Venus at greatest brightness

Dominic Ford, Editor
From the Inner Planets feed


Objects: Venus

Venus will reach its greatest brightness in its 1999–2000 morning apparition. It will be shining brightly at mag -4.6.

From Cambridge , this apparition will be well placed and prominent, reaching a peak altitude of 41° above the horizon at sunrise on 25 Oct 1999.

1999–2000 morning apparition of Venus

20 Aug 1999 – Venus at inferior solar conjunction
25 Sep 1999 – Venus at greatest brightness
25 Oct 1999 – Venus at highest altitude in morning sky
29 Oct 1999 – Venus at dichotomy
30 Oct 1999 – Venus at greatest elongation west

A graph of the brightness of Venus is available here.

Apparitions of Venus

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
21 Aug 2002 – 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 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 09h33m20s 9°45'N Leo 38.6"
Sun 12h07m 0°46'S Virgo 31'53"

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

54%

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

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
17 Jan 2001  –  Venus at greatest elongation east

Image credit

© NASA/Ricardo Nunes

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