Reference Position (Offset)

Up to two reference positions can be specified if this option has been selected in the panel above, but only one of these is currently used. The purpose of this position differs depending on the context. For interferometric SBs it is used to determine the position used for the system temperature measurement - by default it is set to a 2 arcmin in longitude only. Solar SBs use a value of 2 deg. For TP SBs it is also used for the “OFF” position, an area of sky that should be devoid of emission. This is by default set to the edge of the scanning area, but should be replaced with a position known to contain no signal.

The parameters are:

The ALMA OT Team, 2024 May 21