Transit Observer

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Applets Venus Conjunctions 1631 1639 1761 1769 1874 1882 2004

Deutsch Transit Observer

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The applet displays the positions of the Sun and the planet Venus or Mercury for any location, date, and time.
You may also observe transits of Venus or Mercury.

World map Copyright Apple Computer, Inc.

Change background image

Check out the transit of Venus on 2004, June 8,
or the transit of Mercury on 2003, May 7 !
Select "Venus" or "Mercury from the menu and press the button "Watch Transit"

Watch animation

Applet "Transit Motion"

Planet Applet

Select your location from the menu list, enter the coordinates manually (press return key), or simply click into the word map. The applet will adjust the timezone. As there are no definite rules for daylight saving time, check the time offset to get the correct local times.
The applet is using the most important terms from the VSOP87 theory,
as given in Jean Meeus: "Astronomical Algorithms".

You may use the keys "h", "d", "m" to increase the hour, date, or month,
or Shift key and "h", "d", "m" to decrease the hour, date, or month !

In the horizon view the disc of the Sun is enlarged by a factor of 20. Therefore the image of Venus or Mercury within the Sun's disc does nor necessarily mean a transit (e.g. 2004, June 7) !

For phase angles greater than 90° (esp. at inferior conjunction) the circle line of the planet is painted black.
For phase angles smaler than 90° (esp. at superior conjunction) the circle line of the planet is painted red, and a transit can't occur.

Left: 2002, Jan. 14
superior conjunction, no transit !

Details:
Inferior and superior conjunctions
Phases of Venus

Details:

Elongation Angle, Phase Angle, Magnitude

The checkbox activates a zoom function showing the Sun and the distance of Mercury or Venus from the sun's center at a scale of 2 pixels per arcminute, and indicates a transit if happening.

Some data are written to the browsers
Java Console

Venus as Morning Star
visible before Sunrise Venus as Evening Star
visible after Sunset

In his latest book, Jean Meeus is pointing out that Venus may be seen as evening and morning star (More Mathematical Astronomy Morsels, Willman-Bell, 2002, ISBN 0-943396-74-2).

This may happen when Venus is near to its inferior conjunction:
Paris, March 2001, UT

Date Venus rises Sun height Venus sets Sun height

March 23 05:19 -5.5 19:26 -13.4

March 24 05:14 -6.0 19:19 -13.1

March 25 05:10 -6.3 19:12 -10.7

March 26 05:05 -6.7 19:04 -9.2

March 27 05:00 -7.2 18:57 -7.8

March 28 04:56 -7.5 18:49 -6.3

March 29 04:51 -7.9 18:41 -4.7

March 30 04:46 -8.4 18:34 -3.4

The values (computed by my TransitObserver applet) are taking into account refraction and slightly differ from Meeus'.

The arcus visionis (arc of visibility) of a planet is the depression of the Sun below the horizon, measured on a vertical circle, at the instant when the planet sets (or rises) on the first or last evening (or morning) when it is visible.

Observations were already made in antiquity. The value of the arcus visionis AS is about 6°.

Thus Venus could have been seen in the morning and in the evening on March 24 to 28 !

Venus Elongation Explorer

Transits of venus:

Year Begin End

1518 4 Jun 22:25 5 Jun 5:34

1526 2 Jun 16:10 2 Jun 22:19

1631 7 Dec 3:37 7 Dec 7:04

1639 4 Dec 14:51 4 Dec 22:02

1761 6 Jun 1:55 6 Jun 8:43

1769 3 Jun 19:08 4 Jun 1:42

1874 9 Dec 1:38 9 Dec 6:36

1882 6 Dec 13:48 6 Dec 20:22

2004 8 Jun 5:07 8 Jun 11:33

2012 5 Jun 22:03 6 Jun 4:56

2117 10 Dec 23:54 11 Dec 5:50

2125 8 Dec 13:10 8 Dec 19:01

Updated: 2023, Oct 20

Year	Begin	End
1518	4 Jun 22:25	5 Jun 5:34
1526	2 Jun 16:10	2 Jun 22:19
1631	7 Dec 3:37	7 Dec 7:04
1639	4 Dec 14:51	4 Dec 22:02
1761	6 Jun 1:55	6 Jun 8:43
1769	3 Jun 19:08	4 Jun 1:42
1874	9 Dec 1:38	9 Dec 6:36
1882	6 Dec 13:48	6 Dec 20:22
2004	8 Jun 5:07	8 Jun 11:33
2012	5 Jun 22:03	6 Jun 4:56
2117	10 Dec 23:54	11 Dec 5:50
2125	8 Dec 13:10	8 Dec 19:01