What’s Up in the Sky: Astronomy for February

By David L. Richards
Special to the Beacon Journal

Jupiter still reigns in the night sky, right between the Gemini twins, Castor and Pollux.

On Saturday around 6 a.m., you can see four planets and a dwarf planet stretching across the heavens. Look for Venus near the eastern horizon — the brightest she will be all year — and then moving west along the ecliptic, you will spot Saturn, Mars, Jupiter and dwarf planet Ceres on the western horizon. If you have access to a telescope, check out Venus — she appears as a crescent, and is at her greatest illuminated extent.

Mercury fades into the evening twilight over the first week of February, but later in the month reappears in the dawn, brightening as the month ends. Ceres lies within 10 degrees of Mars in the constellation Virgo. Between them lies Vesta, now the largest asteroid.

The accompanying chart shows you where to find these three celestial bodies. Or you can go to www.mckinleymuseum.org/hoover_price_planetarium and click on “Star chart for Mars, Ceres and Vesta in February, 2014.” The circle in the middle of the chart shows the field of a pair of 7 x 50 binoculars.

On Feb. 10, Jupiter and the waxing gibbous moon are only 5 degrees apart, and on the 25th, Saturn and the waning crescent moon are less than 2 degrees apart. In 2014, Saturn lies close to the path of the moon and in 10 months out of the 12, the moon occults the ringed planet. This month you have to be in Australia to see this phenomenon, but in late August we get our chance to see this absorbing event.

Uranus is low in the west in the constellation Pisces, setting mid-evening, and Neptune, near Mercury, disappears into the evening twilight early this month.

Q&A

Q: Does the light we see from a distant star reflect the star’s actual current position in the night sky? Or has the star “moved” due to the effects of precession and other motions, and the light we see is merely an artifact of its older position? For example, for a star 500 light years distant, are we seeing its position (coordinates) from 500 years ago?

— J.H., Hudson

A: Yes, that object has moved by the time we actually see it. Everything we see has moved from its position from the time light was emitted or reflected off it, until the moment we register it upon our retina.

Let’s start with an easy one. In the case of our moon, the light reflecting off the lunar surface takes about a second and a half to reach our eyes, so the moon has moved about 5,000 feet in its orbit about the Earth in that interval.

The calculation for the movement of stars would be similar (there are other vectors that must be included) but considering the tremendous distances involved, within a human lifetime the apparent distance would be barely noticeable. This is what is known as proper motion, and is generally measured in seconds of arc per year.

The star with the largest proper motion known is Barnard’s star, moving 10.3 arc seconds yearly. It would take 180 years for this star to change its position by one angular diameter of the moon.

Program

The Hoover-Price Planetarium is presenting The Universe at Large, our new program for 2014. Along with the current sky, we will be presenting and updating material to reflect new discoveries, astronomical events and NASA’s ventures. This format provides us with more flexibility to respond to questions.

The program will be shown at 1 p.m. Saturdays and 2 p.m. Sundays. The Hoover-Price Planetarium is located inside the McKinley Presidential Library & Museum in Canton. The planetarium is free with museum admission.

David L. Richards is director of the Hoover-Price Planetarium at the McKinley Presidential Library and Museum, 800 McKinley Monument Drive NW, Canton, OH 44708, www.mckinleymuseum.org. He can be reached at 330-455-7043 or email hooverpriceplanetarium@hotmail.com.


© 2014 The Akron Beacon Journal  ●  Ohio.com  ●  Enjoy  ● 44 E. Exchange Street, Akron, Ohio 44308