SkyEye

Solar System Phenomena — 2020 Apparitions of the Inferior Planets from Latitude 10° North

What is an Apparition?

An apparition of a planet is the period during which it is visible, beginning and ending with solar conjunction. In the cases of the inferior planets Mercury and Venus, it is the time between inferior and superior conjunction (morning apparition) and the time between superior and inferior conjunction (evening apparition). Because inferior planets are always near the Sun, they only appear in the east before sunrise and the west after sunset.

Below are a series of diagrams showing the morning and evening apparitions of Mercury and Venus as observed from latitude 10° north. The planet is shown on the 1st, 6th, 11th, 16th, 21st and 26th days of each month with the current year's positions shown in bright white. The path may extend from the previous year or into the next.

Mercury

Mercury undergoes several morning and evening apparitions every year. This year finds Mercury both in the morning and evening skies four times.

11 November2019inferior conjunction: transit
28 Novembergreatest elongation west: 20.1°
10 January2020superior conjunction
10 Februarygreatest elongation east: 18.2°
26 Februaryinferior conjunction
24 Marchgreatest elongation west: 27.8°
04 Maysuperior conjunction: anti-transit
04 Junegreatest elongation east: 23.6°
01 Julyinferior conjunction
22 Julygreatest elongation west: 20.1°
17 Augustsuperior conjunction
01 Octobergreatest elongation east: 25.8°
25 Octoberinferior conjunction
10 Novembergreatest elongation west: 19.1°
20 Decembersuperior conjunction
24 January2021greatest elongation east: 18.6°
08 Februaryinferior conjunction

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The first of January finds Mercury finishing the last morning apparition of 2019 (blue track). However, it is less than 5° in altitude and soon vanishes below the horizon. The second morning apparition (pink track) occurs between late February and early May and is the best dawn appearance of the year, with Mercury rising to over 21° in altitude. It is fifth-magnitude at the beginning of the apparition but brightens to magnitude −2.2 before it disappears. The following morning apparition in July and August (green track) is nearly as favourable, with Mercury climbing nearly 20° in the east. As is always the case with a morning apparition, Mercury begins as a faint object low in the east before brightening by several magnitudes over the course of its dawn appearance. Mercury arrives in the east one more time (orange track) in late October, rising over 17° before plunging back toward the horizon before the end of the year.

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Mercury makes its first evening appearance in mid-January (blue track), reaching a maximum altitude of 17° in what is the poorest of the three complete western apparitions this year. This appearance is followed the most favourable apparition in May and June (pink track) when Mercury vaults to a maxiumum altitude of nearly 23° in early June. Evening apparitions are characterised by bright magnitudes at the beginning of the show and very faint magnitudes by the time the planet dips back below the horizon. In this case, Mercury first appears at magnitude −2 and ends at +6. Mercury next appears in the evening skies in mid-August (green track), reaching a maximum altitude of 19° in late September before disappearing in the west in late October. The last apparition in the west occurs at the very end of December (orange track) but will be difficult to see as Mercury is barely 6° above the horizon.

Venus

Venus spends the first part of the year as the evening star, then switches to dawn skies in early June.

17 August2019superior conjunction
24 March2020greatest elongation east: 46.1°
03 Juneinferior conjunction
13 Augustgreatest elongation west: 45.8°
26 March2021superior conjunction

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The morning star first appears in early June, rapidly gaining altitude in the east-northeast. This is an excellent apparition, with Venus reaching a maximum altitude of 45° around 10 August. It spends the rest of the year leisurely moving southeast and slowly approaching the horizon. By the end of the year, the planet is still nearly 19° high. Venus reaches maximum brightness (magnitude −4.5) in early July and ends the year at a still bright −3.9.

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Venus continues last year's evening apparition during the first five months of 2020. Already 33° above the southwestern horizon at the beginning of January, Venus slowly climbs another ten degrees until mid-March when it heads back toward the horizon. Its altitude sharply declines from April and the evening star vanishes at the beginning of June. Venus begins the year at magnitude −4.0, brightening to −4.5 in late April and ending its evening appearance at −3.7.

Sources

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.