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Thursday, 19 July 2018  •  Thursday, 7 Holly Moon 2018

Watching the night sky in Holly Moon 2018

13 July - 11 August 2018

Map of night sky at full moon: 27 July, 20:20 UTC
Northern hemisphere perspective, aligned on the ecliptic. Morning sky to the left, evening to the right.

night sky map for Holly Moon 2018

At full moon on 27 July, there is a total eclipse of the moon, visible from Europe, Africa, Australasia and much of Asia and South America. As seen from NW Europe and SE South America, the moon rises in total eclipse. It is a deep eclipse, with the moon near the middle of Earth’s shadow, and the moon is dark red with the small amount of sunlight refracted through Earth’s atmosphere. As seen from the moon, Earth is a ring of fire. The eclipse starts at 18:14 (17:14 UTC) when the moon enters the partial shadow of Earth, and a partial eclipse starts on the moon. At first, the change is hard to see, but gradually the moon’s eastern limb darkens (the top of the moon as it rises over eastern Europe and down across Africa to Nigeria), and the full shadow touches the edge of the moon at 19:24 (18:24 UTC). The full shadow covers the moon completely, and total eclipse starts, at 20:30 (19:30 UTC). Over London, the moon rises at 20:48, and the sun sets at 20:55. The corresponding times for Glasgow are 21:25 and 21:32 and for Penzance 21:05 and 21:11. The darkest part of the eclipse is at 21:21 (20:21 UTC), and may well be hard to see until the sun sets and the sky itself darkens. Totality ends at 22:13 (21:13 UTC), and the moon leaves the full shadow at 23:19 (22:19 UTC) and the partial (penumbral) shadow at 00:28 (23:28 UTC). As seen from Australasia and eastern Asia, the moon sets and the sun rises during the eclipse, on the morning of 28 July. This is an especially red eclipse, as the very bright red Mars is nearby, to the south of the eclipsed moon. As seen from most of Britain & Ireland, Mars rises below the totally eclipsed moon. [From Cornwall, Mars rises below the moon just before the total eclipse ends.]

The evening sky is full of bright planets, especially after Mars rises and before Venus sets.

Venus shines brightly in the western evening sky all month, albeit low down as seen from the north. At the start of the lunar month, Mercury is in the evening sky too, easily seen below Venus. On 14 July, the new crescent moon is close to Mercury, with Venus above the pair. On 15 July, the moon is between the two, nearer to Venus, and also close to Regulus, the bright star of Leo. As seen from the west coast of North America, the moon passes very close north of Venus that evening. As seen from the northern hemisphere, Mercury slips quickly into the twilight over the next few days. Southern hemisphere viewers can see Mercury above the sunset until about 29 July. Mercury passes this side of the sun on 9 August.

Round to the south, as seen from the northern hemisphere, is bright Jupiter in the constellation Libra. On the evening of 20 July, the moon is close by.

Much further round is the less bright Saturn in the constellation Sagittarius, setting in the early hours. On the night of 24/25 July, the moon is near Saturn, with the west of North America again being especially favoured with a close pass while they are above the horizon.

Mars shines very brightly in the night sky, moving westwards through the southern stars of Capricornus. On 4 July, it surpasses the brightness of Jupiter. On 27 July, it reaches opposition, rising at sunset, and on the night of 30-31 July, it is nearest to Earth, 57.6 million kilometres or 3.2 light minutes away. It is brightest on 27 or 28 July, when it is opposite the sun. The full moon is nearby on the night 27/28 July. Look for Mars during the lunar eclipse, if you’re in the right place, and see it shining red to the south of the deep red moon. After the eclipse is over, the full moon will dampen Mars’ brilliance somewhat. This is one of Mars’ closer passes to Earth. Its oppositions can come at any time of the Earth year, and the nearest ones are when it falls around 27 August on Earth, as in 2003. This is because Mars’ orbit is relatively eccentric, and a 27 August opposition coincides with Mars’ perihelion, its nearest point to the sun.

At dark moon on 11 August, there is a partial eclipse of the sun over the Arctic, much of north and NE Asia, Greenland, Iceland, most of Scandinavia and the far north of Scotland. From Reykjavík, 10% of the sun is covered at 08:46, Lerwick 1.6% and Thurso 0.3% at 09:50 (08:50 UTC), Longyearbyen 35% at 11:18 (09:18 UTC), Stockholm 0.9% at 11:10 (09:10 UTC), Moscow 0.4% at 12:35 (09:35 UTC), Yakutsk 58% at 19:15 (10:15 UTC) and Ulaanbaatar 30% at 18:40 (10:40 UTC). As seen from Beijing, the sun sets during the eclipse.

Look out for the Delta Aquarid meteors on the night 28/29 July, especially after midnight.

The month ahead: Hazel Moon 2018

12 August - 9 September 2018

Map of night sky at full moon: 26 August, 11:56 UTC
Northern hemisphere perspective, aligned on the ecliptic. Morning sky to the left, evening to the right.

night sky map for Hazel Moon 2018

The evening sky is full of bright planets. After sunset, you can see Venus, Jupiter, Saturn and Mars.

Venus is the bright evening star in the west, and on 17 August reaches 45.9° east of the sun. As seen from the southern hemisphere, Venus is very prominent, high up in the north-west, but from northern lands, Venus is quite low in the west. It’s largely to do with our different perspectives on the plane of the solar system east of the sun at this time of year.

As seen from the northern hemisphere, the new crescent moon is to the right of Venus on 13 August, and is above it on the 14th.

Further out from the sun is Jupiter. Over the next few weeks, the two bright planets swing closer together, but do not pass in the sky, as Venus eventually makes it first into the sunset. On the evening of 17 August, the moon is near Jupiter. Between Venus and Jupiter, fairly low in the SW as seen from the northern hemisphere, is Spica, the bright star of Virgo. On 1 September, Venus passes just over a degree south of Spica. By this date, Venus is very bright, as it comes closer to Earth, but it is low down in the south-west, as seen from the north of our planet.

Saturn is much further round towards the east in the early evening, in the constellation Sagittarius. On the evenings of 20 and 21 August, the moon is either side of the ringed planet as seen from Europe and Africa. As seen from East Asia and Australasia, the moon is very close to the north of Saturn on the evening of the 21st.

Mars moves away gradually from its close encounter with Earth, and dims somewhat. On 9 September, Mars is once more less bright than Jupiter. Mars continues to move westwards through the southern part of Capricornus, but Earth has moved away so much that Mars’ natural movement eastwards is slowly resumed on 27 August. The moon is close to Mars on the evening of 23 August. Mars sets during the early hours, and by the end of the month has firmly become an evening sky planet.

On 26 August, Mercury comes to 18.3° west of the sun in the eastern morning sky. It is not a great view from any part of Earth, but the planet may be seen in the dawn for a few days around that date, especially in the northern hemisphere.

The ice giant planet Neptune comes to opposition and closest to Earth on 7 September, 4328 million kilometres or 4.0 light hours way. It is too faint to see with the naked eye, but look for it through binoculars or telescope in the constellation Aquarius, between the stars Lambda and Phi Aquarii.

Look out for the Perseid meteors on the night 12/13 August, especially after midnight.

William Morris
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