Venus at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Venus

Venus will reach half phase in its 1997–1998 evening apparition. It will be shining brightly at mag -4.4.

From Cambridge , this apparition will not be one of the most prominent but , reaching a peak altitude of 21° above the horizon at sunset on 13 Dec 1997.

1997–1998 evening apparition of Venus

02 Apr 1997 – Venus at superior solar conjunction
05 Nov 1997 – Venus at dichotomy
05 Nov 1997 – Venus at greatest elongation east
12 Dec 1997 – Venus at highest altitude in evening sky
14 Dec 1997 – Venus at greatest brightness
16 Jan 1998 – Venus at inferior solar conjunction

A graph of the phase of Venus is available here.

Apparitions of Venus

13 Jan 1995 – Morning apparition
31 Mar 1996 – Evening apparition
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

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 17h59m20s 26°59'S Sagittarius 24.7"
Sun 14h41m 15°41'S Libra 32'15"

The coordinates above are given in J2000.0.

The sky on 22 Nov 2024

The sky on 22 November 2024
Sunrise
06:41
Sunset
16:16
Twilight ends
17:55
Twilight begins
05:02


Waning Crescent

46%

21 days old

Planets
Rise Culm. Set
Mercury 08:36 12:57 17:19
Venus 10:09 14:31 18:53
Moon 22:03 05:23 12:29
Mars 20:40 04:06 11:33
Jupiter 17:14 00:45 08:16
Saturn 13:02 18:32 00:03
All times shown in EST.

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

06 Sep 1996  –  Venus at highest altitude in morning sky
05 Nov 1997  –  Venus at greatest elongation east
13 Dec 1997  –  Venus at highest altitude in evening sky
23 Feb 1998  –  Venus at highest altitude in morning sky

Image credit

© NASA/Ricardo Nunes

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