[**pray-calc v2.1.1**](../README.md)

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[pray-calc](../README.md) / toJulianDate

# Function: toJulianDate()

> **toJulianDate**(`date`): `number`

Defined in: [getSolarEphemeris.ts:22](https://github.com/acamarata/pray-calc/blob/4227afc2c3993234794b3a1a561c080edc6d4d4e/src/getSolarEphemeris.ts#L22)

Convert a JavaScript Date to a Julian Date number.

## Parameters

### date

`Date`

Any JavaScript Date object (uses UTC internally)

## Returns

`number`

Julian Date: days since noon January 1, 4713 BC UTC

## Example

```ts
const jd = toJulianDate(new Date('2024-06-21'));
// jd ≈ 2460482.5
```