The correct name for the meteor shower is Eta Aquarids. The name is given by the constellation in which the radiant of the stream is located – the place from where, from the point of view of an earthly observer, “shooting stars” – meteors – fly apart like a fan. Aquarius is the Latin name for the constellation Aquarius. The brightest star closest to the radiant is Eta Aquarius (η Aquarii) – it is also present in the name of the meteor shower.
And of course, this is a meteor shower, not a meteor shower. After all, we see barely noticeable sparks from microparticles burning in the atmosphere that met with the Earth’s atmosphere at cosmic speeds. Meteorites do not fall. Usually.
A meteor shower would be fatal for us. A meteor is just a beautiful sight.
The May Aquarids are generated by Halley’s comet – one of the most famous comets, but now – alas – dying. When she, with her tail shining in the night, instilled fear in the illiterate and religious representatives of mankind. Comet scientists have never been afraid. They studied them, followed them through telescopes from night to night, but they also did not immediately understand their nature.
More or less clear ideas about the nature of comets appeared in science about two and a half centuries ago, when Edmund Halley’s assumption was confirmed that comets revolve around the Sun in very elongated – elliptical – orbits, and regularly approach the Sun, and it is during periods of approach become visible. And Halley’s Comet became the first of the comets for which it was possible to accurately calculate the orbit.
Edmund Halley – English astronomer, physicist, geophysicist, mathematician, meteorologist.
But with each approach, the comet loses a significant part of its substance. In fact, this is a snowball, in which dust particles and small pebbles are interspersed. The snow melts, dust particles and pebbles are released, but continue to fly along the comet’s orbit. Most comets are accompanied by a swarm of meteor particles, which burn up when they enter the Earth’s atmosphere, because the speed of collision with the air shield of our planet is huge – the particles heat up to thousands of degrees and evaporate for a fraction of a second. The largest ones last a few seconds. And then there is a passage of a very bright meteor – a fireball.
The Earth twice a year approaches the orbit of Halley’s comet – not with the comet itself, but with its trajectory, along which microparticles once separated from the comet’s nucleus are rushing in a wide trail in space. During periods of such encounters, our planet utilizes part of this cometary substance. It will not be superfluous to know that due to this alone, our planet gains 40 thousand tons of “excess weight” per year – more than 100 tons daily.
One encounter with a meteor swarm rushing along the orbit of Halley’s comet occurs in October – the radiant of the stream is located in the northern part of the constellation of Orion, and therefore is called the Orionids. This is a fairly noticeable and convenient meteor shower for observations in the northern hemisphere.
The second rapprochement of the Earth with the orbit of Halley’s comet occurs in April-May – the same “May Aquarids” or – Eta Aquarids – in a scientific way.
Geographic preferences aside, the Eta Aquarids are a very active stream. And the maximum you can count up to a hundred meteors per hour – 3 meteors every two minutes. It looked like a real meteor shower. But there are a few caveats.
The so-called “zenith hourly number” – the number of meteors flying in the zenith region, limited by a sector of 60 degrees – is a generalized value calculated on the basis of aggregate data from several experienced observers, each of which can notice only a part of the meteors, for example, half of their total numbers.
Such measurements make sense for situations where the radiant of the meteor shower – that region of the sky from which meteors and fireballs fly – is also located in the near-zenith region – high enough above the horizon.
And, of course, it makes sense to observe meteors away from cities where street lighting has not known any measure in recent years – everything is lit up with poisonous orange lights, the light of which is very strongly scattered in the atmosphere and sometimes even makes it impossible to see bright stars.
And there is also such a thing as “observability coefficient”. Not a single observer sees all the meteors flying by during his participation in observations – he sees only a part. even a group of several observers does not see the total number of passing meteors, from which the zenith hourly number is determined.
Let’s put it all together. Or – subtract, which is probably closer to the point.
It makes sense to observe meteors if:
- the night is clear, the atmosphere is transparent;
- you are away from the city;
- the radiant rises high above the horizon at night;
- Do you have observational experience?
- there are a lot of you.
The last two points are a matter of gain and an organizational issue. But the first three – alas – do not depend on us. And what do we have for them?
The weather in May can be good – that’s a plus.
It can be difficult to hide from the city – as soon as you drive away from one city, you immediately enter another. Even small settlements are now illuminated like airfields – light sources have become economical – electricity is not a pity. Therefore, it is necessary to go to the mountains. But is it worth embarking on a trip for the sake of the Eta Aquarids?
Specifically, no. But if you were planning to go to the mountains for the May holidays, then it makes sense to see the stream there. Fortunately, the mountains – in the Russian geographical representation – are located in the south … most likely. And here we come to the most important point:
In the northern latitudes in early May (and the maximum activity of the Eta Aquarids occurs in the first days of May – on the night of 4 to 5 or 5 to 6 May), Aquarius hardly manages to rise above the horizon before dawn. And this is the main disadvantage that crosses out everything else. Not only do white nights come to the middle northern latitudes in the first decade – the sky no longer becomes completely black (even if all city lights were suddenly turned off), and the evening twilight begins to merge with the morning. Plus, the stream’s radiant only rises to 10 degrees above the horizon by dawn. That is, there can be no question of any near-zenith location of the radiant. And the radiants located near the horizon do not give meteors. Alas, no matter what the media writes about meteor or even “meteorite” (which is a mistake) rain on the upcoming night – from May 4 to 5, there will be nothing like this in central Russia.
