© NASA/JPL/MESSENGER

Mercury at aphelion

Dominic Ford, Editor
From the Inner Planets feed

Objects: Mercury
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Mercury's 88-day orbit around the Sun will carry it to its furthest point to the Sun – its aphelion – at a distance of 0.47 AU.

Unlike most of the planets, which follow almost exactly circular orbits around the Sun only varying in their distance from the Sun by a few percent, Mercury has a significantly elliptical orbit.

Its distance from the Sun varies between 0.307 AU at perihelion (closest approach to the Sun), and 0.467 AU at aphelion (furthest recess from the Sun). This variation, of over 50%, means that its surface receives over twice as much energy from the Sun at perihelion as compared to aphelion.

However, this makes little difference to Mercury's telescopic appearance, since little if any detail on its surface can be resolved by ground-based telescopes. Although its changing seasons have an incredible effect upon its surface temperatures, there is little change that is visible to amateur observers.

The position of Mercury at the moment it passes aphelion will be:

Object Right Ascension Declination Constellation Angular Size
Mercury 20h34m10s 20°03'S Capricornus 5.5"
Sun 21h55m 12°40'S Capricornus 32'23"

The coordinates above are given in J2000.0.

From Cambridge, Mercury will not be observable – it will reach its highest point in the sky during daytime and will be no higher than 2° above the horizon at dawn.

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The sky on 15 Feb 2023

The sky on 15 February 2023
Sunrise
06:39
Sunset
17:15
Twilight ends
18:50
Twilight begins
05:04

25-day old moon
Waning Crescent

21%

25 days old

Planets
Rise Culm. Set
Mercury 05:50 10:36 15:21
Venus 07:51 13:42 19:32
Moon 02:59 07:17 11:30
Mars 11:06 18:50 02:35
Jupiter 08:24 14:35 20:47
Saturn 06:50 12:02 17:14
All times shown in EST.

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

30 Jan 2023  –  Mercury at greatest elongation west
11 Apr 2023  –  Mercury at highest altitude in evening sky
11 Apr 2023  –  Mercury at greatest elongation east
29 May 2023  –  Mercury at greatest elongation west

Image credit

© NASA/JPL/MESSENGER

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Cambridge

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Longitude:
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42.38°N
71.11°W
EST

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