| Diameter | Beam | Pointing | |
| (300 GHz) | map | mosaic | |
| 8m | 32'' | 3.2'' | 1.1'' |
| 10m | 25'' | 2.5'' | 0.8'' |
| 12m | 21'' | 2.1'' | 0.7'' |
| 15m | 17'' | 1.7'' | 0.6'' |
The pointing needs for the antennas considered for the proposed
LSA/MMA collaboration are summarized in Table 1.
The requirement to point at a tenth of a beam width seems sufficient
for good quality imaging in a field smaller than the primary beam
width. However there is a lot of concern for being able to image
fields larger than one beam width by mosaicing. From the work of
Holdaway ([1997]) it appears that mosaics with high dynamic
range ( 
) require pointing to 1/30th of a beam width, hence
the last column in Table 1. Note however that
anomalous refraction (Holdaway [1997]) limits pointing
accuracy to about 0.5'' for a large fraction of the available
time.
In this memo I try to address the following topics: (i) Will sensitivity allow the pointing be calibrated to such an accuracy, and how frequently? (ii) What is our experience with pointing calibration of the 15m Plateau de Bure antennas?
