Horizontal sundial calculations: Difference between revisions

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=={{header|Ring}}==

<lang ring>

# Project : Horizontal sundial calculations

# Date : 2017/10/24

# Author : Gal Zsolt (~ CalmoSoft ~)

# Email : <calmosoft@gmail.com>

load "stdlib.ring"

pi = 22/7

decimals(3)

latitude = -4.95

longitude = -150.5

meridian = -150.0

see "enter latitude (degrees): " + latitude + nl

see "enter longitude (degrees): " + longitude + nl

see "enter legal meridian (degrees): " + meridian + nl

see "time " + " sun hour angle" + " dial hour line angle" + nl

for hour = 6 to 18

hra = 15*hour - longitude + meridian - 180

hla = 180/pi*(atan(sin(pi/180*latitude) * tan(pi/180*hra)))

if fabs(hra) > 90

hla = hla + 180 * sign(hra * latitude)

ok

see "" + hour + " " + hra + " " + hla + nl

next

</lang>

Output:

<pre>

enter latitude (degrees): -4.950

enter longitude (degrees): -150.500

enter legal meridian (degrees): -150

time sun hour angle dial hour line angle

6 -89.500 84.607

7 -74.500 17.316

8 -59.500 8.342

9 -44.500 4.850

10 -29.500 2.796

11 -14.500 1.279

12 0.500 -0.043

13 15.500 -1.371

14 30.500 -2.911

15 45.500 -5.021

16 60.500 -8.680

17 75.500 -18.488

18 90.500 -96.224