fSolar leap years

[rs028]

The year is 366 days long during leap years. This affects the calculation of the Day Angle in fSolar().

[rs028]

Also, the output of the function fails for:

fSolar(df1$Lat, df1$Long, chron("03/16/10", "08:00:00"))

[rs028]

Need to add input validation of latitude and longitude.