The PR folks have asked about changes to the brochure, to have a new version ready for the IAU. This presents an opportunity to present a new set of sensitivities. I took your email of 12 June as a guide for this, as I think we pretty much agree, with the material in the Memo Bryan and I wrote as a basic approach. Changes (besides using 6hnu/k mm and 10 hnu/k submm rather that the admittedly optimistic 3 hnu/k; only band center freqs in the tables here) include: Opacity percentiles (your point B1): I looked at: http://www.tuc.nrao.edu/mma/sites/Chajnantor/data.c.html where the mm wavelength 75% quartile is .117 mm pwv and the 25% quartile is .037 mm pwv. According to Bryan Butler's atmospheric models: 1 - 75th percentile opacity at 225 GHz of 0.117 (it's not really 230 GHz...) and surface temperature of 3.2 C implies about 3.2 mm PWV. so, taking a zenith angle of 40 deg, i get the following opacities: freq (GHz) opacity ---------- ------- 35 0.018 90 0.038 140 0.062 225 0.151 2 - 25th percentile opacity at 225 GHz of 0.037 and surface temperature of -7.6 C implies about 0.85 mm PWV. again taking a zenith angle of 40 deg, i get the following opacities: freq (GHz) opacity ---------- ------- 35 0.015 90 0.025 140 0.025 225 0.047 Forward efficiency: I have adopted your approach of a quadratic decrease from 95% at 31 GHz to 90% at 950 GHz. Aperture efficiency: I used 20 microns rather than 25, since that is the current telescope spec. I obtain (big table--stretch your margins!) Freq. Dependent Quantities Point Pt. SourPt. Sour Source rms(mJy)rms(mJy) Freq. Lam(mm) Trx(k) t Ant.Effic. e RMS(mJy)1 km/s 25 km/s 35 8.556 20.8 0.014 1.015 21.12 3.83 13.41 38.36 0.00 0.80 0.95 0.020 5.147 1.03 N. B. 2.3 mm pwv for mm) 90 3.331 29.9 0.017 1.019 30.47 4.67 13.56 48.70 0.01 0.80 0.95 0.027 4.4 0.89 140 2.141 44.3 0.020 1.022 45.29 5.50 13.78 64.56 0.01 0.79 0.95 0.039 5.1 1.01 230 1.303 70.2 0.117 1.136 79.8 33.89 15.86 129.5 0.06 0.75 0.95 0.071 7.2 1.44 345 0.869 136.5 0.134 1.157 157.91 39.13 17.28 214.32 0.08 0.74 0.94 0.120 9.951 1.99 N. B. .71 mm pwv for submm) 409 0.733 161.0 0.264 1.332 214.42 82.29 20.83 317.55 0.12 0.71 0.94 0.184 14.009 2.8 650 0.461 316.0 0.854 2.528 798.81 373.65 48.99 1221.45 0.30 0.59 0.93 0.849 51.141 10.23 850 0.353 412.0 0.85 2.528 1041.49 366.94 60.09 1468.52 0.51 0.48 0.91 1.260 66.387 13.28 1500 0.200 1803.8 3.34 37.688 67982. 7989.17 1738.31 77709. 1.58 0.16 0.83 195.076 7737.0 1547.42 Submm taus Based on Matsushita et al 1999 Stephane's numbers: Nu 35 Tsys 32.3 Tau 0.013 Nu 90 Tsys 55.9 Tau 0.033 Nu 140 Tsys 77.6 Tau 0.049 Nu 230 Tsys 134.8 Tau 0.116 Nu 345 Tsys 251.4 Tau 0.123 Nu 409 Tsys 348.4 Tau 0.222 Nu 650 Tsys 917.6 Tau 0.653 Nu 850 Tsys 1.012 Tau 0.582