Almanac · Planets
Saturn at opposition, 18 Oct 2027
Saturn is at opposition on Mon 18 Oct 2027 at 00:27 UTC: opposite the Sun in the sky, so it rises at sunset, is up all night and is near its brightest for the year.
- Opposition Up from sunset to sunrise
- Brightness +0.1 Magnitude: lower is brighter; the brightest stars are near 0
- Distance 8.326 AU 1245.6 million km; its disc 20.0″ across
Latitude by latitude
At each latitude, the moment within 12 hours of the event, with the Sun at least 6° below the horizon, that Saturn stands highest, and how high. Times are local solar time: your clock may differ by up to an hour or two, by your time zone.
| Latitude | Best moment | The Sun then | What you see |
|---|---|---|---|
| 60°N | 23:47 | 39° down | 37° up in the S at 23:47 |
| 45°N | 23:47 | 54° down | 52° up in the S at 23:47 |
| 30°N | 23:47 | 69° down | 67° up in the S at 23:47 |
| 15°N | 23:47 | 84° down | 82° up in the S at 23:47 |
| 0° | 23:47 | 81° down | 83° up in the N at 23:47 |
| 15°S | 23:47 | 66° down | 68° up in the N at 23:47 |
| 30°S | 23:47 | 51° down | 53° up in the N at 23:47 |
| 45°S | 23:57 | 36° down | 38° up in the N at 23:57 |
How we worked it out: the planets are placed by VSOP87, the planetary theory the map draws, within about an arcsecond of JPL’s ephemeris, and the Sun by Meeus’s solar theory. Opposition is the instant Saturn’s longitude along the ecliptic is the Sun’s plus 180°, found to the minute; its nearest approach to the Earth is the least of its distance within a month either side. Each latitude is walked every 10 minutes over the 12 hours either side, at Greenwich’s longitude. The tests hold the dates to the U.S. Naval Observatory’s and the published calendars’, within a day, and the angles within 0.3°.
- P. Bretagnon and G. Francou, VSOP87, the planetary theory the map draws, held to JPL’s DE441 within about an arcsecond over 1900–2100
- U.S. Naval Observatory and Sea and Sky’s Astronomy Calendar of Celestial Events: the dates and angles the tests hold these to
- A. Mallama and J. Hilton (2018) and the Astronomical Almanac’s phase-angle series: the planets’ magnitudes
- J. Meeus, Astronomical Algorithms, ch. 25: the Sun, for the twilight each latitude is judged in