learn the constellations

In this part of the year, one of the easiest constellations to spot is Aquila. “Aquila” is the Latin for “eagle”, and it really reminds me an eagle. The brightest star is Altair, and it looks like the eye of the eagle. There are two stars apparently near it, Alshain (the tip of the beak) and Tarazed (the top of the head). Then, there are some stars that gives the constellation the shape of the spread wings.

It is quite surprising that, despite the Milky Way crosses this constellation, it contains no relevant nebulae or star clusters (it contains many, actually, but none of them easily visible with binoculars, for example).

Altair is one of the three stars that compose the Summer Triangle asterism (being the other two stars Deneb, in Cygnus, and Vega, in Lyra).

From Aquila other constellations are easier to find, such as Capricornus, Scutum, Serpens or Ophiucus.

Since I started to work seriously on this goal, I am enjoying much more the night sky. I am missing the stars when it is cloudy. I am speaking a lot more to other people interested in astronomy, getting into interesting conversations. I recognise much better the changes in the sky (such as travelling planets, or the constellations according to the season).

In short, I am really starting to feel myself a more complete person, closer to what I want to be.

I am not finished yet, but I would say I am over half way. I am not just learning the constellations, but I am also focusing on the important stars and Messier objects, making sure I learn something more than just names.

One of the nicest constellations that can be seen on these late summer days is Virgo. It is well known that you can find it if you «follow the arc [of the Big Dipper] to Arcturus and speed on to Spica [so, if you just continue the arc you will find Spica]». This is especially useful, as Spica is the brightest star in Virgo.

Virgo has other interesting stars, such as Porrima or Vindemiatrix, but they are not even close to Spica’s brightness.

Another interesting thing about Virgo is the fact it is home to the spectacular Virgo cluster of galaxies. If a cluster of stars is wonderful, and a galaxy is majestic, just imagine how can be a cluster of galaxies! It is 65 million light-years away… and even so, all those galaxies are in the same supercluster we inhabit (which, by the way, is the Virgo Supercluster, not to be confused with the abovementioned Virgo cluster of galaxies).

Also, you must remember that Virgo is home to 3C 273, which, despite its name (which might suggest more something like a zip code), is a quasar. In fact, it is notorious for at least two reasons: it is the first quasar discovered, and it is the brightest one (at least from this part of the universe). The photo in this entry is of this quasar.

However, if you just count with your naked eyes, you will have to imagine all these things, as 3C 273 has an apparent magnitude of 12.9 and the brightest galaxy in the Virgo cluster is M49, which has a 9.4 magnitude (a norml human can se up to the 6th magnitude).

However, you are lucky, as these days you have both Saturn and Mars in this constellation. Enjoy!

Canis Minor is a small constellation you can find up and left from Orion. It is not far from Canis Major, and both constellations have a very bright star each. I would say Canis Minor and Canis Major had been set in ancient times just to give home to Procyon and Sirius respectively.

Procyon is a small star that appears to be big because it is very close to us (11 light years) in comparison to other stars. However, it is bigger than our Sun. It is “married” to Procyon B, which is a white dwarf. This companion is probably preventing Procyon from being home to living beings, because it makes impossible having planets with stable orbits within Procyon’s habitable zone.

The other easy to spot star in Canis Minoris is Gomeisa.

What could I say about Orion? It is one of the most impressive constellations in the sky (especially the winter sky for the Northern Hemisphere).

I don’t know if it is the belt, with its three equally bright stars in Indian file. Or perhaps it is Betelgeuse, the huge (but young), impressive reddish star that might explode within the next million years. Or Rigel, its blue counterpart on the other side of the belt. Perhaps it is the Orion Nebula, which can be seen with the naked eye… I don’t know, probably it is everything together that makes it fascinating.

Probably I am not the only one who is using this constellation as starting point to locate the other constellations. Orion is a treasure in the sky!

Today is Cassiopeia’s turn. It is easy to spot, because it is the big W (or M) you can see in the northern sky. If you live in the Northern Hemisphere, you will be able to see it all the year. But if you live in the Southern Hemisphere… you will never see it!

Cassiopeia has two open clusters, M52 and M103, but you will need binoculars to see them.

By the way, here you will find something funny that happened about today’s constellation.

You probably know well where the nearest chemist is (yes, that one down the street). If a tourist drops in asking where can he buy aspirins, you would let him know in five seconds. Fine… but, what if a space tourist drops in asking where the nearest star cluster is? Huh? You don’t know? Come on, you have been all your life long in this part of the galaxy and you need to check the wikipedia to answer? Yes, it is right there, the Hyades. You just take your spaceship up and then right. You can stop at Aldebaran if you want to have a break (it seems to be part of the Hyades from here, but actually it is half-way).

You could even take the sightseeing tour and visit the Pleiades, which is also quite near our Solar System (in fact, it is the third nearest star cluster, after Hyades and Coma).

Then, you have other gems in Taurus, apart from these impressive star clusters. For example, you have the remnants of a supernova that exploded almost one thousand years ago, having been spotted by everyone but Europeans (we were too busy about the schism between the Catholics and the Orthodoxes back then, and the the Englishmen were occupied invading Scotland).

Looks like Taurus has many interesting things to see around.

I always loved this constellation because it is home to a very interesting star: Algol. It is an eclipsing variable. This is not something quite peculiar, there are lots of variable stars. But the fact is that its variations can be seen very easily. Algol is bright enough to be observed from a big city, and its variations (whose cycle is of almost three days) is reasonable to see the difference in two consecutive nights (Algol varies because it is a binary star, and their orbiting plane is in our direction, so they eclipse each other).

Perseus has also two Messier objects, the Little Dumbbell Nebula, and the open cluster M34. Perhaps too dim to see them with the naked eye, but it is good to know.

I have to admit I have very recently learnt how to recognise Aries. In fact, for a city-dweller, Aries is a bit tough: it has only two stars brighter than magnitude 3 (Hamal and Sheratan). And, according to the first axiom of Euclid, two dots make a line. Nothing else! So, how can you tell in the sky one “line” from the other?

But there are a couple of things that help. For example, Taurus is quite easy to spot. If you trace a straight line from its brightest star (Aldebaran) and the Pleiades, you will find a faint constellation, Triangulum. Its stars are not very bright, but, since they make an isosceles triangle, you can recognise them. Then, you will easily find Aries under Triangulum.

After a bit of research, I have discovered some astronomers defined an unofficial constellation, Musca (the Fly). This constellation was made of three or four dim stars of Aries, half-way between the Pleiades and Triangulum. If you watch carefully you will be able to see even these tiny stars.

Today I have been watching Lepus. I like this constellation, as it is “home” to one of the first brown dwarves ever discovered, Gliese 229B (it is far too dim to be observable, however, but it is nice to know it is there).

Lepus is right under Orion, which makes it easy to spot, even though its stars are not really bright.