v2.0.0

SunCalc 2.0 is a precision-focused rewrite that matches the accuracy and conventions of timeanddate.com and the U.S. Naval Observatory. It now ships as a modern ES module with TypeScript declarations, plus a bundled CommonJS/UMD build for legacy require() and <script> use.

Dramatically improved accuracy ⚡

Every function was rebuilt on higher-order astronomical models (Jean Meeus' Astronomical Algorithms) and validated against JPL Horizons and the USNO. Typical errors versus v1:

	v1	v2
Sun position	~0.43°	~0.08°	~5× better
Sun rise/set times	~75 s	~15 s	~5× better
Moon position	~1.2°	~0.09°	~14× better
Moon rise/set times	~5 min	~15 s	~20× better
Moon distance	~3500 km	~20 km	~150× better

Sun and moon times are now accurate to ~15 seconds — at the floor of what the USNO's whole-minute reference data can even measure.

Breaking changes ⚠️

• ESM-first. The source is now a native ES module — import * as SunCalc from 'suncalc'. A bundled UMD build still supports require('suncalc') and direct <script> tags (global SunCalc, also on unpkg / jsDelivr).
• Angles in degrees. Every angle in and out — altitude, azimuth, illumination angle, parallactic angle — is in degrees, not radians.
• North-based azimuth. Azimuth is measured clockwise from north: 0 = N, 90 = E, 180 = S, 270 = W (v1 measured from south).
• Apparent altitude. getPosition / getMoonPosition now return the apparent (atmospheric-refraction-corrected) altitude, so positions near the horizon match what you actually observe.
• Dates are UTC instants. Inputs and outputs are absolute moments in time; no local-timezone conversion is applied. getTimes resolves the input date's solar day regardless of the time-of-day you pass (in v1 you had to pass noon to avoid off-by-one-day surprises).
• getMoonTimes scans the UTC day of the given date; the inUTC argument has been removed. For a local-civil-day window, pass a date set to local midnight.
• Missing events are null. When an event doesn't occur (e.g. the sun never rises at high latitudes), its time is null rather than an Invalid Date, and getTimes sets alwaysUp / alwaysDown accordingly.

Other changes

• Added a waxing flag to getMoonIllumination.
• Bundled hand-written TypeScript declarations (index.d.ts).