Short spacings (

Let's note the diameter of the single-dish antenna (m for the
IRAM-30m telescope) used to produce the short-spacing information and
the diameter of the interferometer antennas (m for PdBI). We
already mentioned that a multiplicative interferometer filters out all the
spatial frequencies smaller than meters. When this information is
needed to get reliable results, the source should also be observed with a
single-dish antenna to produce the missing information. The single-dish
antenna furnishes information about all spatial frequencies up to
meters (but this information is weighted by the single-dish beam shape,
*i.e.* high frequencies are measured with a worse signal-to-noise ratio than
low frequencies). To recover all the information at spatial frequencies
smaller than meters, the diameter of single-dish antenna must be
larger or equal to the diameter of the interferometer antennae: .

- Algorithms to merge single-dish and interferometer information

- Practical considerations

Gildas manager 2018-09-24