Mercury at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Mercury

Mercury will reach half phase in its Jul–Aug 2283 morning apparition. It will be shining brightly at mag -0.3.

From Cambridge , this apparition will be well placed but tricky to observe, reaching a peak altitude of 15° above the horizon at sunrise on 31 Jul 2283.

Jul–Aug 2283 morning apparition of Mercury

05 Jul 2283 – Mercury at inferior solar conjunction
27 Jul 2283 – Mercury at greatest elongation west
30 Jul 2283 – Mercury at highest altitude in morning sky
30 Jul 2283 – Mercury at dichotomy
21 Aug 2283 – Mercury at superior solar conjunction

A graph of the phase of Mercury is available here.

Apparitions of Mercury

13 Feb 2283 – Evening apparition
28 Mar 2283 – Morning apparition
08 Jun 2283 – Evening apparition
27 Jul 2283 – Morning apparition
05 Oct 2283 – Evening apparition
14 Nov 2283 – Morning apparition
28 Jan 2284 – 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 07h00m30s 21°16'N Gemini 7.0"
Sun 08h23m 19°18'N Cancer 31'29"

The coordinates above are given in J2000.0.

The sky on 25 Nov 2024

The sky on 25 November 2024
Sunrise
06:45
Sunset
16:14
Twilight ends
17:54
Twilight begins
05:05


Waning Crescent

22%

24 days old

Planets
Rise Culm. Set
Mercury 08:26 12:49 17:13
Venus 10:11 14:34 18:58
Moon 01:14 07:25 13:26
Mars 20:30 03:57 11:23
Jupiter 17:01 00:31 08:02
Saturn 12:50 18:21 23:51
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

30 Jul 2283  –  Mercury at highest altitude in morning sky
28 Sep 2283  –  Mercury at highest altitude in evening sky
05 Oct 2283  –  Mercury at greatest elongation east
14 Nov 2283  –  Mercury at highest altitude in morning sky

Image credit

© NASA/JPL/MESSENGER

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