Solar System Phenomena — Mars in 2019

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The upper chart shows the path of Mars 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.

The lower chart shows how the appearance of Mars 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 percentage of the disk which is illuminated. Note that Mars appears distinctly gibbous near the times of quadrature.

An excellent opposition year is inevitably followed by a poor conjunction year and that is the case in 2019. Mars underwent a very favourable opposition in 2018 so it remains rather distant and dim for the entire year this year. It makes a direct path across the background stars, beginning in Pisces and ending in Libra. Near zero magnitude in January, it eventually dims to second magnitude before recovering slightly by the end of the year. An evening sky object for much of the year, it disappears from view around August as it closes in on the Sun and undergoes conjunction in September. Afterwards the red planet reappears in the morning sky where it remains for the rest of the year.

15 Januaryascending node
13 FebruaryPiscesAries
1.0° north of Uranus
23 MarchAriesTaurus
23 Marchequinox: spring in the northern hemisphere and autumn in the southern hemisphere
16 MayTaurusGemini
maximum declination north
05 June1.6° north of the Moon
18 Juneplanetary conjunction: 0.2° south of Mercury
28 JuneGeminiCancer
04 Julylunar occulation: 0.1° north of the Moon
08 Julyplanetary conjunction: 4.1° north of Mercury
13 July0.4° south of the open star cluster M44 (known as Praesepe or the Beehive Cluster)
30 JulyCancerLeo
01 August1.7° south of the Moon
24 Augustplanetary conjunction: 0.3° south of Venus
26 Augustaphelion
02 Septemberconjunction
03 Septemberplanetary conjunction: 0.6° south of Mercury
24 SeptemberLeoVirgo
08 Octobersolstice: summer in the northern hemisphere and winter in the southern hemisphere
01 DecemberVirgoLibra
31 Decembermaximum declination south


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.