Mercury at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Mercury

Mercury will reach half phase in its Feb–Mar 2143 evening apparition. It will be shining brightly at mag -0.5.

From Columbus , this apparition will be well placed but tricky to observe, reaching a peak altitude of 16° above the horizon at sunset on 17 Mar 2143.

Feb–Mar 2143 evening apparition of Mercury

17 Feb 2143 – Mercury at superior solar conjunction
15 Mar 2143 – Mercury at dichotomy
16 Mar 2143 – Mercury at highest altitude in evening sky
16 Mar 2143 – Mercury at greatest elongation east
02 Apr 2143 – Mercury at inferior solar conjunction

A graph of the phase of Mercury is available here.

Apparitions of Mercury

13 Sep 2142 – Morning apparition
24 Nov 2142 – Evening apparition
02 Jan 2143 – Morning apparition
16 Mar 2143 – Evening apparition
30 Apr 2143 – Morning apparition
12 Jul 2143 – Evening apparition
27 Aug 2143 – Morning 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 00h35m30s 5°50'N Pisces 7.1"
Sun 23h31m 3°03'S Pisces 32'11"

The coordinates above are given in J2000.0.

The sky on 22 Nov 2024

The sky on 22 November 2024
Sunrise
07:23
Sunset
17:10
Twilight ends
18:45
Twilight begins
05:47


Waning Crescent

44%

21 days old

Planets
Rise Culm. Set
Mercury 09:15 13:45 18:15
Venus 10:48 15:18 19:49
Moon 22:59 06:12 13:13
Mars 21:34 04:54 12:13
Jupiter 18:09 01:32 08:56
Saturn 13:47 19:20 00:53
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

02 Jan 2143  –  Mercury at greatest elongation west
16 Mar 2143  –  Mercury at highest altitude in evening sky
16 Mar 2143  –  Mercury at greatest elongation east
30 Apr 2143  –  Mercury at highest altitude in morning sky

Image credit

© NASA/JPL/MESSENGER

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