When and how to watch the Perseid meteor shower - and enjoy the grand tour of planets
Comet Neowise might have moved on, but there’s another spectacle that should encourage you to turn your gaze skywards in August.
The Perseid meteor shower - often the best meteor display of the year - is a wonderful sight for all the family to enjoy.
Paul Fellows, chairman of Cambridge Astronomical Association - which is planning a star party and meteor watching event on Tuesday August 11 and Wednesday August 12 - gave us some advice on how to enjoy the show of what is often, erroneously, called shooting stars.
“These meteors start coming at the beginning of August, but peak on August 11 and 12 as the Earth passes through the debris left behind by comet Swift-Tuttle as it sweeps through the inner solar system on its 133-year orbit around the Sun,” he said.
“We won’t see the comet – the last approach was in 1992, so we have to wait over 100 years for the next one in 2126, when it will pass by the Earth at a distance of 14 million miles.”
Where to look to see the Perseids
“Position your chair so you’ve got a view of the largest chunk of sky possible avoiding any lights – north-east is good if you’ve a choice,” says Paul.
“If you haven’t got a garden or window facing roughly in that direction, or if you live in Cambridge or other places with lots of lights, just look straight up – there should be some meteors passing overhead.”
The predicted numbers of meteors vary wildly but it could be 50-60 per hour. It varies from year to year and tends to favour observers in the southern hemisphere.
While the pre-dawn hours can be the best time to see them, it is possible to see them for most of the night.
What causes the Perseids?
“The meteor shower is caused by the Earth crossing through the previous path taken by the comet, and the meteors are little fragments of comets that have been left behind by it, which the Earth sweeps up as the orbits intersect,” says Paul.
“Of course, this does reveal that one day we might find the whole comet at the cross over point when the Earth gets there - and there has been concern that it might collide with us on August 14, 2126.
“The orbits of comets is somewhat difficult to be exact about because of the effect that the solar wind from the Sun has on them, pushing them off course in unpredictable ways but observations of the 1992 pass helped astronomers, led by Brian Marsden at the Minor Planet Center, show that it was going to miss.
“His team have shown that we are safe for at least 2,000 years from this threat, but as the nucleus of Swift-Tuttle is a ball of rocky debris and ices packed together into a dirty snowball that is around 26km across, we will be keeping a close eye on it.”
Join in Cambridge Astronomical Association’s Virtual planet and meteor party
The Cambridge Astronomical Association is running a ‘Virtual planet and meteor party’,on August 11 and 12), which will be cast onto the web via Zoom live from Paul’s observatory.
It will feature talks about comets and meteors, and live imaging of the planets using a webcam plugged directly into Paul’s 14-inch telescope.
“We will be joined by other observing stations run by other members of the CAA and who will be targeting other objects, and we will be encouraging people to join in by watching for meteors and counting how many are seen and reporting them.
“The predicted numbers of meteors vary wildly but it could be 50-60 per hour. It varies from year to year and tends to favour observers in the southern hemisphere.
Details of the event are on the website caa-cya.org, along with the link to join us by Zoom – full details are in the panel, right.
Cambridge Astronomical Association’s star party and Perseid meteor watch will be held on Tuesday August 11 and Wednesday August 12 by Zoom. It’s free, open to all and there’s no need to book. Use password CAA. Visit caa-cya.org and click on CAA events, or go directly to the event page at https://bit.ly/2XvatYM.
- 8pm: Welcome and presentation of the plan for the evening
- 8.10pm: Talk ‘Shooting Stars and Space Rocks’
- 9pm: Q&A and chance to get refreshments
- 9.15pm: Observing Session 1 – The Giant Planets
- 10pm: Discussion session for a chat and chance to get refreshments
- 10.15pm Observing Session 2 – Perseid Meteor Watch
- 11.15pm Wrap-up session
All you will need is a garden chair, a blanket, a star chart from caa-cya.org/images/graphics/starmap.jpg, a pen and something to press on and a red torch. And, if you want to, get out your camera and tripod to image the meteors.
If you want to help the association collect data, you can just count the meteors or, if you wish, draw their paths on the print out of the star chart and jot down the time (nearest minute will do) beside the line you’ve drawn.
Adding some notes for each is helpful so if you wish you can add things like about brightness, colour, persistent train etc.
For those hoping to take some photographs, the exposure time will depend on light pollution and weather conditions.
Try the grand tour of planets in August
There is a parade of planets this month - and it’s possible to see every one in the solar system.
“They are lined up across the sky starting with Jupiter, followed closely by Saturn, both almost due south at midnight and in the constellation of Sagittarius,” says Paul.
“Next in line lies Neptune on the border between Aquarius and Pisces. Mars, in Pisces, rises just before midnight, but will make a fine sight if you stay up into the small hours.
“Next we have Uranus in Aries and then in the dawn twilight Venus rises at about 2.30am in Taurus and will be extremely bright. Lastly, Mercury is in Gemini and just peeps above the horizon at 4.30am an hour before the Sun comes up – so it is just possible to do the grand tour in one night at the moment.”