At what latitudes does it make sense to observe the Eta Aquarids meteor shower?
Observations are not hopeless from the 45th parallel north and south, and it would be ideal to observe at the equator and in the southern hemisphere. In the southern hemisphere of our planet, the Eta Aquarids are indeed an interesting stream to observe, comparable to the August Perseids, which many astronomers are well aware of. In absolute terms, the activities of the Eta Aquarids and the Perseids are very similar. But the Perseids are perfectly visible in the northern hemisphere – this is our most important meteor shower, and completely invisible in the southern – for the same reason – the Perseids remain under the horizon there or barely peek out from under it. Eta Aquarids is one of the main meteor showers for astronomy lovers in Australia, Argentina, Chile, Brazil, Peru. But in the northern hemisphere, this stream is practically unobservable, especially in its middle latitudes.
It is interesting that even the media close to science and science-oriented sites continue to misinform astronomy lovers about the Eta Aquarids stream, promising dozens, if not hundreds of shooting stars per hour.
I have made many observations of meteors with groups of observers of varying skill levels. And even when observing a very active Perseid stream – in the best conditions – on a moonless night, in places with minimal or no urban illumination – there were always people who could see only one “shooting star” per hour. This is despite the fact that the hourly zenith number for the Perseid stream is estimated at 100 meteors per hour.
Expectation: 100 meteors per hour
Reality: 1 meteor (or even none).
And this is for the most convenient and active flow!
Eta Aquarids are completely inconvenient for the inhabitants of the northern hemisphere, and are 2 times less active than the same Perseids.
Draw your own conclusions.
I would like to end this explanation positively. And if someone asks:
“So, why don’t you go out under the stars next night?”
I will answer:
What’s the point?
Stars and astronomical observations are always beautiful, even when there are no active meteor showers.
Plus, “shooting stars” – meteors – do not always have to do with a certain stream. And the Earth on its way regularly meets with lonely dust particles or pebbles – they did not fall off the comet, they are on their own. These are the so-called out-of-stream or sporadic meteors. And every night they fly into our atmosphere. The main thing is to notice. And there is a chance to notice them any night if there is no moon in the sky.
There will be no moon in the sky tonight.
And if the weather is favorable for observations, go under the stars and just contemplate them with a wandering eye. This is exactly how meteors should be observed – not focusing on some bright star or some constellation, but simply walking around the sky with your eyes. And then, maybe you will see your shooting star and have time to make a wish.
PS: If, after my story, someone remains optimistic and still wants to find that place in the sky, from where several meteors related to the Eta Aquarids can fly out next night, I will tell you how to find this place. And when to look for it.
The constellation Aquarius begins to rise (in early May in the middle latitudes of the northern hemisphere of the Earth) shortly after midnight. But Aquarius – the constellation of the south – its path above the horizon canopy. It rises slowly, as if reluctantly. And by three o’clock in the morning, when the sky is already brightening, only half of the constellation will appear above the horizon. The radiant will be at an altitude of about 5 degrees. However, in the inevitably brightening sky, Aquarius will still be visible for about half an hour, or even 40 minutes. Who knows? – suddenly you are lucky, and you will see a shooting star from the meteor shower of Eta Aquarids, although this is unlikely.
There are at least two ways to find the radiant of a shower.
Method one: From the summer-autumn triangle.
If you have read my article about the constellation Dolphin (or listened to a lecture), you can do the same trick that was suggested for finding the constellation Dolphin in the sky.
Three bright stars – Vega, Deneb and Altair form the famous asterism – the Summer-Autumn Triangle. And although the best time for its observation is summer and autumn, in May it is already well seen. In the early morning hours of May, the two brightest stars of this triangle rise quite high – almost to the zenith. This will help you find them. If you connect the brightest of the stars of the summer-autumn triangle – Vega – to the middle of the triangle, and extend this line further – to the horizon, you will first stumble upon the small and beautiful constellation Dolphin. Extending this line further – to the horizon (down) for the same distance, you will find yourself in the region of the radiant of the Eta Aquarids meteor shower. it makes no sense to look for it especially precisely, because it is in it that meteors are not visible, but they scatter in all directions from this location.
Method two: Under the neck of Pegasus.
Find the Big Dipper bucket in the northwest. In May, in the pre-dawn hour, it is there – not high above the horizon. Connect the two extreme stars of the bucket and find the North Star in this classic way. Move on in the same direction twice as far as you flew from the Bucket to Polyarnaya. You will come across Pegasus Square. The square is not the whole constellation of Pegasus. Just like the Bucket is not the whole Bear. Pegasus also has a neck and a head (and much more, which is not so important now). If you face east (the sky has already brightened there, or the North Star will help you find the direction to the North, and then all the other sides of the horizon), then the Pegasus square will rise with its peaks up, down, left and right. A chain of stars stretches from the right peak – the neck of Pegasus. Exactly under the neck begins the constellation of Aquarius and right there is the radiant of the stream of Eta Aquarids.
Good luck with your observations!
Musical appendix to the article
And some music on the topic of the article:
Music album “Fallen Star Story»: