Mars at perigee

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

2285 apparition of Mars

12 May 2285 – Mars enters retrograde motion
15 Jun 2285 – Mars at opposition
23 Jun 2285 – Mars at perigee
21 Jul 2285 – Mars ends retrograde motion

Mars's orbit around the Sun will carry it to its closest point to the Earth – its perigee – passing within 0.46 AU of us.

The days around perigee represent the best time to observe Mars, since both its size and brightness in the night sky increase when it is close to us.

This effect is especially dramatic for Mars since it neighbours the Earth in the Solar System, orbiting a little further out from the Sun than us, at an average distance of 1.52 AU. As a result, it has the greatest variation of all the planets in its distance from the Earth, depending on whether the two planets are on opposite sides of the Sun, or passing next to one another in their respective orbits.

Mars reaches perigee at around the time when it passes the Earth in its orbit. At this time, the Sun, Earth and Mars lie in a straight line, with the Earth in the middle.

Consequently, Mars appears almost exactly opposite the Sun in the sky – a configuration called opposition, when Mars reaches its highest point in the sky at midnight and is visible for much of the night.

Every perigee of Mars is associated with a near-simultaneous opposition, but the two events typically occur a few days apart owing to the significant ellipticity of Mars's orbit.

On this occasion, Mars will attain a maximum angular diameter of 20.5 arcsec at closest approach, and a maximum brightness of magnitude -2.3 .

Observing Mars

Even at its closest approach to the Earth, it is never possible to distinguish Mars as more than a star-like point of light with the naked eye, though a simple pair of binoculars is sufficient to reveal it as a disk of light.

From South El Monte , it will be visible in the evening sky, becoming accessible around 20:09 (PST), 10° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 23:48, 29° above your southern horizon. It will continue to be observable until around 03:41, when it sinks below 7° above your south-western horizon.

A chart of the path of Mars across the sky in 2285 can be found here, and a chart of its rising and setting times here.

The table below lists Mars' angular size and brightness at two-week intervals throughout its apparition:

Date Right ascension Declination Angular size Magnitude
06 Apr 228517h18m10s22°51'S10.6”-0.2
20 Apr 228517h35m40s23°31'S12.3”-0.6
04 May 228517h46m20s24°10'S14.3”-1.1
18 May 228517h47m20s24°54'S16.6”-1.5
01 Jun 228517h37m40s25°41'S18.8”-2.0
15 Jun 228517h19m20s26°18'S20.2”-2.3
29 Jun 228516h59m30s26°33'S20.4”-2.2
13 Jul 228516h46m30s26°31'S19.3”-1.9
27 Jul 228516h45m10s26°30'S17.6”-1.6
10 Aug 228516h55m30s26°37'S15.8”-1.3
24 Aug 228517h15m40s26°47'S14.1”-1.0

As Mars passes perigee, its position will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 17h07m10s 26°30'S Ophiuchus -2.3 20.5"

The coordinates above are given in J2000.0.

The sky on 16 Dec 2025

The sky on 16 December 2025
Sunrise
06:48
Sunset
16:44
Twilight ends
18:13
Twilight begins
05:18


Waning Crescent

8%

26 days old

Planets
Rise Culm. Set
Mercury 05:21 10:27 15:33
Venus 06:28 11:24 16:21
Moon 04:01 09:06 14:06
Mars 07:20 12:12 17:05
Jupiter 18:44 01:49 08:55
Saturn 12:02 17:54 23:45
All times shown in PST.

Source

The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

23 Jun 2285  –  Mars at perigee
21 Jul 2285  –  Mars ends retrograde motion
30 Jul 2287  –  Mars enters retrograde motion
28 Aug 2287  –  Mars at perigee

Image credit

© NASA/Hubble Space Telescope

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