Mercury at perihelion

Dominic Ford, Editor
From the Inner Planets feed


Objects: Mercury

Mercury's 88-day orbit around the Sun will carry it to its closest point to the Sun – its perihelion – at a distance of 0.31 AU from the Sun.

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 perihelion will be:

Object Right Ascension Declination Constellation Angular Size
Mercury 18h13m20s 21°52'S Sagittarius 9.8"
Sun 17h52m 23°25'S Sagittarius 32'30"

The coordinates above are given in J2000.0.

From Fairfield, Mercury will not be readily observable since it will be very close to the Sun, at a separation of only 5° from it.

The sky on 20 Dec 2023

The sky on 20 December 2023
Sunrise
07:12
Sunset
16:26
Twilight ends
18:06
Twilight begins
05:32


Waxing Gibbous

65%

8 days old

Planets
Rise Culm. Set
Mercury 07:29 12:10 16:51
Venus 03:56 09:04 14:12
Moon 12:30 18:49 01:19
Mars 06:32 11:07 15:42
Jupiter 13:23 20:09 02:56
Saturn 10:55 16:14 21:33
All times shown in EST.

Warning

Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.

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

08 Dec 2023  –  Mercury at highest altitude in evening sky
07 Jan 2024  –  Mercury at highest altitude in morning sky
12 Jan 2024  –  Mercury at greatest elongation west
24 Mar 2024  –  Mercury at highest altitude in evening sky

Image credit

© NASA/JPL/MESSENGER

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