The best places for the most compact ALMA configuration (*not* the ACA - or the array of smaller dishes - although it might be colocated with it) are extended areas of smooth and flat terrain. I've written a memo on finding these places, which is here .
The mask includes the constraints that a valid antenna location cannot be shadowed by more than 25 degrees in any direction, and cannot be shadowed by more than 15 degrees to the north (defined as within 30 degrees of true north), that the location must be interior to the science preserve boundary by more than 150 meters, that the location must be further than 100 meters from both pipelines, that the location cannot be to the northeast of the Jama highway, and that the location cannot have local tilt greater than 5 degrees.
Click here for an ALMA memo describing the construction of the mask.
The FITS files supplied below are simple masks with 1's where antennas can be placed, and 0's where they cannot.
Click here for a plot (gzipped PostScript - 353 kB) of the mask. In this plot, red locations are those where antennas are not allowed; contours are topography - thick lines are at 100 m intervals, thin lines at 50 m intervals; the purple star is the recommended (from the final report of the configuration PDR review committee ) location for the most compact ALMA configuration (see also my memo on that topic ); green lines are the gas pipelines; blue squares are the pipeline crossing locations; pink circle is the gas tap location.
Shift-click here to ftp the gzip'ed FITS file of the antenna location mask.
Last Modified on April 19, 2001
Bryan Butler (bbutler@nrao.edu)