Carrington rotations
Convert a date to its Carrington rotation number and back, and browse rotation start and end times.
CR 5724
| Start | March 27, 2281 at 07:17 AM UTC |
|---|---|
| End | April 23, 2281 at 02:02 PM UTC |
| Length (days) | 27.28 |
Neighbouring rotations
| CR | Start | End | Length (days) |
|---|---|---|---|
| 5719 | November 10, 2280 at 04:01 PM UTC | December 7, 2280 at 11:29 PM UTC | 27.31 |
| 5720 | December 7, 2280 at 11:29 PM UTC | January 4, 2281 at 07:19 AM UTC | 27.33 |
| 5721 | January 4, 2281 at 07:19 AM UTC | January 31, 2281 at 03:27 PM UTC | 27.34 |
| 5722 | January 31, 2281 at 03:27 PM UTC | February 27, 2281 at 11:36 PM UTC | 27.34 |
| 5723 | February 27, 2281 at 11:36 PM UTC | March 27, 2281 at 07:17 AM UTC | 27.32 |
| 5724 | March 27, 2281 at 07:17 AM UTC | April 23, 2281 at 02:02 PM UTC | 27.28 |
| 5725 | April 23, 2281 at 02:02 PM UTC | May 20, 2281 at 07:45 PM UTC | 27.24 |
| 5726 | May 20, 2281 at 07:45 PM UTC | June 17, 2281 at 12:41 AM UTC | 27.21 |
| 5727 | June 17, 2281 at 12:41 AM UTC | July 14, 2281 at 05:25 AM UTC | 27.20 |
| 5728 | July 14, 2281 at 05:25 AM UTC | August 10, 2281 at 10:31 AM UTC | 27.21 |
| 5729 | August 10, 2281 at 10:31 AM UTC | September 6, 2281 at 04:17 PM UTC | 27.24 |
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.