Perigee
The point of the Moon’s orbit at which the Moon stands closest to the Earth. In the biodynamic planting calendar the twelve hours before and after count as unfavourable for sowing.
What is perigee?
The Moon’s orbit is an ellipse. Its point closest to the Earth is called perigee, its furthest point apogee. At perigee the centres of Earth and Moon are about 356,400 to 370,400 km apart. From one perigee to the next takes 27.55 days on average, the anomalistic month.
How close the Moon comes varies from month to month, because the Sun pulls on the Moon’s orbit. It comes closest when perigee falls on New Moon or Full Moon. In 2027 the closest perigee is on 21 January at 357,283 km, the most distant on 14 April at 370,007 km.
The line between perigee and apogee is called the line of apsides. It turns forwards and takes just under nine years to go once round.
Perigee in the biodynamic calendar
Biodynamic practice avoids perigee for sowing. Dyyna blocks twelve hours before and twelve hours after perigee, whatever the day type. The moment of perigee is the moment at which the Moon stands closest to the Earth.
If a Full Moon falls close to perigee, it appears larger and brighter than usual. This is called a supermoon. Perigee has nothing to do with the ascending and descending Moon: the Moon can be ascending or descending at perigee.
Perigee 2027
| Date | Time | Distance | Unfavourable |
|---|---|---|---|
| 21 Jan | 22:47 | 357,283 km | 10:47 – 10:47 (22 Jan) |
| 19 Feb | 8:29 | 361,015 km | 20:29 (18 Feb) – 20:29 |
| 19 Mar | 5:29 | 366,441 km | 17:29 (18 Mar) – 17:29 |
| 14 Apr | 2:28 | 370,007 km | 14:28 (13 Apr) – 14:28 |
| 9 May | 22:07 | 366,629 km | 10:07 – 10:07 (10 May) |
| 6 Jun | 16:54 | 361,698 km | 4:54 – 4:54 (7 Jun) |
| 4 Jul | 22:57 | 358,283 km | 10:57 – 10:57 (5 Jul) |
| 2 Aug | 8:24 | 357,364 km | 20:24 (1 Aug) – 20:24 |
| 30 Aug | 17:40 | 359,206 km | 5:40 – 5:40 (31 Aug) |
| 27 Sep | 22:11 | 363,451 km | 10:11 – 10:11 (28 Sep) |
| 25 Oct | 7:35 | 368,653 km | 19:35 (24 Oct) – 19:35 |
| 19 Nov | 1:12 | 369,366 km | 13:12 (18 Nov) – 13:12 |
| 16 Dec | 3:24 | 364,027 km | 15:24 (15 Dec) – 15:24 |
Times for Central Europe (CET, CEST in summer). The “Unfavourable” column shows the window in which Dyyna blocks sowing.
Sources
- Apsis, Wikipedia
- Orbit of the Moon, Wikipedia
- Orbital data: Jean Meeus, Astronomical Algorithms, 2nd edition, Willmann-Bell 1998
Frequently asked questions about perigee
What does perigee mean in a moon calendar?
The moment at which the Moon stands closest to the Earth. The biodynamic calendar counts the twelve hours before and after as unfavourable for sowing.
How often is the Moon at perigee?
Once in every anomalistic month, so about every 27 ½ days. There are 13 perigees in 2027.
How close does the Moon come to the Earth?
At perigee between about 356,400 and 370,400 km, measured from centre to centre. In 2027 it comes within 357,283 km on 21 January.
Is perigee the same as a supermoon?
Perigee is a point of the Moon’s orbit and comes round every month. A supermoon is a Full Moon that falls close to this point.