Astronomy for RVers – Orion the Hunter

Winter’s most recognizable constellation returns

By Chris Fellows, Serenity Mobile Observatory

As the temperatures drop and the nights get longer, a favorite constellation dominates the night sky. Orion is one of the pictures in the sky that most people can recognize and name almost to the level of the Big Dipper (Ursa Major). It’s big, nearly 30 degrees tall and 40 degrees wide, and its major stars are bright: Rigel is nearly magnitude zero – in other words, nearly the brightest star in the sky.

To find Orion at this time of year, go outside and look east almost any time after 8 p.m. and you won’t be able to miss it – its iconic shape just jumps out at you. The three “belt” stars, namely Alnitak, Alnilam, and Mintaka, are the stars everyone keys in on when finding Orion. But Betelgeuse (my favorite star in the sky) blazes bright orange amongst all the stars in the sky and will draw your eye as well.

Orion is a great constellation for small telescopes or even binoculars. The large and very bright star-forming region called Messier 42 or The Great Orion Nebula is a perfect target to help hone your pointing or aiming skills. Once you find Orion and identify the “belt” stars, look a little closer and under any but the worst light polluted skies you should see three more stars “hanging down” from the belt. The star closest to the belt is called Mizan Batil and the lowest or farthest from the belt is called Hatysa. The middle “star” isn’t a star at all. It is a huge molecular cloud of hydrogen and other gases that is actively forming newborn stars.

To find the nebula, point your instrument in the general direction of Orion. If you are using binoculars, locate the three belt stars discussed above. Center your view on Alnilam, the middle star in the belt, and then move slowly “down” or south until another bright star, Mizan Batil, is in your field of view – you’re getting close now. Continue south and when M 42 comes into your field of view you will know it. It is best to do this with a stabilized instrument, so your binoculars should be mounted on a tripod or at least set on something solid. If you are using a telescope, follow the same procedure but use your finder scope to get close and then make sure you have a low power (25-35 mm) eyepiece in your focuser. Once you have Orion centered, you can move up to a higher power if you want to.

Also in Orion is another fairly bright nebula call Messier 78, or Casper the Friendly Ghost Nebula. This is an interesting reflection nebula with dark lanes of dust silhouetted by a glowing and ghostly larger cloud of gas behind it. To find M78, start at Alnitak, the left-most star in the belt asterism. This time you will have to move north or “up” towards Betelgeuse. The nebula is located about 1/4 of the distance between Alnitak and Betelgeuse and a little to the east or left of the line between the two.

Use a tripod and take your time. You have to remember that these objects are much fainter than your eyes were evolved to see. Spend some time, at least 20 minutes, in the dark prior to looking for these objects. This will give your eyes time to get as dark adapted as possible. Put away the cell phone or you will ruin your ability to see faint objects. Take deep breaths prior to looking through the eyepiece. More oxygen means better night vision. You can also use a trick called averted vision to focus your rods, not your cones, on faint objects

There are several other interesting targets in Orion but I will let you discover them on your own. Let me know if you are able to find these targets next time you are out there. I love to hear from my readers about that moment when you find and observe one of these elusive and beautiful celestial objects.

Till next time!

Clear Skies,
Chris Fellows, Serenity Mobile Observatory

Find Chris on Facebook (or, if you’re lucky, at your campground). (Editor: Check out his amazing photos on his Facebook page!)