Download or view mithengereverse2.frink in plain text format
use sun.frink;
use mithengecorridor.frink;
// Program to reverse-engineer MIThenge observation by Ken Olum on 2005-01-31:
// "At 4:51:00 I observed that the right limb of the sun lay on a line
// from my eye at roughly 38 inches (sorry for the barbaric units) inward
// from the left wall of the corridor to the right edge of the doorframe.
// I think the corridor is 13 feet wide at that point and the doorway is
// centered and 5 feet wide."
//
// Ken provided better measurements of these points later. See:
// See diagram at http://cosmos.phy.tufts.edu/~kdo/corridor.jpg
date = # 2005-01-31 04:51:00 PM Eastern #
println[date -> Eastern]
// Calculate the sun radius at this time.
sunRadius = sunRadiusAngle[date]
println["Sun radius is " + (sunRadius -> "degrees")]
// Temperature and pressure figures are as measured in Cambridge for this
// date and time.
[sunAzimuth, sunAltitude] = refractedSunAzimuthAltitude[date, lat, long, F[29], 30.42 inHg]
// Convert Meeus azimuth conventions to normal conventions.
sunAzimuth = (sunAzimuth + 180 degrees) mod circle
println["Sun center azimuth is " + (sunAzimuth -> "degrees")]
// Horizontal distance from right edge of doorframe
h = (9 feet + 11 inches) - (38 inches) - (2 feet + 11 inches)
// Distance from doorway in corridor on 3rd floor
d = 279 feet + 89 feet
// The angle added to the centerline of the corridor
angleOffset = arctan[h,d]
println["Angle offset is " + (angleOffset -> "degrees")]
// Azimuth of the right-hand-limb of the sun
sunRight = sunAzimuth + sunRadius
println["Right limb of sun is " + (sunRight -> "degrees")]
// Correct angle of the corridor
corrAzimuth = sunRight - angleOffset
println["Corridor azimuth is " + (corrAzimuth -> "degrees")]
Download or view mithengereverse2.frink in plain text format
This is a program written in the programming language Frink.
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Alan Eliasen was born 20217 days, 23 hours, 29 minutes ago.