What is a Conjunction?

In astronomical terms, a conjunction involves the close approach of two or more solar system bodies or a close approach of a single solar system body with another object in the sky (like a star cluster or bright star).

It’s important to remember that these conjunctions are only from our perspective here on the planet Earth, the objects are never actually close together.  A perfect example is the recent conjunction between the planet Venus and the Pleiades Star Cluster in the constellation Taurus.

The Pleiades actually lie about 440 light years behind Venus in the night sky, but from our perspective they appeared to be side-by-side.

See the basic diagram below to see how a conjunction occurs.

Example of a conjunction involving Venus and the Pleiades cluster.

Example of a conjunction involving Venus and the Pleiades cluster.

 

Conjunctions occur all the time, some spectacular, others routine (and mostly involving the moon).  One of the more spectacular conjunctions is coming up in July 2015 between Venus and Jupiter – we’ll be putting out a special FAE for this event in the coming months.

The photo below was taken using a Canon 6D and 100mm lens, unguided and tripod mounted.  There was a thin layer of clouds at the time the photo was taken, I think it add a nice effect to the photo.

Photo taken by Tom Wildoner on April 12, 2015 of the conjunction of Venus and the Pleiades Star Cluster.

Photo taken by Tom Wildoner on April 12, 2015 of the conjunction of Venus and the Pleiades Star Cluster.

2 Responses to What is a Conjunction?

  1. Aska Meta says:

    Fascinating. Wanted to click the Like-star, but not registered with the website, so will just tell you. Keep up the great work. Thank you for this.

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