Venus at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Venus

Venus will reach half phase in its 1999 evening apparition. It will be shining brightly at mag -4.3.

From Cambridge , this apparition will be well placed and prominent, reaching a peak altitude of 36° above the horizon at sunset on 10 May 1999.

1999 evening apparition of Venus

29 Oct 1998 – Venus at superior solar conjunction
10 May 1999 – Venus at highest altitude in evening sky
10 Jun 1999 – Venus at dichotomy
11 Jun 1999 – Venus at greatest elongation east
17 Jul 1999 – Venus at greatest brightness

A graph of the phase of Venus is available here.

Apparitions of Venus

20 Aug 1996 – Morning apparition
05 Nov 1997 – Evening apparition
27 Mar 1998 – Morning apparition
11 Jun 1999 – Evening apparition
30 Oct 1999 – Morning apparition
17 Jan 2001 – Evening apparition
07 Jun 2001 – Morning apparition

Observing Venus

Venus'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 a few months each time it reaches greatest separation from the Sun – moments referred to as greatest elongation. These apparitions repeat roughly once every 1.6 years.

On these occasions, Venus is so bright and conspicuous that it becomes the third brightest object in the sky after the Sun and Moon. It is often called the morning star or the evening star.

Venus's phase

Venus'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.

Venus 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 Venus's orbit is not quite perfectly aligned with the ecliptic.

Venus's position

The coordinates of Venus when it reaches dichotomy will be:

Object Right Ascension Declination Constellation Angular Size
Venus 08h31m20s 21°15'N Cancer 23.4"
Sun 05h14m 23°01'N Taurus 31'30"

The coordinates above are given in J2000.0.

The sky on 30 Apr 2024

The sky on 30 April 2024
Sunrise
05:38
Sunset
19:42
Twilight ends
21:32
Twilight begins
03:49


Waning Gibbous

51%

22 days old

Planets
Rise Culm. Set
Mercury 04:53 11:13 17:32
Venus 05:22 12:05 18:48
Moon 01:45 06:07 10:35
Mars 04:10 10:09 16:07
Jupiter 06:21 13:33 20:46
Saturn 03:43 09:20 14:58
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 May 1999  –  Venus at highest altitude in evening sky
11 Jun 1999  –  Venus at greatest elongation east
25 Oct 1999  –  Venus at highest altitude in morning sky
30 Oct 1999  –  Venus at greatest elongation west

Image credit

© NASA/Ricardo Nunes

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