There’s a Greater and Lesser Dog in the sky, so in the interests of fairness there has to be a pair of cats as well. But these are no ordinary moggies, knocking over the heavenly dustbins – they are nothing less than lions. Leo is the main lion, and above him is a rather insignificant Lesser Lion, Leo Minor.
Leo himself is crouching down, mane held high, gazing across the Crab, Cancer, towards Gemini, the Twins. If you have ever thought that the constellations were just the result of over-active imaginations, and look nothing like what they are meant to be, Leo will put you right, because it really does look like a lion, at least as much as you can expect stars to be. It’s not surprising that this group of stars was seen as a lion by many peoples, and is one of the most ancient constellations of all. Perhaps even our very distant ancestors recognised it as a lion – when they weren’t trying to avoid being a real lion’s next lunch.
The brightest star in Leo is Regulus – Latin for ‘little king’, because this was a regal star in ancient times, and of course the lion is the king of beasts. Regulus is at the south end of a backwards-question-mark shape, known in more agricultural times as ‘The Sickle’. At the other end of the lion figure is Denebola, from the Arabic for ‘Lion’s tail’. The word Deneb crops up elsewhere in star names where it marks the tail of a creature.
Sextans, the Sextant, is really only there because people decided to fill in the empty gaps between the main constellations, so there are no bright stars there. It commemorates the the navigational device that was so useful to voyagers in the 18th century.
For hints on understanding the star map, please click here
Things to look for in Leo
Unlike some other constellations, Leo doesn’t have any easy-to-see objects in it that you can spot straight away – no star clusters or nebulae, for example. Instead, you’ll have to look more carefully. Binoculars will help, particularly if they magnify 10 times or more, but a telescope is better. The green ovals on the map above show the positions of some groups of galaxies that are visible in average skies with a small telescope, though you’ll have trouble finding them with a small telescope if there’s a lot of light pollution around. There are no labels on the map above, to avoid cluttering it, but the left-hand hand group are the brighter ones and include M65, M66 and NGC 3628, while the right-hand group are M95, M96 and M105. The map below shows the area in more detail.
Start off by trying to find the M65-66 group. There’s a convenient pattern of stars nearby which you can see in binoculars or a telescope finder, and they also lie roughly midway between two brighter stars which you might be able to get on opposite sides of the field of view of your binoculars. The photo at right shows the sort of thing you’re looking for – slightly elongated small fuzzy blobs. And above these, just visible, is the edge-on spiral galaxy NGC 3628.
Having found these, now look some distance to the west to find the somewhat fainter M95, M96 and M105 group. If you get to Regulus, you’ve gone way too far.
If you got these galaxies, you should be able to spot NGC 3115 in Sextans, shown on the main map a long way south of Regulus. It’s about as bright as M65 and M66, but not as easy to find because there are fewer stars in the area. You’ll have to find the two fifth-magnitude stars on either side first. It’s a spindle-shaped galaxy, of a type called a lenticular galaxy, meaning lens-shaped.
While you’ve got your telescope out, take a look at the star Algieba. It’s a double star, though you’ll need a magnification of about 200 to see the two stars well. They are both a lovely golden colour, which shows up well in a telescope.
Text by Robin Scagell