Horizontal sundial calculations: Difference between revisions

<lang haskell>module Rosetta.HorSunDial where

roundDec :: Int -> Double -> Double

roundDec d = (/10.0^d). fromIntegral. round. (*10.0^d)

radToDegr = ((180/pi)*)

degrToRad = ((pi/180)*)

let lat = -4.95

long = -150.5

sinOfLat = sin $ degrToRad lat

diff = legalMerid - long

putStrLn $ "Latitude " ++ show lat

putStrLn $ "Longitude " ++ show long

putStrLn $ "Legal meridian " ++ show legalMerid

putStrLn $ "Sine of latitude " ++ show (roundDec 6 sinOfLat)

putStrLn $ "Diff longitude " ++ show (-diff)

putStrLn "hour sun hour angle dial hour line angle"

mapM_ (\h ->

let sha = diff + 15*h

dhla = radToDegr . atan. (sinOfLat *). tan $ degrToRad sha

in putStrLn $ take 7 (show h ++ repeat ' ')

++ take 16 (show (roundDec 3 sha) ++ repeat ' ' )

++ " " ++ show (roundDec 3 dhla)

) [-6,-5..6]</lang>