Wootten, Webster, Radford, Morita, Butler, Conway, Guilloteau, Yun, Woody
Minutes 18 December 2001 ALMA Configuration Teleconference
John gave a report on the visit to the site just concluded. He had perfected his technique, loading waypoints etc into the GPS before embarking to high altitude and exploring along the fingers of Chajnantor. His impression was that in general the mask is conservative and that there is good access on ridges. Some things below the resolution of the mask could prove difficult for configuration construction.
Eshway thought the area fine for building roads, with clearing of rocky bits, which could signal bedrock near the surface. Along the fingers, the going gets steeper away from the site with a rock wall presenting a natural barrier finally several km down the fingers. The country north from center is good. ENE is also pretty good but poorly explored. In a broad quebrada to east of the center Boone and Conway have placed telescopes; a poor place. SSE of center the land gets cut by quebradas and rises; this area needs more exploration. Conway and Webster put scopes on the ridge to the SE some of which were OK and some not. Webster noted the ridge was mask-forbidden; to use it would be liberating.
Discussion turned to how to better characterize the site. Radford proposed low altitude photos but a ground survey would be needed to tie them down, an estimate will be obtained (Eschway?). Woody noted that an aerial survey was used for the CARMA site, $30K 10mi x 10mi to 3m x .5m the expense being in ground control (50%) and digitization (50%). It was agreed that photos of the large area with control and digitization would be needed.
Conway reported traveling clockwise around Chascon visiting Webster and Boone pads. Some of the chosen sites looked impossible when visited. Conway's design, which was to precede the larger design according to the PDR, with a hybrid connecting it to the 14km array, centers to the NE of center. Webster's design, which does not mesh with previous designs for the compact array from Kogan, or with Conway's, tends to center more to the SW, as does Boone's. Hence we have no complete documented design in accord with what was sought at the PDR.
Guilloteau noted the convenience of Boone's array location table, with pad positions and 1 and 0 in columns indicating whether each position is used in a certain 'configuration'. He will attempt to do some simulations despite a busy schedule and trip to Chile.
Butler noted that it had been very instructive to have Eshway along, but that an iterative process will involve the location of the main access road to the OSF.
It was agreed that documents in support of the PDR should be in place
by 9 January to be discussed at a final telecon before the face to face
meeting 24-25 January at the AOC in Socorro.
Next Meeting 15 Jan at 1445