date_sollong: Calculation of solar longitude

In MetFns: Analysis of Visual Meteor Data

Description

Calculates solar longitude with respect to the equinox of 2000.0 for given date.

Usage

date_sollong(date,prec=4)

Arguments

date	character vector or factor of length one specifying date, given in "%Y-%m-%d %H:%M:%S" format (UTC timezone).
prec	numeric vector specifying number of decimals of calculated solar longitude (between 2 and 5 decimals). By default, it is equal to 4.

Details

Solar longitude is calculated applying VSOP87 theory, using coefficients from data EarthVSOP87B.

Value

sollong returns solar longitude, numeric vector of length one.

Note

User can specify date without time (i.e. date at midnight) or date with hours and minutes (without seconds).

Author(s)

Kristina Veljkovic

References

Meeus, J. (1998). Astronomical algorithms (Second Edition). Willmann-Bell, Inc., Richmond, Virginia, p. 219.

http://neoprogrammics.com/vsop87

See Also

solar.long,sollong_date

Examples

## calculate solar longitude corresponding to March 7, 2016, at 02:41 UTC
date_sollong(date="2016-03-07 02:41")

Example output

Loading required package: astroFns
Loading required package: lubridate

Attaching package: 'lubridate'

The following object is masked from 'package:base':

    date

Loading required package: plotrix
Loading required package: pracma

Attaching package: 'MetFns'

The following object is masked from 'package:stats':

    filter

[1] 346.7399

MetFns documentation built on May 1, 2019, 6:28 p.m.