Venus will reach its greatest brightness in its 1991 evening apparition. It will be shining brightly at mag -4.5.
From Cambridge , this apparition will be well placed and prominent, reaching a peak altitude of 36° above the horizon at sunset on 11 May 1991.
1991 evening apparition of Venus
| 11 May 1991 | – | Venus at highest altitude in evening sky |
| 13 Jun 1991 | – | Venus at dichotomy |
| 14 Jun 1991 | – | Venus at greatest elongation east |
| 19 Jul 1991 | – | Venus at greatest brightness |
A graph of the brightness of Venus is available here.
Apparitions of Venus
| 22 Aug 1988 | – | Morning apparition |
| 08 Nov 1989 | – | Evening apparition |
| 30 Mar 1990 | – | Morning apparition |
| 14 Jun 1991 | – | Evening apparition |
| 02 Nov 1991 | – | Morning apparition |
| 19 Jan 1993 | – | Evening apparition |
| 10 Jun 1993 | – | 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 brightness
Venus's brightness depends on two factors: its closeness to the Earth, and its phase. Its 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 reaches its brightest when it is still a crescent – with less than half of its disk illuminated. This is because it is much closer to the Earth during its crescent phases than at other times.
As a result, during evening apparitions, Venus reaches maximum brightness a few days after it is at greatest separation from the Sun, which always coincides with it showing half-phase (dichotomy).
Conversely, during morning apparitions, Venus reaches maximum brightness a few days before it is at greatest separation from the Sun.
Venus's position
The coordinates of Venus when it reaches its greatest brightness will be:
| Object | Right Ascension | Declination | Constellation | Angular Size |
| Venus | 10h23m00s | 8°06'N | Leo | 38.9" |
| Sun | 07h54m | 20°49'N | Gemini | 31'28" |
The coordinates above are given in J2000.0.
The sky on 22 Nov 2024
| The sky on 22 November 2024 | ||||||||||||||||||||||||||||||||||
|
44% 21 days old |
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 1991 | – Venus at greatest elongation east |
| 27 Oct 1991 | – Venus at highest altitude in morning sky |
| 02 Nov 1991 | – Venus at greatest elongation west |
| 19 Jan 1993 | – Venus at greatest elongation east |
Image credit
© NASA/Ricardo Nunes