Being high summer the nights are short and not particularly dark making observations difficult or in some cases impossible. It is however an opportunity to look for noctilucent clouds (pictured above) and Zodiacal Light. Vernon from the Callander and West Perthshire U3A Astronomy group shares what to look out for this month.
It is always helpful to have a star chart to follow when navigating and observing the heavens. A free star chart which also contains lots of additional observational notes is published monthly by Skymaps. Simply go to skymaps.com and scroll down to ‘Download the latest issue’. From here you will can download the northern hemisphere version and save it. This is then best printed double sided to an A4 sheet. It is worth noting that planets do not appear on skymaps. In this note of astronomical events I have only included items that can be seen either with the naked eye or with a pair of binoculars.
Should you venture outside you will need a torch. Use a red light head torch if you have one, or put red plastic over a torch to illuminate the skymap and preserve your night vision which improves greatly over time. Wrap up warm and with a little perseverance, about 20 minutes, you will feast your eyes on the universe that you live within. Enjoy and indulge!
Now it is time to look out for Noctilucent Clouds and Zodiacal Light. Noctilucent Clouds are clouds of icy dust that form at high altitude on the edge of space, around 80km high, when temperatures and pressures in the upper atmosphere are exactly right. The Noctilucent Light season is between the end of May and early August every year. These night-shining clouds appear from around an hour after sunset to an hour before sunrise and look spectacular. Look towards the north for light blue wispy clouds illuminated in the twilight.
Zodiacal light is best observed in the western sky in the spring after the evening twilight has completely disappeared, or in the eastern sky in the autumn just before the morning twilight appears. The zodiacal light appears as a column, brighter at the horizon, tilted at the angle of the ecliptic. The light scattered from extremely small dust particles is strongly forward scattering, although the zodiacal light actually extends all the way around the sky, hence it is brightest when observing at a small angle with the Sun
Persistent twilight makes observations in the southern sky particularly difficult. The blood-red supergiant star Antares, whose name means ‘Rival to Mars’, is in the large and bright constellation of Scorpius slightly east of south low in the sky. Scorpius is one of the oldest constellations with references in the earliest astronomical records. Higher above Scorpius is Ophiuchus, the Serpent Bearer. Ophiuchus, a large equatorial constellation can be readily located as it sits between the bright stars of Altair, in Aquilla, to the east and Spica, in Virgo, to its west. Since Roman times Ophiuchus has been seen as ‘Asclepius’, the god of healing, who traditionally carried a staff with a snake wound about it and sometimes called the “thirteenth sign of the zodiac”. Higher still in the sky sits the more familiar constellations of Bootes, Corona Borealis and Hercules which are better placed now than at any other time of the year for observation.
As June is the month containing the summer solstice, 21st, here in Scotland the sky remains so light that nearly all of the feinter stars and constellations are invisible. Even the bright stars forming the Plough in Ursa Major, the Great Bear, can be difficult to locate except around midnight. This is the time to search for Noctilucent clouds described earlier.
Tau Herculids, in the Constellation of Hercules, give an occasional display between 19th May and 19th June, peaking on 9th June, but are generally at a very low rate per hour. The parent comet is 73P Schwassmann-Wachmann
Mercury leaves us into the west at the beginning of the month going into inferior conjunction, that is, it is directly in line between Earth and the Sun, on11th June, reappearing in the east at sunrise later in the month. Its brightness varies from 6th magnitude to 1st magnitude by the end of the month, continuing to brighten as we enter July.
Venus continues to be very low on the horizon, around 10 degrees, at magnitude -3.9.
Earth experiences an annular solar eclipse (partial solar eclipse in the UK) on the 10th June. This partial solar eclipse in the UK will drop us into a period of shade with around 40% of the sun covered in the Central belt of Scotland, 50% in the far north and around 30% in Devon and Cornwall. The dark skies either side of the eclipse will improve the Tau Herculid meteor shower. Solstice is on 21st when the Sun reaches its most northerly declination of the year marking the beginning of summer in the northern hemisphere and the onset of winter in the south.
Mars continues in the evening sky setting earlier into the twilight each night.
Jupiter is our bright morning planet rising around 5 hours before sunrise by the end of the month.
Saturn also an early morning planet. Saturn’s rings are becoming more difficult to observe as the months pass. The tilt of its rings is closing and the planet is looking smaller.
Nights of particular interest
Some of the objects described below are expressed in degrees from the Moon. This is far less complicated to measure than you might think. To measure 10 degrees, hold your hand up towards the sky at arm’s length and turn your hand up so that it obscures part of your view. The width of your hand is 10 degrees and holding just one finger is two degrees.
2nd June 07.45 Moon last quarter (morning sky)
3rd June 01.06 Neptune 4.5 degrees north of the Moon
5rh June 01.30 Jupiter rises, shadows of Io and Ganymede can be seen on planet until 03.15hrs.
7th June 06.16 Uranus 2.3 degrees north of the Moon
8th June This is the darkest night of the month for observing
9th June Peak of Meteor shower Tau Herculids.
10th June 10.53 New Moon (not visible)
10th June 00.15 Jupiter rises, Callisto transits until 02.30
10thJune 10.06–11.24 Partial eclipse of the Sun. 40% coverage at 11.13hrs. Never look directly towards the Sun. There is no pain but permanent scarring and damage can occur.
12th June 06.42 Venus 1.5 degrees south of the Moon, Mars 4 degrees above to the left.
15th June 23.59 Regulus, constellation of Leo, 5 degrees south of the Moon
18th June 03.54 Moon, first quarter (evening sky)
19th June 22.09 Spica, constellation of Virgo, 6.5 degrees south of the Moon
21st June 03.32 Summer Solstice
22nd June 22.15 Venus and Mars with Castor and Pollux close to WNW horizon
23rd June 03.46 Antares, constellation of Scorpio, 4.8 degrees south of the Moon
23rd June 09.55 Moon at perigee, 359.956 km form Earth
24th June 18.40 Full Moon (visible all night)
27th June 04.00 Jupiter and Saturn are to the right of the Moon, 20 degrees above the southern horizon.