There’s a lot of planetary activity in the dawn sky in mid-April. If you’re an early riser in the British Isles, let the waning crescent Moon be your guide to the naked-eye planets Jupiter, Saturn and Mars on 15 and 16 April 2020. Typical 7×50 or 10×50 binoculars will show these attractive conjunctions well, while the smallest of telescopes also reveal some of Jupiter’s bright Galilean moons.
Innermost planet Mercury puts on its best morning display of the year for Northern Hemisphere observers from late November to early December. Skywatchers in the British Isles should find a location offering an unobstructed view of the southeast horizon about 45 minutes before sunrise to get the best views, with the Red Planet and star Spica – the brightest in Virgo – also nearby.
On 18 June at the end of civil twilight in the UK, planets Mars and Mercury lie slightly less than one-quarter of a degree apart in the constellation of Gemini. Observing this conjunction will be a challenge from the UK as the pair will be just 5 degrees high in the west-northwest at civil dusk in bright twilight, which is about 50 minutes after sunset for London.
On 31 March at 4am BST, Mars passes just 3.1 degrees south of the Pleiades, or Seven Sisters open star cluster in the constellation of Taurus. The Red Planet sets before midnight as seen from the UK, so you should look to the west as darkness falls. Mars and the Pleiades lie within the same field of view of typical 10×50 binoculars from 28 March through 1 April 2019.
Have you ever seen planet Uranus? If skies are clear in the UK and Western Europe on the evening of Sunday, 10 February, see this icy gas giant less than 2 degrees (or four lunar diameters) from Mars and 6 degrees from the 5-day-old crescent Moon. In fact, you’ll see all three in a single view of wide-angle binoculars like 7×50s.
Observers should direct their gaze to the southern sky at dusk on Saturday, 12 January to view the 6-day-old waxing Moon in the constellation of Pisces. Look a little closer around 6pm GMT in the UK this night to see Mars as a magnitude +0.6 orange-coloured ‘star’ above the lunar crescent. If you own wide-angle 7× or 8× binoculars, you can see the Moon and Red Planet in the same field of view.
Observers in the British Isles looking due south close to 6pm GMT on Friday, 7 December will find magnitude +0.1 planet Mars about 30 degress, or a span and a half of an outstretched hand at arm’s length, above the horizon. What you won’t see unless you have binoculars or a small telescope is that magnitude +7.9 outermost planet Neptune lies just one-tenth of a degree from the Red Planet.
If clear skies persist, observers in the UK can view four naked-eye planets between now and the end of the month. Brightest planet Venus is visible low in the west some 45 minutes after sunset, while the waxing Moon is your celestial pointer to Jupiter, Saturn and Mars between 21 and 28 July at midnight.
Friday, 27 July sees the second total lunar eclipse of 2018, which also happens to be the longest of the 21st century. Observers in Antarctica, Australasia, Russia, Asia, Africa, Scandanavia, Europe, Central and Eastern South America will see the event. The Moon rises at mid-eclipse as seen from the British Isles, some 6 degrees north of Mars at opposition.