Skywatchers in the UK looking to the south-southwest at dusk on Monday, 17 September can see the waxing gibbous Moon just 1¾ degrees to the upper left of Saturn, the pair fitting comfortably in the same field of view of binoculars and small telescopes magnifying 25× or less. This is also a good night for spotting Titan, Saturn’s largest and brightest moon.
Mars may be almost four weeks past opposition, but it’s still an imposing sight low in the southern sky around local midnight. But if you are in any doubt about identifying the Red Planet, the waxing gibbous Moon acts as a convenient celestial guide late into the UK night of Thursday, 23 August. See both the Moon and the Red Planet in the same field of view of low-power binoculars.
Mercury attains its maximum westerly elongation from the Sun on 26 August, meaning that the innermost planet is currently well placed for observation from the UK and Western Europe in the eastern sky around 40 minutes before sunrise. In addition to those in the evening sky, you might just see all five bright naked-eye planets this month!
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.
Skywatchers in Western Europe looking at the rising 13-day-old gibbous Moon in the south-southeast at dusk on Sunday, 27 May can also see prime-time Jupiter within the same binocular field of view. But look closer in the vicinity of the solar system’s largest planet and you’ll see an easily resolved double star – alpha Librae.
Although Jupiter close to opposition may be stealing the other naked-eye planets’ thunder, there’s lots more to see if you’re an early riser on the weekend of 5–6 May. About an hour before sunrise finds Mars and Saturn less than the span of an outstretched hand at arm’s length apart in the UK southern sky, with the waning gibbous Moon acting as a convenient guide to each planet on successive mornings.
Have you ever seen the closest planet to the Sun? If you wish to tick Mercury off your To-See list, particularly if you live in the Southern Hemisphere, now until the middle of May is the time to be scrutinising the eastern sky about an hour before sunrise. Mercury also has a close encounter with an old crescent Moon on 14 May.
Observers in Western Europe should try to locate Venus low in the western sky an hour after sunset. The 3-day-old slim crescent Moon acts as a convenient guide, located some 12½ degrees (or half the span of an outstretched hand at arm’s length) to the upper left of the brightest planet on 18 April. Prominent star Aldebaran lies in the same low-power binocular field of view as the Moon too.
Early risers will already be aware that there’s currently a lot of planetary activity in the morning sky, but at dawn in Western Europe on Monday, 2 April, Mars and Saturn will be just 1¼ degrees apart and seen in the same field of view of telescopes at 30x magnification. The waning Moon is close by on the mornings of 7 & 8 April too.