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Re: Standard Astronomical Refraction Tables [-1°,0°]
From: Lars Bergman
Date: 2024 Jun 30, 06:27 -0700
From: Lars Bergman
Date: 2024 Jun 30, 06:27 -0700
Kermit,
I have an excel file made at least two years ago giving refraction for negative altitudes. It might be older though. I have a faint memory that it is based on a post by Frank, but I am not sure. Anyway, it calculates
R = exp( 3.537 + 0.369 h + 0.051 h2 )
where R is refraction in minutes of arc, h is the apparent altitude in degrees. Valid for -3°<h<0° at a temperature of 10°C and pressure 1010 hPa. It gives slightly larger magnitude of the refraction than both your tables.
Lars
