temporary fix seems to be adding the keyword: CUNIT3='m/s'
to the header of files with the AIPS definition, but I don't know whether this could cause problems elsewhere or whether I should be using a different keyword or whether anybody else is having a similar problem.
Change History (3)
comment:1 Changed 17 years ago by
Component: | component1 → FITS reader |
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Owner: | set to Matthew Whiting |
Status: | new → assigned |
comment:2 Changed 17 years ago by
comment:3 Changed 17 years ago by
Resolution: | → fixed |
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Status: | assigned → closed |
Resolving this as 'fixed' -- should have been done earlier!
I think I know how this is coming about, but I need the data to be able to reproduce the problem.
Could you provide me with the FITS file (or even just the full header)?