Mercury at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Mercury

Mercury will reach half phase in its Jun–Jul 2147 morning apparition. It will be shining brightly at mag -0.1.

From Fairfield , this apparition will not be one of the most prominent and very difficult to observe, reaching a peak altitude of 12° above the horizon at sunrise on 25 Jun 2147.

Jun–Jul 2147 morning apparition of Mercury

22 May 2147 – Mercury at inferior solar conjunction
17 Jun 2147 – Mercury at greatest elongation west
22 Jun 2147 – Mercury at dichotomy
24 Jun 2147 – Mercury at highest altitude in morning sky
17 Jul 2147 – Mercury at superior solar conjunction

A graph of the phase of Mercury is available here.

Apparitions of Mercury

08 Jan 2147 – Evening apparition
17 Feb 2147 – Morning apparition
29 Apr 2147 – Evening apparition
17 Jun 2147 – Morning apparition
27 Aug 2147 – Evening apparition
09 Oct 2147 – Morning apparition
22 Dec 2147 – 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 04h23m40s 18°49'N Taurus 7.2"
Sun 05h57m 23°25'N Taurus 31'28"

The coordinates above are given in J2000.0.

The sky on 2 May 2024

The sky on 2 May 2024
Sunrise
05:46
Sunset
19:51
Twilight ends
21:38
Twilight begins
03:59


Waning Crescent

33%

24 days old

Planets
Rise Culm. Set
Mercury 04:58 11:17 17:36
Venus 05:31 12:15 19:00
Moon 03:01 08:06 13:21
Mars 04:14 10:15 16:16
Jupiter 06:26 13:36 20:46
Saturn 03:43 09:22 15:00
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

17 Jun 2147  –  Mercury at greatest elongation west
24 Jun 2147  –  Mercury at highest altitude in morning sky
16 Aug 2147  –  Mercury at highest altitude in evening sky
27 Aug 2147  –  Mercury at greatest elongation east

Image credit

© NASA/JPL/MESSENGER

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