Syntax

An ANT can be given as a single string (literal/pattern/regular expression), single integer ID, a range of integer IDs or a comma separated list of integers. For VLA-specific reasons (see Section 3.2), only for antenna specifications, integers are first converted to strings and matched against the antenna names. E.g.

• VLA:N1 corresponds to antenna named "VLA:N1".
• 1,2,3 corresponds to antennas named "1", "2" and "3".
• 1$\sim$3 corresponds to antennas named "1", "2" and "3".
• VLA:N* corresponds to all antennas who's name starts with "VLA:N".

A baseline specification consists of an ANT, an ANT followed by an ampersand or a pair of antenna specifications separated by ampersand. Formally, baseline specification is of the form ANT[&ANT] (where the part in square brackets is optional).

An atomic ANT selects all baselines containing all the antennas in ANT. ANT& selects only baselines between the list of antennas in the antenna specification. ANT1&ANT2 selects baselines between antennas in ANT1 and ANT2 only. E.g.

• baseline=1,2,3 selects baseline between antennas 1, 2 and 3 and all other antennas.
• baseline=1,2,3& selects baseline between antennas 1,2 and 3 only.
• baseline=1,2,3 & 4,5,6 selects baselines between antennas 1,2,3 and 4,5,6.

Following are more examples of baseline specification using ranges and names:

• baseline=1$\sim$3 same as baseline=1,2,3
• baseline=1$\sim$3& same as baseline=1,2,3&
• baseline=1$\sim$3 & 4$\sim$5 same as baseline=1,2,3&4,5,6
• baseline=VLA:N* & VLA:E* selects all baselines between antennas with names starting with "VLA:N" and "VLA:E".

The full baseline selection expression is any of the examples shown above or a semi-colon-separated list of baseline specifications. E.g.

• baseline=1$\sim$3& ; 4$\sim$5&10$\sim$15 ; VLA:N* & VLA:E*

with each elements of the semi-colon separated list being interpreted as explained above.