Here's the latest Night Sky column by Argus astronomy columnist Jonathan Powell.
CHINA has begun trials with the world’s largest array of radio telescopes which, when operational, will monitor the Sun’s activity.
The Daocheng Solar Radio Telescope consists of 313 dishes, forming a circle nearly two miles wide in circumference.
Situated in southwest China, the telescope will continuously survey the Sun, observing solar flares and coronal mass ejections.
The Perseid Meteor Shower
August heralds one of the richest of the annual meteor showers and there are high expectations for 2023, so in preparation, here is your complete guide to the event.
The Perseid shower occurs when the Earth passes through the path of debris left by Comet Swift-Tuttle which last passed closely to our planet in 1992.
Swift-Tuttle, with a nucleus estimated at 16 miles wide, is the largest object in our Solar System to pass the Earth repeatedly, (every 133 years), and as it does so, adds to the debris field already present.
On the nights of peak activity, our planet crosses the densest and dustiest part of the comet’s rubble-strewn orbit, hence the increase in numbers of meteors expected.
There have also been some ‘outburst’ years, (such as in 2016), when the rates have dramatically increased from the expected 100 per hour mark to between 150-200 meteors an hour.
The number of meteors per hour is described in astronomical terms as the Zenith Hourly Rate.
The debris from Comet Swift-Tuttle is made up of mostly sand-size pieces, striking our atmosphere at 133,000 mph per hour, and burning up in a blaze of light across the sky, hence the tag of ‘shooting star’ Different angles of entry and different size pieces generate a variety of meteors brightness’s and trails, or ‘trains’ as they are referred to.
How to watch the Perseid Shower
For the 2023 display, the shower is set to peak in the early hours on the morning of Sunday, August 13 but remember to utilise dates either side of the peak to be virtually guaranteed a good number of meteors.
This year’s display could well be one of the best in years, with no moonlight to interfere by blotting out any of the fainter meteors.
Under perfect conditions, there is the prospect of literally hundreds of meteors to be seen after 1am around peak activity.
Meteors from the shower will radiate from a position high in the north-east.
Once you have spotted a few, you will be able to trace them back to a point in the sky, (the radiant), so that you can finely-tune the direction to view the shower. Remember, you don’t need a telescope or binoculars, all of the display can be seen with the naked eye.
Remember, stay safe, and let someone know where you are be it parent, family member, or guardian.
Want to get more involved with meteors?
All around the world there is a network of cameras looking for meteors all night long as we sleep, and amazing science is being done with the data they collect.
The Global Meteor Network camera systems comprise of a low-cost CCTV camera that is connected to a Raspberry Pi that runs a free piece of open source software called RMS (Raspberry Pi Meteor Station).
The cameras record all night long and the following morning all the potential meteor candidates are analysed.
This first step removes aircraft, satellites, bats, geese, owls, moonlight shining through clouds (and many other things that are not meteors!). The GMN cameras can detect meteors right down to sixth magnitude, which is just at the limit of what the human eye can see from a dark sky location.
The cameras have an approximately 90-degree field of view, so they cover a big chunk of sky as they scout for meteors.
There is a limited amount of science that can be done from meteor events that are only captured on one camera, but as soon as three different cameras capture it from different angles, the event can be triangulated and the real science can begin.
This allows the calculation of the meteor path, where the meteor originated, how fast it was moving, how high it was when it entered the atmosphere, the angle of entry and an estimation of how bright it was. It calculates how large the meteoroid was and taking all the other factors into consideration it will determine if any of the meteoroid survived and landed as a meteorite fall.
Here in the UK most of the GMN cameras are part of the UK Meteor Observation Network. Across the UK we now have almost 250 cameras collecting data.
During the 2022 Perseid Meteor Shower, there were more than 60,000 single camera detections across the UK, with almost 42,500 of them matched with other cameras.
The team behind UKMON have contributed thousands of hours of work, giving their time and software development services for free, but with this quantity of data the computation costs are now totaling about £4,000 a year. The network relies on donations to help towards these costs, but it’s often down to individuals to cover the shortfall.
To donate to UKMON or find out more about becoming involved, visit www.ukmeteornetwork.co.uk.
Super Blue Moon
On August 2, the Moon reached a position known as ‘perigee’. Perigee is the point during the Moon’s elliptical orbit around Earth when it comes closest to us. The full Moon occurring earlier this week, coupled with perigee, will make for a somewhat unscientifically named 'supermoon', whereby the Moon appears 14 per cent larger in our skies, and 25 per cent brighter when compared to a full Moon at apogee, the farthest point away from the Earth in its orbit.
With a full Moon at the start of August, there are enough days in the month for a second full Moon to occur.
On Friday, August 31, we have another full Moon and once again our lunar companion will be at perigee.
This will make for a second supermoon and indeed the closest supermoon of the four to present themselves during 2023.
The variance in appearance and brightness will be on a par with the first supermoon of the month.
As this is the second full Moon in one calendar month, it’s also dubbed a ‘Blue Moon’ for a Super Blue Moon. The first supermoon occurred in July when the Moon was 224,895 miles distant. The second being at the start of August with the Moon 222,158 miles distant. The third and closest is late August with the Moon 222.043 miles distant. The final supermoon of the year will be in September with the Moon 224,658 miles distant.
The phrase ‘Once in a blue moon’ is commonly used to describe a rare event but the occurrence of two full Moon’s in one month, (from which the phrase is derived), isn’t that uncommon. Atmospheric conditions have in the past turned the Moon blue. When Krakatoa erupted in 1883, the volcanic ash that was produced gained high altitude with the subsequent particles acting as filters for sunlight, and on this occasion, the Moon turned a distinct blue and green.
Stars and constellations for beginners
As a help to beginners to find their way around the night sky, use the Moon during August to try and pick out some of the more notable stars on view.
On Thursday, August 10, the Moon is positioned to the north of Aldebaran, the brightest star in the constellation of Taurus, the Bull.
On Sunday, August 13, the Moon is positioned to the south of the brightest star in Gemini, the Twins.
On Wednesday, August 16, the Moon is positioned to the north of Regulus, the brightest star in Leo, the Lion.
On Monday, August 21, the Moon is positioned to the north of Spica, the brightest star in Virgo, the Virgin.
On Friday, August 25, the Moon is positioned to the north of Antares in Scorpius, the Scorpion.
Planets
The two outer planets, Jupiter and Saturn take centre-stage during August.
Jupiter, rising about 11pm, will dominate the night sky this month. In the early hours of the morning on Tuesday, August 8, there will be a lovely pairing of Jupiter right next to the Moon.
On the following morning, the Moon will be positioned between the Pleiades, (Seven Sisters), and Jupiter.
Saturn will be visible all night long during the last month of summer, reaching its closest point to the Earth, (opposition), on Sunday, August 27. In the early hours of the morning on Thursday, August 31, the Moon will be positioned near to Saturn.
Moon Phases
Third Quarter August 8; New Moon August 16; First Quarter August 24; Full Moon August 31.
Sunrise/sunset times
- Start of August: Sun rises at 5.34am. Sets at 9pm.
- End of August: Sun rises at 6.22am. Sets at 8.01pm.
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