JUPITER’S MOONS MAY
Using a small scope you’ll be able to spot Jupiter’s biggest moons. Their positions change dramatically during the month, as shown on the diagram. The line by each date on the left represents 00:00 UT. Mercury
Mercury is not well positioned this month, appearing as a morning object barely creeping above the eastnortheast horizon at sunrise.
Venus
Best time to see: 31 May, 22:00 BST (21:00 UT) Altitude: 16º Location: Gemini Direction: West-northwest Over recent weeks Venus has become a familiar sight in the western sky after sunset and this is set to continue throughout May. The planet’s position does become slightly less optimal throughout the month owing to the decreasing angle between the horizon and the ecliptic. However, this is offset to a degree by Venus increasing its apparent distance from the Sun. At mag. –3.8, Venus appears very bright and able to shine through even bright dusk skies. On 17 May, Venus will appear 5° north of a lovely 7%-lit waxing crescent Moon. On 21 May, Venus appears less than a degree from the open cluster M35 in Gemini. Sadly, the bright evening twilight will reduce the visibility of this mag. +5.5 cluster. By 31 May, Venus will set nearly three hours after the Sun. When viewed through a telescope on this date the planet presents a 13 arcsecond disc, 80% illuminated.
Mars
Best time to see: 31 May, 03:30 BST (02:30 UT) Altitude: 12º (Low) Location: Sagittarius Direction: South-southeast Mars is a morning object in Sagittarius at the start of the month and looks impressively bright – its magnitude now in negative values. On 1 May it shines away at mag. –0.4. Telescopically at the start of the month, it shows an 11-arcsecond disc, easily large enough to reveal surface detail. On 6 May, a 68%-lit waning gibbous Moon lies very close to Mars. The Red Planet crosses the border from Sagittarius into Capricornus mid-month, increasing in brightness all the while. By 31 May, Mars shines at mag. –1.2, appearing like a magnificent orange star amongst the dimmer stars that make up the triangular constellation of Capricornus. The planet’s size is also on the increase so that by 31 May it will look 15 arcseconds across when viewed through a telescope.
Saturn
Best time to see: 31 May, 02:40 BST (01:40 UT) Altitude: 14º Location: Sagittarius Direction: South Saturn appears like a yellowish, mag. +0.7 star to the north of the Teapot asterism in Sagittarius at the start of the month. This is a good time to try and get a telescopic view of Saturn as its rings are currently nicely presented. From the UK, Saturn’s altitude is challenged owing to it being in a position that keeps it low in the south. A bright gibbous Moon flits from the west to the east of Saturn on the mornings of 4 and 5 May. By the end of the month, mag. +0.6 Saturn makes it to a position due south in relative darkness. This brings Saturn to its highest point in the sky, which, from the UK at least, isn’t that impressive. At its best, from the centre of the UK, Saturn only manages to attain a peak altitude of 14°.
On the evening of 31 May, the Moon makes a second visit to the planet. Look out for the sight of a 94%-lit waning gibbous Moon sitting 50 arcminutes to the north of Saturn on this date. Not visible this month: Uranus, Neptune