The July 2018 Night Sky

Welcome to the July night-sky. The gas giant planet Jupiter is still well visible high in the southwest in the late evenings. It can be seen shining with bright steady yellowish light. It’s also easy to identify the four major moons through a strong pair of binoculars.

The ringed planet Saturn has just passed opposition in the constellation of Sagittarius. It is fainter than Jupiter and it also shines as a yellowish star that doesn’t twinkle. Through any small telescope, the rings of Saturn are an amazing sight.

The brilliant planet Venus is still around over in the west during the early evening and, on July 15, the thin crescent Moon will be seen close to Venus. Four days later, on the evening of July 19, the Moon will have moved across the sky to be just above Jupiter. Five days after that, on the evening of July 24, the nearly-full Moon will be just above Saturn.

The red planet Mars comes to opposition on the 27th in the constellation of Capricorn. This means that Mars will be closer to the Earth and, therefore, much brighter than in previous months. The orbit of Mars is not circular and its distance from the Sun varies considerably. Now it is closer to the Sun than on average and this can cause planetwide dust storms on Mars. When this happens, very little detail can be seen on the surface of the planet even with a large telescope.

These dust storms can last many days or even weeks. The Mars rovers that are solar-powered will not be able to operate during these conditions.

Also, in the early evening of July 27, there is a total lunar eclipse visible from our part of the world. This eclipse is unusual because as the Sun sets in the northwest on July 27, the already eclipsed full Moon rises in the southeast. This will be quite dramatic as the full Moon passes through the centre of the Earth shadow, so it will be a blood red colour as it slowly rises higher in the evening sky.

The Moon is at last quarter on the 6th, new on the 13th, first quarter on the 19th and full on July 27.

By Clive Jackson
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Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
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To see the July Sky Map click on the pdf link below