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https://github.com/mendahu/mars-date-utils
JavaScript Library for working with time on Mars
https://github.com/mendahu/mars-date-utils
Last synced: 2 months ago
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JavaScript Library for working with time on Mars
- Host: GitHub
- URL: https://github.com/mendahu/mars-date-utils
- Owner: mendahu
- License: agpl-3.0
- Created: 2021-04-11T13:38:03.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-10-17T15:17:08.000Z (about 3 years ago)
- Last Synced: 2024-10-28T13:35:00.219Z (2 months ago)
- Language: TypeScript
- Size: 194 KB
- Stars: 16
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Mars Date Utilities
Zero dependency JavaScript library for working with time on Mars.
## Getting Started
Create a new instance of a MarsDate by passing it an Earth Date.
```javascript
import { MarsDate } from "mars-date-utils";
const spiritRoverLanding = new Date(1073190900000);
// 2004-01-04T04:35:00.000Z
const marsDate = new MarsDate(spiritRoverLanding);
```
## Basic Time Methods
These methods return the DateTime on Mars for your given Earth DateTime. `mars-date-utils` can return the Mars Year, Solar Longitude (used by scientists to determine seasonality) and Mean Solar Time at Mars Prime Meridien (longitude 0).
```javascript
marsDate.getCalendarYear(); // 26
// Returns the Mars Year, with Year 1 beginning April 11 1955 at 00:00:00 UTC
marsDate.getLs(); // 327.66627413425294
// Returns the Ls (solar longitude)
marsDate.getMST(); // "03:34:38"
// Returns the Mean Solar Time (equivalent to Earth's UTC)
marsDate.getEarthDate(); // 2004-01-04T04:35:00.000Z
// Return back Earth Date Object
```
## Longitude-Specific Time Methods
By passing these methods a longitude (degrees west from Prime Meridien), you can retrieve the local mean solar time or local true solar time from a specific location of your Mars DateTime.
```javascript
const landingSiteLongitude = 184.527364; // Degrees West of Mars Prime Meridien
marsDate.getLMST(landingSiteLongitude); // "15:16:31"
// Returns Local Mean Solar Time at a specific longitude
marsDate.getLTST(landingSiteLongitude); // "14:25:24"
// Returns Local True Solar Time at a specific longitude
```
## Age Methods
These methods calculate age from your Mars DateTime until now.
```javascript
marsDate.getAgeInYears(); // 9.185908911135375
//Returns age in Mars Years
marsDate.getAgeInSols(); // 6141.690430655763
//Returns age in Mars Sols
marsDate.getAgeInSeconds(); // 545230062.457
//Returns age in Seconds
```
## Special Age Methods
Other useful age methods.
```javascript
marsDate.getSolOfMission(landingSiteLongitude); // 6142
// Returns the day number since date at location,
// assuming date starts on Sol 0 and ticks over at local midnight.
// Useful for calculating what sol a space mission is on.
const n = 1;
marsDate.getAnniversary(n); // 2005-11-21T04:05:48.240Z
// Returns the nth Mars anniversary of the Mars Date.
// Example of n = 1 returns 1 Mars year since Spirit Landing.
// Returns regular Earth Date object.
marsDate.getNextAnniversary(n); // 2022-10-25T23:43:02.406Z
// Considering the original Mars Date, returns the Mars next anniversary of that date.
// n defaults to 1 but can be incremented to return n anniversaries from now
// Returns a regular Date object from which you can get the date on Earth
// Useful for finding your next Mars Birthday. 🎂
```
## Solar Position Methods
Methods to work with the position of the sun.
```javascript
const options = {
unit: "au", // default
};
marsDate.getHeliocentricDistance(options); // 1.4784561362455526
// Returns the distance between the centre of Mars and the centre
// of the Sun on the given Mars Date. Defaults to "AU" as a unit
// but can optionally be passed "km" for kilometres
```
```javascript
const lat = -14.5684;
const lon = 184.527364; // Degrees West of Mars Prime Meridien
marsDate.getSolarElevation(lat, lon); // 54.726577500467855
// Return the elevation of the sun, in degrees, from the horizon (0
// is at the horizon, 90 is straight up). A negative number indicates
// the sun is below the horizon (ie. it is night time).
marsDate.getSolarAzimuth(lat, lon); // 267.47987404238927
// Return the solar azimuth (compass direction of the sun) in degrees
// clockwise from North. 0 degrees is North, 90 is East, 180 is South and 270 is West
```
## Earth and Mars Relationship Methods
Methods exploring time and distance between Earth and Mars
```javascript
const options = {
unit: "au", // default
};
marsDate.getDistanceBetweenEarthAndMars(options); // 1.1387184676741797
// Returns the distance between the centre of Mars and the centre
// of the Earth on the given Mars Date. Defaults to "AU" as a unit
// but can optionally be passed "km" for kilometres
```
```javascript
marsDate.getLightDelay(); // 568.2259628119933
// Returns the time (in seconds) it would take light to travel between the
// centre of the Earth and the centre of Mars. Useful to determine one way
// radio signal delay when communicating with Spacecraft.
```