Download or view mithengereverse4.frink in plain text format
// This is reverse-engineering of Ivan's picture of MIThenge #0900
use sun.frink
use mithengecorridor.frink
// Date from EXIF data
exifdate = #2007-08-27 03:42:27 Eastern#
// The 0903 image was taken of Lenny's GPS receiver, showing true time.
// The (bad) time from exif data
badEXIFdate = #2007-08-27 03:59:00 Eastern#
// The (true) time from GPS
goodGPSdate = #2007-08-27 04:57:54 Eastern#
// This is the offset that has to be *added* to the EXIF dates to get the
// true date
dateOffset = goodGPSdate - badEXIFdate
truedate = exifdate + dateOffset
println["The camera offset is $dateOffset"]
println["The true date was " + (truedate -> Eastern)]
// We don't care all that much about refraction, so the temp/pressure figures
// below may not be accurate but shouldn't matter much.
[moonAzimuth, moonAltitude] = refractedMoonAzimuthAltitude[truedate, lat, long, F[29], 30.42 inHg]
// Convert Meeus azimuth conventions to normal conventions.
moonAzimuth = (moonAzimuth + 180 degrees) mod circle
println["True moon azimuth at this time was " + format[moonAzimuth,"degrees",5]]
println["Approx. altitude at this time was " + format[moonAltitude,"degrees",5]]
latticewidth = 31.5 in
rightOffset = (1.7 cm) * (latticewidth/(7.8 cm))
dist = 465 ft - (16 ft) - (20.5 in)
// The grating is offset to the right of the centerline of the corridor.
grateOffset = (1.5 cm / (11 cm)) latticewidth
println["Grate offset is " + (grateOffset -> "in")]
moonRadius = moonRadiusAngle[truedate]
println["Moon radius is " + format[moonRadius,"degrees", 5]]
println["Moon diameter is " + format[2*moonRadius,"degrees", 5]]
println["Right offset is " + (rightOffset -> "in")]
println["Distance is " + (dist -> ["ft","in"])]
correctionAngle = arctan[rightOffset+grateOffset, dist]
println["Correction angle is " + (correctionAngle -> "degrees")]
trueAzimuth = moonAzimuth - correctionAngle
println["True corridor azimuth is " + format[trueAzimuth,"degrees",3]]
Download or view mithengereverse4.frink in plain text format
This is a program written in the programming language Frink.
For more information, view the Frink
Documentation or see More Sample Frink Programs.
Alan Eliasen was born 19967 days, 0 hours, 53 minutes ago.