July ends with a spectacular clustering of celestial objects in the eastern pre-dawn sky. The waning crescent moon will appear with the Pleiades star cluster, the planets Jupiter and Mars, and the bright star Aldebaran for two successive 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 moon will be larger and appear less fragile, but will be more centrally located, close to Mars.
The grouping takes place in the constellation 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 are a collection of hundreds of stars, a handful of which are visible to the naked eye. This gives rise to the popular name of the seven sisters. The brightest star in the group is Alcyone.
The cluster is also visible from the southern hemisphere, just rising into the north-eastern sky before the glare of the sunlight washes the spectacle out of view.
