MEF to SDF conversion
Converting from WSA MEFs
to Starlink SDFs
Downloaded image files from the WSA are currently Rice-compressed
Multiextension FITS files,
in which four extensions correspond to the four WFCAM detectors. The
file name format is typically w<date>_<num>_sf_st.fit.
This page shows how to (i) reverse the Rice compression to get
an uncompressed MEF, and (ii) how to then convert into Starlink SDF
First, make sure you have enough disk space (because a single 5-point
jitter with 2x2 microstepping will, when uncompressed, weigh in at more
than 130 Mbyte per camera).
Get and install the imcopy
to on the WSA site,
The conversion from compressed MEF into SDFs for the individual cameras
is a two-step process. Undo the Rice compression and extract the
individual camera images as follows:
then run up the Starlink conversion routines and use
fits2ndf to effect the conversion:
fits2ndf in='temp.fit' out='x'
and so on.
Starlink files w.sdf, x.sdf, etc. are then the individual camera