R: Convert astronomical angle in degrees to hours, minutes and...

angle2hms {oce} | R Documentation

## Convert astronomical angle in degrees to hours, minutes and seconds

### Description

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 11h40m48s.10 for the value used in the “Examples”; see Chapter 1 of Meeus (1991) for more on angle calculation and representation.

### Usage

    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.

### Author(s)

Dan Kelley

### References

- Meeus, Jean. Astronomical Algorithms. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1991.

### See Also

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

[Package oce version 1.7-2 Index]