https://github.com/sharpcoder/altaz-js

A package for astronomy math in javascript
https://github.com/sharpcoder/altaz-js

astronomy math space

Last synced: 7 days ago
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A package for astronomy math in javascript

• Host: GitHub
• URL: https://github.com/sharpcoder/altaz-js
• Owner: SharpCoder
• Created: 2023-06-26T15:15:23.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-08-24T15:45:05.000Z (3 months ago)
• Last Synced: 2024-10-29T01:47:00.906Z (17 days ago)
• Topics: astronomy, math, space
• Language: TypeScript
• Homepage: https://www.npmjs.com/package/altaz
• Size: 69.3 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# AltAz

AltAz is a library for performing common astronomy calculations.

## Installation

Use any familiar package manager

```bash

pnpm install --save altaz

npm install --save altaz

yarn add altaz

```

## Usage

```typescript

// *************************************************

// Calculating days julian

// *************************************************

import { instantToDaysJulian } from "altaz";

const jday = instantToDaysJulian(now);

// *************************************************

// Calculating the position of a star at an instant

// *************************************************

import {

  Angle,

  GPSCoordinate,

  round,

  sphereToHorizontal,

  SphericalCoordinate,

  timeToAngle,

  timeToDec,

} from "altaz";

// Position of observer (Seattle)

const location = new GPSCoordinate(

    Angle.fromDegrees(47.608013),

    Angle.fromDegrees(-122.335167.),

);

// Position of the star

const skyTarget = {

  ra_h: 1.0,

  ra_m: 1.0,

  ra_s: 1.0,

  dec_deg: 1.0,

  dec_m: 1.0,

  dec_s: 1.0,

};

const starRightAscension = timeToAngle(

  parseFloat(skyTarget.ra_h),

  parseFloat(skyTarget.ra_m),

  parseFloat(skyTarget.ra_s)

);

const starDeclination = Angle.fromDegrees(

  parseFloat(skyTarget.dec_deg) +

    timeToDec(0, parseFloat(skyTarget.dec_m), parseFloat(skyTarget.dec_s))

);

const targetPosition = new SphericalCoordinate(

  1.0,

  starRightAscension,

  starDeclination

);

const targetAltAz = sphereToHorizontal(location, targetPosition, new Date());

// *************************************************

// Calculating the position of a planet at an instant

// *************************************************

import { Mercury, sphereToHorizontal } from "altaz";

// Position of observer (Seattle)

const location = new GPSCoordinate(

    Angle.fromDegrees(47.608013),

    Angle.fromDegrees(-122.335167.),

);

// Position of the planet

const targetPosition = Mercury.asSphere();

const targetAltAz = sphereToHorizontal(location, targetPosition, new Date());

```

## Installation

Build with the script

```bash

pnpm run build

npm run build

yarn run build

```

## Tests

I have tests somewhere. I'll migrate them eventually but I promise the math here is pretty well tested and used in a few simple production apps.

## Contributing

Please open an issue first to discuss what you would like to change and we'll go from there.

## License

[MIT](https://choosealicense.com/licenses/mit/)