This week (May 10-16, 2010) and the coming weekend is an excellent time to go outside and find the ecliptic in the sky. You don’t need a telescope or even a pair of binoculars. A lot of backyard astronomy can be done by just taking a few minutes and going outside and looking.

The ecliptic is defined as the path of the Sun against the background stars, or the plane generated by Earth’s orbit. However, both of these statements are not very visually helpful. It’s difficult to see any background stars when the Sun is up, and it’s tough to find Earth’s orbit when we’re on it. However, the ecliptic is also described as the plane, or ‘flatness,’ of the solar system. All the major planets orbit the Sun relatively close to the ecliptic plane. There are also several bright stars that lie very close to the ecliptic. This week, we have three planets, the Moon and three bright stars that can help us see the ecliptic plane across the night sky.

When viewed at 10 pm, MDT on Friday, May 14, 2010:
Venus is low on the west-northwest horizon at a bright magnitude -4. Venus sets just after 11 pm.
Mars is high in the southwest at 45 degrees above the horizon. It has a reddish appearance and is a descent magnitude +1.
Regulus, the bright blue star in Leo, is just over 10 degrees east of Mars. Regulus is often referred to as an ecliptic star, because it is so close to the ecliptic.
Saturn is due south at 10 pm, 50 degrees above the horizon, at magnitude +1.
Spica, the bright blue star of Virgo, is also close to the ecliptic and is 34 degrees above the south-southeast horizon at the date/time specificed.

If that’s not enough, as Venus sets Antares, the red heart of Scorpius, rises in the southeast. Antares is a +1 magnitude star 5 degrees south of the ecliptic.
But wait, that’s not all. A young crescent Moon appears near Venus on the evenings of the 15th and 16th, also on the ecliptic plane.

I suggest that you do this more than one evening, just to make sure you know what you’re looking at. Once you recognize the ecliptic, watch the waxing Moon for several days, preferably at the same time each evening, and you’ll see it march eastward along the ecliptic.

(images generated with Starry Night Pro, v6.3.9)

Clark Planetarium,University of Utah and Salt Lake Astronomical Society are partnering this year to provide a full day of family-friendly activities, many of which are free.

Join us on Saturday, April 24, 2010 for opportunities to look at the sun and stars through telescopes, participate in science demonstrations and see presentations in Clark Planetarium’s Hansen Dome Theatre for just $1 each.

Clark Planetarium will also be giving away a  Celestron 50th Anniversary FirstScope telescope courtesy of Celestron Telescopes.

A complete schedule of events is available on online and discounted theatre tickets will be available for purchase at the ticket window the day of the event.

This family-friendly event will provide audiences the opportunity to learn first hand about the experiences of an astronaut who has also been a long standing member in the Salt Lake community.  ”Jake Garn is a tireless and tremendously effective advocate for space science education,” explains Clark Planetarium director, Seth Jarvis. “Jake has been a invaluable member of our Board of Directors since we opened seven years ago and his perspective on the U.S. space program and its role in our society are both thought provoking and definitely worth paying attention to.”

After Senator Garn’s presentation, audiences will take a three dimensional journey into the far reaches of the universe through the newly released IMAX film, Hubble 3D. Narrated by three-time Academy Award nominee, Leonardo DiCaprio, the film explores the significance of the Hubble Space Telescope and how the instrument has better helped us to understand the universe and the extraordinary work performed by shuttle astronauts to maintain and improve the telescope.

The event will take place Tuesday, April 13, 2010 from 7 – 8:30 p.m. in the ATK IMAX Theatre. Tickets are available for $8 for adults, $6 for children under 12, or free for Clark Planetarium members. Tickets can be purchased on the planetarium’s website or at the ticket window.