Solar System Phenomena — Venus in 2018

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The upper chart shows the path of Venus across the background stars over the course of the year. Stars to magnitude +4.5 are shown with some fainter objects included to complete constellation patterns. 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. As an inferior planet, Venus never strays far from the Sun so it always begins and ends the year near the constellation of Sagittarius, located about one quarter of the way in from the left side of the chart.

The lower charts show how the appearance of Venus 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), the elongation from the Sun (in degrees) and the percentage of the disk which is illuminated. Like the Moon, Venus exhibits a complete range of phases, from new to crescent to gibbous to full and back again. Unlike the Moon, however, Venus takes over a year to complete this phase cycle. Note how Venus is at its brightest during its crescent phase, when it is relatively close to the Earth.

Venus remains too close to the Sun to observe for the first month or so of the year, finally appearing low in the west as the evening star by late February. This apparition favours observers in equatorial and southern regions. It passes close to Regulus in July and Spica two months later. Venus eventually loses altitude and is gone from view in October (early in the month for the northern hemisphere and very late in the month for the southern hemisphere) when it reaches inferior conjunction on 26 October. It quickly reappears in November as the morning star where it remains for the rest of the year.

01 Januaryelongation 2.0°, illuminated fraction 99.9%, magnitude −3.9, disk diameter 9.8 arc-seconds
maximum declination south
09 Januarysuperior conjunction
17 JanuarySagittariusCapricornus
23 Januaryaphelion
01 Februaryelongation 5.6°, illuminated fraction 99.6%, magnitude −3.9, disk diameter 9.9 arc-seconds
08 FebruaryCapricornusAquarius
16 Februaryoccultation by the Moon — not visible
01 Marchelongation 12.3°, illuminated fraction 97.9%, magnitude −3.9, disk diameter 10.1 arc-seconds
02 MarchAquariusPisces
05 March1.4° north of Mercury
12 MarchPiscesCetus
14 MarchCetusPisces
30 MarchPiscesAries
01 Aprilelongation 19.8°, illuminated fraction 94.2%, magnitude −3.9, disk diameter 10.7 arc-seconds
12 Aprilascending node
19 AprilAriesTaurus
01 Mayelongation 27.1°, illuminated fraction 88.5%, magnitude −3.9, disk diameter 11.6 arc-seconds
15 Mayperihelion
19 MayTaurusGemini
22 Maymaximum declination north
01 Juneelongation 34.4°, illuminated fraction 80.2%, magnitude −4.0, disk diameter 13.2 arc-seconds
12 JuneGeminiCancer
16 June2.0° north of the Moon
20 June0.7° north of the open star cluster M44 (known as Praesepe or the Beehive Cluster)
29 JuneCancerLeo
01 Julyelongation 40.6°, illuminated fraction 70.0%, magnitude −4.1, disk diameter 15.9 arc-seconds
09 July1.1° north of Regulus
16 July1.6° south of the Moon
01 Augustelongation 45.1°, illuminated fraction 57.0%, magnitude −4.2, disk diameter 20.6 arc-seconds
descending node
17 Augustgreatest elongation east: 45.9°
01 Septemberelongation 45.1°, illuminated fraction 40.3%, magnitude −4.4, disk diameter 29.4 arc-seconds
02 September1.4° south of Spica
05 Septemberaphelion
25 Septembermaximum magnitude −4.6
01 Octoberelongation 33.3°, illuminated fraction 16.7%, magnitude −4.5, disk diameter 46.6 arc-seconds
05 Octoberstationary point: direct → retrograde
08 OctoberLibraVirgo
26 Octoberinferior conjunction
01 Novemberelongation 10.0°, illuminated fraction 1.1%, magnitude −4.1, disk diameter 61.1 arc-seconds
14 Novemberstationary point: retrograde → direct
22 Novemberascending node
30 Novembermaximum magnitude −4.7
01 Decemberelongation 39.6°, illuminated fraction 25.7%, magnitude −4.7, disk diameter 41.0 arc-seconds
13 DecemberVirgoLibra
26 Decemberperihelion


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.