July ends with a spectacular grouping of celestial objects in the eastern pre-dawn skies. The waning crescent moon will appear with the Pleiades star cluster, the planets Jupiter and Mars, and the bright star Aldebaran for two consecutive mornings.
The chart shows the view looking east from London at 4am BST on 31 July. On this night, the 25-day-old moon will be a thin waning crescent with just 19% of its visible surface illuminated. The night before, the crescent will be larger, and less fragile-looking, but will be more centrally placed, appearing close to Mars.
The grouping takes place in the constellation of Taurus, the bull, with several of the constellation’s stars adding to the spectacle. Aldebaran is a red giant star, fully 45 times the radius of our sun and 400 times more luminous.
The Pleiades is a collection of hundreds of stars, of which a handful are visible to the naked eye. This gives rise to the popular name of the seven sisters. The brightest star in the cluster is Alcyone.
The grouping is also visible from the southern hemisphere, just climbing into the north-eastern sky before the glare of the sunlight washes the spectacle from view.
