SkyEye

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 in the morning skies four times and the evening skies thrice.

Mercury is already heading toward the horizon at the beginning of the year, finishing the excellent final morning apparition of 2018 (blue track), but better things are to come in March through May (pink track). In early April, the tiny planet reaches a year's best altitude of nearly 21°. Although the apparition begins with the planet only sixth magnitude, it brightens throughout its time above the horizon, moving into bright negative magnitudes in late April. The third apparition (green track) is not quite as favourable although Mercury is fairly bright in August. The final apparition of the year (orange track) follows a similar path to the first one, with Mercury rising 19° into the sky and attaining a magnitude of −1.2 by the end of December.

The first evening apparition (blue track) begins in February, with Mercury reaching a maximum altitude of nearly 17° and shining brightly until early March. The best apparition is undoubtedly the next (pink track), when the planet reappears in late May and races to a height of 24° above the northwestern horizon. Beginning its run at magnitude −2.2, it dims to first magnitude by the time it reaches its highest point and continues to fade as it heads back toward the Sun. The final apparition (green track) begins in early September and ends two months later. As is always the case with evening apparitions of Mercury, the planet starts out bright (magnitude −1.9 in this case) and slowly fades until it is lost in the Sun's glare. This apparition finds Mercury as high as 18° above the horizon.

Venus

Venus spends the first part of the year as the morning star then switches to western skies in August.

The morning apparition of Venus is a continuation of the 2018 end-of-year appearance of the planet. It is never higher or brighter than on the first day of January but it nevertheless gives a fine performance as the morning star.

Following the August superior conjunction, Venus rapidly returns to view, this time in the west after sunset. This is a good apparition, with Venus reaching magnitude −4.0 by year's end and eventually attaining an altitude of over 42° in 2020.

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.