None available.

Mercury at inferior solar conjunction

Dominic Ford, Editor
From the Inner Planets feed

Objects: Mercury
Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
The sky at

Mercury will pass very close to the Sun in the sky as its orbit carries it between the Sun and Earth.

This occurs once in every synodic cycle of the planet (116 days), and marks the end of Mercury's apparition in the evening sky and its transition to become a morning object over the next few weeks.

At closest approach, Mercury will appear at a separation of only 1°38' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare.

Mercury will also pass perigee – the time when it is closest to the Earth – at around the same time, since it will lie on exactly the same side of the Sun as the Earth in the Solar System. It will move to within a distance of 0.57 AU from the Earth, making it appear with its largest angular size. If it could be observed, it would measure 11.7 arcsec in diameter, whilst appearing completely unilluminated.

The exact position of Mercury at the moment it passes solar conjunction will be:

Object Right Ascension Declination Constellation Angular Size
Mercury 01h49m40s +13°02' Aries 11.7"
Sun 01h52m +11°30' Aries 31'50"

The coordinates above are given in J2000.0.

The sky on 19 April 2017
Twilight ends
Twilight begins

22-day old moon
Waning Crescent


22 days old

Rise Culm. Set
Mercury 06:05 13:08 20:12
Venus 04:49 11:01 17:14
Moon 02:48 07:31 12:14
Mars 07:22 15:03 22:43
Jupiter 18:37 00:23 06:04
Saturn 00:49 05:08 09:26
All times shown in PDT.


Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.


The circumstances of this event were computed using the DE405 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

19 Apr 2017  –  Mercury at inferior solar conjunction
06 May 2017  –  Mercury at aphelion
17 May 2017  –  Mercury at greatest elongation west
23 May 2017  –  Mercury at dichotomy

Image credit

None available.




Color scheme