Time of sunrise and sunset at Singapore and Penang during the year
This short note by H. Marriott (1918) presents a chart of sunrise and sunset times at Singapore and Penang throughout the year, accompanied by a brief explanation of the factors affecting day length at these low latitudes.
The chart uses a horizontal scale of five days per space and a vertical scale of one minute per space, with a dotted curve indicating the equation of time. Marriott notes that Singapore’s clocks run 4 minutes 40 seconds ahead of true local time due to the use of the 105°E standard meridian rather than the local longitude of 103°50′, while Penang’s corresponding offset is 18 minutes 36 seconds (p. 101). The difference between the longest and shortest days is only about 9 minutes at Singapore but 36½ minutes at Penang, where the effect of latitude is sufficient to make July evenings longer than February ones, whereas at Singapore the longest evenings occur in February and are caused entirely by the equation of time (p. 101). The calculated times are Singapore standard times for the centre of the sun’s disc on the horizon at sea level, with allowance made for refraction (p. 101).