Carrington rotations
Convert a date to its Carrington rotation number and back, and browse rotation start and end times.
CR 8985
| Start | October 3, 2524 at 01:12 PM UTC |
|---|---|
| End | October 30, 2524 at 08:04 PM UTC |
| Length (days) | 27.29 |
Neighbouring rotations
| CR | Start | End | Length (days) |
|---|---|---|---|
| 8980 | May 20, 2524 at 10:27 AM UTC | June 16, 2524 at 03:29 PM UTC | 27.21 |
| 8981 | June 16, 2524 at 03:29 PM UTC | July 13, 2524 at 08:12 PM UTC | 27.20 |
| 8982 | July 13, 2524 at 08:12 PM UTC | August 10, 2524 at 01:13 AM UTC | 27.21 |
| 8983 | August 10, 2524 at 01:13 AM UTC | September 6, 2524 at 06:52 AM UTC | 27.24 |
| 8984 | September 6, 2524 at 06:52 AM UTC | October 3, 2524 at 01:12 PM UTC | 27.26 |
| 8985 | October 3, 2524 at 01:12 PM UTC | October 30, 2524 at 08:04 PM UTC | 27.29 |
| 8986 | October 30, 2524 at 08:04 PM UTC | November 27, 2524 at 03:19 AM UTC | 27.30 |
| 8987 | November 27, 2524 at 03:19 AM UTC | December 24, 2524 at 10:57 AM UTC | 27.32 |
| 8988 | December 24, 2524 at 10:57 AM UTC | January 20, 2525 at 06:56 PM UTC | 27.33 |
| 8989 | January 20, 2525 at 06:56 PM UTC | February 17, 2525 at 03:08 AM UTC | 27.34 |
| 8990 | February 17, 2525 at 03:08 AM UTC | March 16, 2525 at 11:08 AM UTC | 27.33 |
About this tool
A Carrington rotation is the time the Sun takes to turn once on its axis as seen from the Earth: 27.2753 days on average. The count was defined by the English astronomer Richard Carrington, who studied sunspots in the 1850s; rotation 1 began on 9 November 1853, and the numbering has run without interruption since.
Explorer computes the start of each rotation with the formula given by Jean Meeus in Astronomical Algorithms (chapter 29), implemented in its own astronomy library and checked against published dates. A rotation begins when the Carrington longitude L₀ of the central meridian passes through 0°; because the Earth moves along its orbit, the synodic period varies slightly around the mean, hence lengths of 27.2 to 27.3 days.
Observers use the rotation number as a calendar for the Sun: an active region that crosses the disc reappears about one rotation later, and the community activity heatmap shows one row per rotation so that returning regions line up. Enter a date to find its rotation, or a number to get the UTC start and end dates and the neighbouring rotations.