Constellation Leo can point you toward the southern galaxies

Saturday, Apr 14, 2018 5:05 AM

Greetings, Stargazers.

The constellation Leo is high in the southern sky. Leo can be found most easily by looking for the backward question mark, called the sickle, with the bright star Regulus as the dot underneath. If you are familiar with the pointer stars in the Big Dipper – the two stars at the end of the dipper that point toward Polaris – you can use these same two stars but go in the opposite direction to get to Leo.

At 10 p.m., Regulus will be due south 60 degrees above the horizon. Algieba, a little higher up in the sickle from Regulus, is a good double star for a small telescope. The two stars in the double are about one magnitude apart in brightness so can provide a pleasing view.

Last month, I said I would mention a few of my favorite southern galaxies in this month’s column, and Leo is a good place to start. A detailed star chart and a small telescope are essential for finding and correctly identifying these southern galaxies since none of them are visible to your naked eye.

There are two nice groupings of galaxies to look for in Leo. M95, M96 and M105 are set below the lion’s belly. They are all within 3 degrees of each other but may not be quite close enough together to be in the same telescopic field of view. Below the tail of Leo, M66, M65 and NGC 3628 make up the Leo Triplet, a much tighter grouping.

Following Leo in a large region to the east is the Virgo cluster of galaxies. A small telescope can make out scores of these galaxies, but unless you have a very detailed chart, or lots of practice, it is difficult to tell which is which. Even if you can’t tell them apart, it is fun to see things so distant. The elliptical galaxy M87 is the brightest and near the center of the cluster.

M64, the Black Eye galaxy in Coma Berenices, and M104, the Sombrero galaxy to the south of Virgo, both make excellent targets for small telescopes since they are relatively bright and have distinguishing dark dust lanes.

This month

Besides tax day, April also includes National Astronomy Day on April 21. (There is another astronomy day in October.) Starting Sunday and running through the 21st is International Dark Sky Week. The International Dark-Sky Association works to protect the night skies for present and future generations.

We are fortunate to live in one of the places in the country with really dark skies, and we should all make the effort to protect them. We can do this by making good decisions about outdoor lighting, especially turning lights off when possible and minimizing glare and eliminating light trespass when lights are necessary.

This summer should be great for planet watching and now is a good time to start. Venus is the evening star. Seen in the west at sunset, it is setting a bit after 9 p.m. At magnitude -3.9, it is the brightest thing in the sky after the sun and the moon.

A few minutes after Venus sets in the west, Jupiter will rise in the east. At magnitude -2.4, Jupiter is the next brightest thing in the night sky after Venus.

The summer Milky Way is rising just after 1 a.m. That is followed soon afterward by the planets Saturn and Mars, which will reach their highest point in the southern sky near sunrise.

By the end of the month, Mercury can be seen in the eastern sky right before sunrise. It will appear farthest from the sun on April 29.

The Lyrid meteor shower peaks on the evening of April 22. The moon will be setting around midnight, so the best viewing of meteors will be after that. Meteors that are part of this shower appear to radiate from the constellation Lyra even though they will be seen in all parts of the sky.

Charles Hakes teaches in the Physics and Engineering Department at Fort Lewis College and is the director of the Fort Lewis Observatory. Reach him at hakes_c@fortlewis.edu.