© NASA/JPL/MESSENGER

Mercury at dichotomy

Dominic Ford, Editor
From the Inner Planets feed

Objects: Mercury
Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
The sky at

Mercury will reach half phase in its Dec 2143–Jan 2144 morning apparition. It will be shining brightly at mag -0.4.

From Fairfield , this apparition will be well placed but tricky to observe, reaching a peak altitude of 17° above the horizon at sunrise on 15 Dec 2143.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

Dec 2143–Jan 2144 morning apparition of Mercury

28 Nov 2143 – Mercury at inferior solar conjunction
12 Dec 2143 – Mercury at dichotomy
14 Dec 2143 – Mercury at highest altitude in morning sky
16 Dec 2143 – Mercury at greatest elongation west

A graph of the phase of Mercury is available here.

Apparitions of Mercury

12 Jul 2143 – Evening apparition
27 Aug 2143 – Morning apparition
07 Nov 2143 – Evening apparition
16 Dec 2143 – Morning apparition
27 Feb 2144 – Evening apparition
11 Apr 2144 – Morning apparition
23 Jun 2144 – Evening apparition

Observing Mercury

Mercury's orbit lies closer to the Sun than the Earth's, meaning that it always appears close to the Sun and is lost in the Sun's glare much of the time.

It is observable for only a few weeks each time it reaches greatest separation from the Sun – moments referred to as greatest elongation. These apparitions repeat roughly once every 3–4 months.

Mercury's phase

Mercury's phase varies depending on its position relative to the Earth. When it passes between the Earth and Sun, for example, the side that is turned towards the Earth is entirely unilluminated, like a new moon.

Conversely, when it lies opposite to the Earth in its orbit, passing almost behind the Sun, it appears fully illuminated, like a full moon. However, at this time it is also at its most distant from the Earth, so it is actually fainter than at other times.

Mercury shows an intermediate half phase – called dichotomy – at roughly the same moment that it appears furthest from the Sun, at greatest elongation. The exact times of the two events may differ by a few days, only because Mercury's orbit is not quite perfectly aligned with the ecliptic.

Mercury's position

The coordinates of Mercury when it reaches dichotomy will be:

Object Right Ascension Declination Constellation Angular Size
Mercury 15h43m20s 17°03'S Libra 7.3"
Sun 17h07m 22°52'S Ophiuchus 32'28"

The coordinates above are given in J2000.0.

The sky on 28 Mar 2024

The sky on 28 March 2024
Sunrise
06:40
Sunset
19:13
Twilight ends
20:47
Twilight begins
05:06

18-day old moon
Waning Gibbous

85%

18 days old

Planets
Rise Culm. Set
Mercury 07:08 13:57 20:46
Venus 06:08 11:53 17:38
Moon 21:47 02:58 08:00
Mars 05:29 10:52 16:16
Jupiter 08:21 15:22 22:23
Saturn 05:52 11:26 17:00
All times shown in EDT.

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

10 Nov 2143  –  Mercury at highest altitude in evening sky
14 Dec 2143  –  Mercury at highest altitude in morning sky
16 Dec 2143  –  Mercury at greatest elongation west
27 Feb 2144  –  Mercury at greatest elongation east

Image credit

© NASA/JPL/MESSENGER

Share

Fairfield

Latitude:
Longitude:
Timezone:

41.14°N
73.26°W
EDT

Color scheme