The purpose of angle2hms is to facilitate comparison of rightAscension angles computed by sunAngle() and moonAngle() with angles reported in astronomical sources and software, which often employ an hour-minute-second notation. In that notation, decimal hour is computed as 24/360 times the angle in degrees, and from that decimal hour are compute integer hour and minute values, plus a decimal second value. It is common in the astronomical literature to use strings to represent the results, e.g. with $$11^h40^m48^s.10$$ for the value used in the “Examples”; see Chapter 1 of Meeuse (1991) for more on angle calculation and representation.

angle2hms(angle)

Arguments

angle numerical value giving an angle in degrees

Value

angle2hms returns a list containing values time (a numerical value for decimal hour, between 0 and 24), hour, minute, and second (the last of which may have a fractional part), and string, a character value indicates the time in hour-minute-second notation, with the second part to two decimal places and intervening h, m and s characters between the units.

References

• Meeus, Jean, 1991. Astronomical algorithms. Willmann-Bell, Richmond VA, USA. 429 pages.

Other things related to astronomy: eclipticalToEquatorial(), equatorialToLocalHorizontal(), julianCenturyAnomaly(), julianDay(), moonAngle(), siderealTime(), sunAngle(), sunDeclinationRightAscension()

Examples

# A randomly-chosen example on page 99 of Meeus (1991).
angle2hms(177.74208) # string component 11h50m58s.10#> $hourDecimal #> [1] 11.84947 #> #>$hour
#> [1] 11
#>
#> $minute #> [1] 50 #> #>$second
#> [1] 58.0992
#>
#> \$string
#> [1] "11h50m58s.10"
#>