Estimating Angstrom-Prescott Coefficients for India and Developing a Correlation between Sunshine Hours and Global Solar Radiation for India

Table 1

Estimated angles of declination for various months in a year.

Month	d for ith day of the month	For the average day of the month
		Date	d, day of the year	𝛿, angle of declination
January	𝑖	17	17	–20.9
February	31+𝑖	16	47	–13.0
March	59+𝑖	16	75	–2.4
April	90+𝑖	15	105	9.4
May	120+𝑖	15	135	18.8
June	151+𝑖	11	162	23.1
July	181+𝑖	17	198	21.2
August	212+𝑖	16	228	13.5
September	243+𝑖	15	258	2.2
October	273+𝑖	15	288	–9.6
November	304+𝑖	14	318	–18.9
December	334+𝑖	10	344	–23.0