Solar System Phenomena — Saturn in 2018

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The upper chart shows the path of Saturn across the background stars over the course of the year. Stars to magnitude +8.5 are shown. The white circles represent the planet on the first day of the month and are scaled according to apparent magnitude. The faint paths before the first circle and after the last circle represent the planet's positions in December of last year and January of next. In general, the planet moves from right to left except when it's in retrograde and proceding in the opposite direction.

The lower chart shows how the appearance of Saturn changes over the year. Below each image is listed the date, the apparent magnitude, the apparent diameter of the disk (in arc-seconds), the geocentric distance (in au) and the opening angle of the rings. Note that the tilt of Saturn's rings varies subtly throughout the year.

The ringed planet spends the entirety of 2018 in the crowded star fields of the constellation Sagittarius. Its southerly declination makes it a more difficult observing target for observers in temperate northern latitudes than for those in equatorial and southern regions on Earth. At conjunction late last year, Saturn is lost in the glare of the Sun at the beginning of 2018 but eventually distances itself from our star and can be seen from February onwards. It reaches zero magnitude at opposition in June. East quadrature in September rewards astrophotographers since the rings are also at their most open as seen from our planet. An evening sky object for the second half of the year, Saturn is lost to view by the end of 2018 as it approaches its next conjunction in early 2019.

11 February2.0° south of the Moon
11 March2.0° south of the Moon
29 Marchwest quadrature
02 April1.3° north of Mars
07 April1.7° south of the Moon
17 Aprilaphelion
18 Aprilstationary point: direct → retrograde
19 Aprilmaximum declination north
04 May1.7° south of the Moon
01 June1.7° south of the Moon
27 Juneopposition: magnitude +0.1, apparent diameter 18.4 arc-seconds
25 July2.0° south of the Moon
21 August2.0° south of the Moon
06 Septemberstationary point: retrograde → direct
17 September2.0° south of the Moon
19 Septembermaximum ring opening: 26.6°
25 Septembereast quadrature
15 October1.8° south of the Moon
21 Octobermaximum declination south
11 November1.5° south of the Moon
09 Decemberlunar occultation: 1.1° south of the Moon
31 Decemberminimum ring opening: 25.5°
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The dates, times and circumstances of all planetary and lunar phenomena were calculated from the JPL DE406 solar system ephemeris using the same rigorous methods that are employed in the compilation of publications such as The Astronomical Almanac.