https://github.com/rstub/swephr

High Precision Ephemeris
https://github.com/rstub/swephr

ephemeris r

Last synced: 19 days ago
JSON representation

High Precision Ephemeris

• Host: GitHub
• URL: https://github.com/rstub/swephr
• Owner: rstub
• Created: 2018-08-06T21:57:47.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2024-06-30T11:14:27.000Z (5 months ago)
• Last Synced: 2024-10-24T15:55:23.813Z (26 days ago)
• Topics: ephemeris, r
• Language: C
• Homepage: https://rstub.github.io/swephR/
• Size: 13.1 MB
• Stars: 10
• Watchers: 5
• Forks: 1
• Open Issues: 3
• Metadata Files:
  • Readme: README.Rmd
  • Changelog: NEWS.md

Awesome Lists containing this project

README

        
---

output: github_document

---

```{r setup, include = FALSE}

knitr::opts_chunk$set(

  collapse = TRUE,

  comment = "#>",

  fig.path = "man/figures/README-",

  out.width = "100%"

)

```

[![R build status](https://github.com/rstub/swephR/workflows/R-CMD-check/badge.svg)](https://github.com/rstub/swephR/actions)

[![Coverage status](https://codecov.io/gh/rstub/swephR/branch/master/graph/badge.svg)](https://app.codecov.io/github/rstub/swephR?branch=master)

[![CRAN status](https://www.r-pkg.org/badges/version/swephR)](https://cran.r-project.org/package=swephR)

[![Downloads](https://cranlogs.r-pkg.org/badges/swephR?color=brightgreen)](https://www.r-pkg.org/pkg/swephR)

[![Dependencies](https://tinyverse.netlify.com/badge/swephR)](https://cran.r-project.org/package=swephR)

# swephR

The goal of swephR is to provide an R interface to the [Swiss

Ephemeris](https://www.astro.com/swisseph/). The Swiss Ephemeris is a

high precision ephemeris based upon the DE431 ephemeris from NASA's

JPL. It covers the time range 13201 BCE to 17191 CE.

## Installation

You can install the released version of swephR from [CRAN](https://CRAN.R-project.org) with:

``` r

install.packages("swephR")

```

Intermediate releases can also be obtained from https://rstub.r-universe.dev/:

``` r

install.packages('swephR', repos = c('https://rstub.r-universe.dev', 'https://cloud.r-project.org'))

```

This package uses the semi-analytic theory by Steve Moshier.  For

faster and more accurate calculations, the compressed Swiss Ephemeris

data is available in the `swephRdata` package. To access this data

package, run

``` r

install.packages("swephRdata", repos = "https://rstub.r-universe.dev", type = "source")

```

The size of the `swephRdata` package is approximately 115 MB. The user

can also use the original JPL DE431 data.

## Example

To compute the position of celestial body or star with SE (Swiss

Ephemeris), you do the following steps:

```{r}

library(swephR)

swe_version()

```

For a specific date, compute the Julian day number (in below example:

J2000.0, 1 January 2000 at 12:00 UT):

```{r}

year <- 2000

month <- 1

day <- 1

hour <- 12

jdut <- swe_julday(year, month, day, hour, SE$GREG_CAL)

jdut

```

Compute (using Moshier ephemeris) the positions (longitude, latitude,

distance, longitude speed and latitude speed) of a planet or other

celestial bodies (in below example: the Sun):

```{r}

ipl <- SE$SUN

iflag <- SE$FLG_MOSEPH + SE$FLG_SPEED

result <- swe_calc_ut(jdut, ipl, iflag)

result

```

or a fixed star (in below example: Sirius):

```{r}

starname = "sirius"

result <- swe_fixstar2_ut(starname, jdut, iflag)

result

```

The current R interface is modeled after the C interface. It is

therefore often helpful to consult the [general

documentation](https://www.astro.com/swisseph/swisseph.htm) and

[programmer's

documentation](https://www.astro.com/swisseph/swephprg.htm) for the

Swiss Ephemeris.

## Feedback

All feedback (bug reports, security issues, feature requests, ...) should be provided as

[issues](https://github.com/rstub/swephR/issues).