Caoimhín's Content

We’re back with another monthly overview! Before we get into this month proper, we did just have a partial Lunar Eclipse which you can read a bit about in previous posts, we also just passed the Opposition of Jupiter. We have discussed oppositions and especially Jupiter in previous videos and posts as well. Jupiter is a very prominent feature of the sky at the moment, and along with Saturn in the early evening and Venus in the morning, those planets have been visible for a while and will continue to be; they won’t be our main focus here.

Of course, after a whole video about the motions of the planets, I do point out the Venus appears to be moving backwards, the (apparent) retrograde motion of Venus. Over the course of a few days, the stars will all appear to move one way, while Venus appears to go the wrong way. Venus is just continuing its normal orbit around the Sun, but from where we’re standing it seems to be going backwards, again there’s plenty about this in a previous video.

Instead, just above Venus in the sky we have Leo the Lion, a quite famous and reasonably recognizable constellation. Leo gives its name to the Leonid meteor shower, a meteor shower that we will see on the 17th and 18th of November, so coming up very soon after this gets posted.

Meteors are just little bits of dust and rock that burn up in our atmosphere. We may call them shooting stars, but luckily they are much much smaller than the real stars. Even a meteor the size of a tennis ball can do some damage, and most of the shooting stars we see are smaller even than that. There’s always a few coming through the sky, but on some nights we get more, sometimes way more.

As the Earth orbits the Sun, we move through trails of dust and gas left behind by comets. This trails create a little patch of space with more dust and more potential meteors. It is when we pass through these trails that we get a meteor shower, a spike in the amount of meteors we get to see. Normally, we get about 10 meteors an hour passing right across the middle of the sky, the zenith right above you. This rate is known as the Zenith Hourly Rate or ZHR. 10 isn’t that many, especially when some are quite faint and a few will be behind clouds or blocked by light pollution. When we move through a cloud of dust, this rate increases, sometimes into the thousands.

An exceptional Leonid shower can produce thousands and thousands of meteors, but this isn’t always the case. You may see loads of shooting stars, or just a few more than a normal night. How can we tell that the meteors we see are Leonids? Because they all seem to come from Leo, they radiate out from the constellation Leo. If you were to spot a meteor and trace it back, following its tail backwards across the sky, it should pass through Leo if it is a Leonid. By tracking many meteors and finding where there paths cross we can find this originating point, the radiant of the meteor shower.

In the linked video we get to see what an exceptional rate would look like, but even a much lower Leonid rate will still add to the background rate, giving us a better chance of seeing something, even better if you are in a dark clear sky.

Leo won’t rise into the sky till close to morning time, but the meteors will be visible at any time of the night. The famous figure of Orion the Hunter is finally coming up at a more reasonable time of the night, from as early as 10 o’clock the constellation will be visible, by around midnight it will be due south in the middle of the sky.

For the previous months, the Summer Triangle has been close to due south at sunset, but now as we push into winter it appears already a little further to the west, closer to the setting Sun. Instead we have Pegasus the Flying Horse right in front of us as the sky darkens. You can recognize the constellation of Pegasus by looking for the square of Pegasus, a square shaped asterism. Again, if you’d like to learn the difference between a constellation and an asterism, you can take a look back at previous posts.

The constellation of Pegasus flows into the constellation of Andromeda, close the constellation of Cassiopeia and Perseus. Perseus is a fin shaped constellation, almost like a shark fin sticking clear of the water. Many of these characters feature in the same Ancient Greek myth, but we’re mainly looking for their shapes here. A nice recognizable shape up at this time of the year is Auriga, a pentagon shaped group of stars representing a Goatherd, like a shepherd but for goats. We’ll talk more about those constellations in the future.

For now, we are moving on to Uranus. Uranus is just coming into opposition this month, directly behind the Earth, in a straight line with us and the Sun. Just like a Full Moon, this is when the planets are at their brightest, as well as being at their closest to the Earth. Even in this perfect position, Uranus is just a little bit too far away to see with the naked eye, even under a dark sky free from light pollution.

Luckily, you don’t have to spot Uranus with your eyes, it’s right between the Pleiades and Jupiter. The Pleiades or the Seven Sisters are a group of bright young stars, mentioned in our past video about Deep Sky Objects. Both the Pleiades and Jupiter are nice and visible, Uranus is right in between them. A telescope should help you spot that it doesn’t twinkle and has a teal-y pale blue-ish green color. We take a brief close-up to show the color, as well as the very faint rings and the names of some of its moons. You may recognize the names as being characters from Shakespeare, Juliet from “Romeo and Juliet”, Puck from “A Midsummer Night’s Dream”. We will take a deeper look at Uranus in the future, but it is worth mentioning that Ariel and Umbriel are names from a work by Alexander Pope, not Shakespeare, even though Umbriel is also the name of a Shakespearian character. Uranus was also nearly called “George”, so we’ll have lots to talk about regarding names.

That’s it for the introduction to November, of course we will come back to meteor showers and Uranus, just as we will come back to eclipses and the rest of the planets. Space is big, so there is plenty to talk about, and I hope you will join me here next time to talk about them.