Posts Tagged ‘Venus’


Elongation is a term applied to Mercury and Venus.

When seen from Earth, the two inferior planets appear to become closer or further away from the Sun as they move round their orbits. When either planet reaches its greatest angular distance from the Sun, they are said to have reached eastern (or western) elongation.

Elongation is not a fixed point in their orbits as it is an observational factor that depends on where the Earth is in its orbit as well as the position of Mercury and Venus in theirs.

Black Drop

An appearance seen at the end of second contact and at the start of third contact of a transit of Venus. As the planet moves across the Sun’s disc it seems to draw a strip of blackness after it.  It makes measurement of the exact time of these contacts difficult to measure accurately.

The black drop has been known since telescopic observation of the transits of Venus and Mercury began with several explanations put forward. It now appears, according to the AAS, that is is a combination of the Sun’s limb darkening and the telescope that produces this effect.


Ashen Light

When the plant Venus appears as a crescent, the night side sometimes appears dimly luminous. This is the Ashen light, also known as the Ashen Glow.

It is one of the many unexplained mysteries of the Solar system. It was first noted by an Italian astronomer Giovanni Battista Riccioli way back in 1643 and has been seen by many astronomers since – including Big Bill (Herschel). professionals operating the Keck telescope and of course the late great Patrick Moore. No photographic images exist of the Ashen Light and many professional astronomers have never seen this phenomenon, however, it is accepted as being a genuine thing.

Various theories have been proposed to explain the Ashen Light including atmospheric ionisation, lightning and Venusian inhabitants either carrying out slash and burn agriculture or celebrating the crowning of a new ruler!

This article by Jenny Winder sums it all up nicely

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