Venus at dichotomy

Dominic Ford, Editor
From the Inner Planets feed


Objects: Venus

Venus will reach half phase in its 1977 morning apparition. It will be shining brightly at mag -4.3.

From Cambridge , this apparition will not be one of the most prominent but prominent, reaching a peak altitude of 33° above the horizon at sunrise on 6 Aug 1977.

1977 morning apparition of Venus

06 Apr 1977 – Venus at inferior solar conjunction
08 May 1977 – Venus at greatest brightness
14 Jun 1977 – Venus at greatest elongation west
15 Jun 1977 – Venus at dichotomy
05 Aug 1977 – Venus at highest altitude in morning sky
22 Jan 1978 – Venus at superior solar conjunction

A graph of the phase of Venus is available here.

Apparitions of Venus

18 Jun 1975 – Evening apparition
06 Nov 1975 – Morning apparition
24 Jan 1977 – Evening apparition
14 Jun 1977 – Morning apparition
29 Aug 1978 – Evening apparition
18 Jan 1979 – Morning apparition
04 Apr 1980 – Evening 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 02h31m10s 11°58'N Aries 23.6"
Sun 05h38m 23°20'N Taurus 31'29"

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

44%

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

14 Jun 1977  –  Venus at greatest elongation west
06 Aug 1977  –  Venus at highest altitude in morning sky
11 Jun 1978  –  Venus at highest altitude in evening sky
29 Aug 1978  –  Venus at greatest elongation east

Image credit

© NASA/Ricardo Nunes

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