It's been a while since I wrote one of these, eh? Look, it's winter here, which is less conducive to getting outside and stargazing, and, notably, this winter has been pretty cloudy for me, so that really puts a damper on things too.
But, winter is also when some of my favourite backyard sky sights are visible, so let's get down to business!
I'm going to try to keep these short so that I can get through a bunch of related objects fairly easily, but I do tend to be long-winded, so we'll see how that works out.
Let's start with Orion!
If you're in the Northern Hemisphere and only know one constellation, it's probably the Big Dipper1. If you only know two, the second one is quite likely Orion. It's big, it's bright, it's easy to find, and it actually kinda sorta looks like something. I think it's actually easier to find than the Big Dipper, but it's not visible year-round like the Big Dipper is.
This time of year, look south in the early evening. The main thing you're looking for is three bright, evenly-spaced stars making a short line in the sky -- short enough that you can easily cover the whole thing with a fist held at arm's length. This is known as the Belt of Orion. The constellation Orion is said to represent a hunter wearing a belt, and this belt is one of the most recognizable arrangements of stars in the sky. The stars are bright (between magnitude 2.1 and 1.6) and visible even in light-polluted skies. If they're up, and you can see stars in the sky, you should be able to find them.
Once you've found them, look "up" and "down"2 from the Belt, and you should be able to spot four other stars in a rectangular formation around them. The constellation is big; if you think of length of the Belt as one unit of distance, the stars you're looking for are about two units from the ends of the belt. Two of these stars (the top-left and bottom-right) are very bright, and the other two are noticeably dimmer, but you should still be able to spot them. The two stars on top, the Belt in the middle, and the two stars on the bottom all form a sort of lopsided hourglass shape, and this is what most people think of when they say they've found Orion.
Orion represents a hunter. The top stars are his shoulders, the Belt is, well, his belt, and the bottom stars are his knees or feet. It does at least look kind of like a person in an abstract sort of way...
There is so much to say about Orion, but I'm going to limit myself to two quick facts.
FIRST FACT: The top-left star is called Betelgeuse, and I've learned its pronunciation as BAY-tull-gice (rhyming with "ice"), but many people pronounce it Beetlejuice, which is honestly much more fun. It's a SUPER INTERESTING star. It gets brighter and dimmer, noticeably so! In 2019-2020 it got super dim for a while and nobody was really sure why! One day "soon" it's going to EXPLODE (we think) and when it does, it will be brighter than the full moon and visible in the daytime. How soon is soon? Well, Wikipedia says "within the next 100,000 years", so don't hold your breath, but a while ago I saw a study suggesting it's likely within the next couple centuries or so. And if it went boom tomorrow we wouldn't be too astonished...when it got dim a few years ago there were a lot of astronomers kind of crossing their fingers and hoping that was a precursor.
FIRST-AND-A-HALF FACT: I may as well mention that the other bright star in Orion -- the one in the bottom right -- is Rigel (RYE-gull or RYE-jull). I have nothing interesting to say about Rigel, but it and Betelgeuse are the two well-known named stars in Orion, so now you know that.
SECOND FACT: Below the Belt of Orion is a short, dim vertical line made up of three-ish stars, seen as representing Orion's sword hanging off his belt. The middle of the three stars is actually a nebula, called Messier 42 (aka M42), or, appropriately, the Orion Nebula. With good eyes and a good dark sky you might see that it's a bit less well-defined than a typical star, and through binoculars you can start to see a quite beautiful nebula. The entire region is filled with stars; through my binoculars the three stars each split into doubles, making six, plus the nebula itself, plus a bunch of other stars hanging about the general area. If you've got binoculars, take a look! It's pretty!
Ok that's Orion! It's a huge signpost that we can use to find a bunch of other interesting things. If I remember to continue this series, we will use it to find:
- Sirius
- Procyon
- Castor and Pollux / Gemini
- Capella / Auriga
- Aldeberan / Taurus / The Hyades
- The Pleiades
Not in that order, though. The Pleiades is quite possibly my favourite thing in the entire sky so it's got a good chance at being one of the next two posts...
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Not technically a constellation. I don't care
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It's more precise to say "north" and "south", since Orion, like all constellations, changes orientation in the sky depending on your location, the time of night, the time of year, etc., so up/down aren’t always correct but north/south are. But if you're seeing Orion above the southern horizon, and the belt is vaguely horizontal (i.e. parallel to the horizon), then the constellation is "right-side up" from your perspective, "down" is south (down towards the southern horizon), and "up" is north (up through the zenith directly overhead and eventually to the North Star). Orion is annoyingly symmetrical so if you see it sideways it's not immediately obvious which end is “up”, but I still find it pretty easy to recognize the "top" and "bottom" even when I see it in an unusual location. If you know where the north star is, the top of Orion is always in that direction, which is why I should have just said "north". But I find it confusing to talk about the north side of something that's in the south part of the sky.
