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So within 2 airmasses we can get to 3/4 of the entire sky. A six-band, annual 3pi survey would require 6*3222 = 19K visits. At 50 seconds per visit, this is essentially 16K minutes ~ 270 hours = 30 nights per year. But of course it's only the marginal investment that should count.
Airmass vs. HA and dec:
Cadence, coverage, and passband trades.
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