Solar ephemeris
P, B₀, L₀, right ascension, declination and Julian day for any UTC instant.
October 16, 2026 at 11:54 PM UTC
| Carrington rotation | CR 2316 |
|---|---|
| Julian day | 2461330.49600 |
| P | 26.09° |
| B₀ | 5.75° |
| L₀ | 83.38° |
| Right ascension | 13h 27m |
| Declination | -9.18° |
About this tool
The physical ephemeris of the Sun describes how the solar disc is oriented for an observer on Earth at a given instant. P is the position angle of the Sun’s rotation axis, measured from celestial north towards the east, and swings between −26.3° and +26.3° over the year. B₀ is the heliographic latitude of the centre of the disc, within ±7.25°: it tells whether we see slightly more of the northern or of the southern hemisphere. L₀ is the Carrington longitude of the central meridian, decreasing by about 13.2° per day.
These three angles, together with the Sun’s right ascension and declination, come from Explorer’s own implementation of the algorithms of Jean Meeus (Astronomical Algorithms, chapters 25 and 29), validated against the worked examples of the book to a few hundredths of a degree — ample for orienting a drawing or a photograph. Times are in UTC; the Julian day and the Carrington rotation of the instant are given for cross-reference.
In practice you need P to mark celestial north on a drawing and rotate it to the solar axis, B₀ to choose the right Stonyhurst grid, and L₀ to convert a spot’s position into Carrington coordinates that stay fixed as the Sun rotates. Pick any date and time, or use the values of the current instant.