Mars at perigee

Dominic Ford, Editor
From the Outer Planets feed


Objects: Mars

1997 apparition of Mars

05 Feb 1997 – Mars enters retrograde motion
16 Mar 1997 – Mars at opposition
20 Mar 1997 – Mars at perigee
27 Apr 1997 – Mars ends retrograde motion

Mars's orbit around the Sun will carry it to its closest point to the Earth – its perigee – passing within 0.66 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 14.2 arcsec at closest approach, and a maximum brightness of magnitude -1.3 .

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 18:20 (PST), 9° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 23:45, 61° above your southern horizon. It will continue to be observable until around 05:21, when it sinks below 7° above your western horizon.

A chart of the path of Mars across the sky in 1997 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
05 Jan 199712h07m50s2°08'N8.4”0.4
19 Jan 199712h20m50s1°04'N9.6”0.1
02 Feb 199712h27m00s0°45'N10.9”-0.3
16 Feb 199712h24m40s1°18'N12.3”-0.7
02 Mar 199712h13m00s2°44'N13.5”-1.0
16 Mar 199711h54m10s4°39'N14.2”-1.3
30 Mar 199711h34m10s6°22'N14.0”-1.1
14 Apr 199711h19m50s7°16'N13.0”-0.8
28 Apr 199711h14m30s7°09'N11.8”-0.5
12 May 199711h18m20s6°09'N10.5”-0.2
26 May 199711h29m20s4°27'N9.5”0.1

As Mars passes perigee, its position will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
Mars 11h49m10s 5°06'N Virgo -1.3 14.2"

The coordinates above are given in J2000.0.

The sky on 31 Jan 2026

The sky on 31 January 2026
Sunrise
06:47
Sunset
17:20
Twilight ends
18:46
Twilight begins
05:21


Waxing Gibbous

99%

13 days old

Planets
Rise Culm. Set
Mercury 07:20 12:35 17:50
Venus 07:14 12:29 17:45
Moon 16:14 23:34 06:45
Mars 06:36 11:43 16:50
Jupiter 15:11 22:20 05:28
Saturn 09:09 15:04 21:00
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

20 Mar 1997  –  Mars at perigee
27 Apr 1997  –  Mars ends retrograde motion
18 Mar 1999  –  Mars enters retrograde motion
24 Apr 1999  –  Mars at opposition

Image credit

© NASA/Hubble Space Telescope

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