SHORT_SD_WEIGHT
REAL weight scaling factor for the generated visibilities.
It is a relative scaling factor in the weights compared to a supposedly op-
timal weighting to give the best combined synthesized beam. That optimal
weighting essentially gives the same weight density par unit area in the UV
plane than the shortest baselines measured with the interferometer only.
However, if the single-dish data has not been observed long enough, or has
baselines problems for example, this weight may add noise to the overall
data set, so could be down-weighted.
Default: 1.0
See also SHORT_CHANNELS for other issues about noise estimate.