May 2014

Tony Martinez

                                   Tony Martinez

Each month I will describe sights of interest in the night skies of South Carolina. These sights will be broken down into three sections; what you can see with the naked eye, with binoculars, and with a small telescope. The best time to view the night sky is at and around the times when the Moon is not visible, what is known as a New Moon; which will occur this month on May 28th. For May, your best viewing nights will be from May 18th to the 31st. The Star chart below is set for Florence, SC on May 15th at 9 pm.

Sky Chart

A New Meteor Shower?

Each year there are three major meteor showers; the Perseids in August, the Leonids in November, and the Geminids in December.  Over the past several years, the Geminids have produced the greatest number of meteors. However, the amount of meteors seen in a given shower can change over the years.  In reality, there are meteor showers every month of the year, but most are not impressive.  Another significant factor in viewing any astronomy targets is having a dark sky viewing site. When observing meteor showers, the degree of darkness at your viewing site has a dramatic effect on the number of meteors you can see.

This month may bring us a new major meteor shower resulting from the Earth passing through the orbit of Comet 209P/LINEAR. This small comet, discovered ten years ago, comes in the vicinity of the Sun every five years, but is too small and dim to be seen. However, this will be the first recorded passage of the Earth through the comet’s debris field. This event may result in a good or even great meteor shower and it is worthwhile to check it out between 2 am and 5 am on a Saturday morning on May 24th; see location below.

Camelo

For the new readers, it is important to review the subject of meteor showers. Meteoroids are small pieces of rocky or metallic debris dispersed throughout the solar system. As the Earth revolves around the Sun, we run into these meteoroids, and as they enter the atmosphere, they become meteors, and the friction causes them to quickly burn up. We see them as a short streak of light, and they are usually referred to as “shooting stars.” This misnomer is a throwback to the distant past when ancient observers really had no idea what the stars were. In addition to the meteoric debris left over from the formation of the solar system, there is another more concentrated source of meteoroids; comets.

As a comet circles the Sun, gases and ice particles are released, along with the release of some of the comet’s rocks. These rocks become meteoroids, however, they do not disperse into solar system, but instead they remain in the orbit of the comet. So after several thousand years of circling the Sun, the entire orbital path of the comet is littered with meteoric debris. Since there are hundreds of known comet orbits circling the Sun, it is logical that our Earth would pass through some of these orbits at certain times of the year; see image.

comet-debris

When the Earth passes through one of these cometary orbits, we experience a large amount of meteors known as a meteor shower. On a normal night, one might see one or two meteors per hour, but during a meteor shower, one might see from twenty to one hundred meteors per hour or more.

Rules of meteor shower viewing: No binoculars, telescopes or any optical aids are needed, just use your eyes. Due to the position of the Earth and the stars during a particular entry into the meteoroid’s orbit, the meteors appear to becoming from a particular constellation, thus the name of the meteor shower. This new shower will appear to come from the region of the North Star. However, it is centered in the difficult to see constellation called Camelopardalis. If this does become an important meteor shower, it will probably be called the Camelopardalids.

Another aspect of watching meteor showers is viewing time. For most meteor showers, or for meteor viewing in general, the best viewing is after midnight. The reason is based on the positions of the Earth and you the viewer as the Earth runs into meteoroids. Before midnight, an observer would be on the side of the Earth opposite the direction of the Earth’s movement through space. From midnight onward, an observer would now be looking in the same direction that the Earth is moving through space. Therefore, we could easily see the meteoroids hit our atmosphere; a good analogy is like running through raindrops.  Remember, you will still see some meteors before midnight as the graze the upper atmosphere. The sketch below may help to better explain this concept.

meteors

So lie on the ground on a blanket, or use a chaise lounge chair to view the shower, using a standard chair may result in neck pain. Look in the direction of the North Star, but be aware of your peripheral vision since meteors may also appear in various parts of the sky. Don’t forget to bring snacks and drinks.

Saturn Returns:

If you have a telescope, small or large please take the time to observe the planet Saturn. It is now in the best ring view position since 2005.  Good Saturn viewing will continue from now throughout July. I will feature Saturn next month. Look for Saturn in the southeast above Scorpius as shown in the image below.

Saturn

Naked Eye Sights: Check out the possible new meteor shower on the morning of May 24th.

Binocular Sights (7 to 10 power): The summer constellations and summer Milky Way are returning, so scan the skies in the south to check out the beauty of the region near the center of our Milky Way galaxy.

Telescope Sights (60-100mm): The one major telescope target beginning this month, and continuing for the next few months; Saturn.

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