August 2015

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 August 14th. For August, your best viewing nights will be from August 7th to the 18th. The Star chart below is set for Florence, SC on August 15th at 9 pm.

wholeskychart1

Pluto:
As of last month, Pluto was still seen only as a fuzzy ball. On July 14th the New Horizons spacecraft successfully flew by Pluto taking the first close up images of Pluto, along with thousands of bits of data collection. During the last few weeks of July, NASA had several news conferences to show and discuss the preliminary photo and data collection. The one feature that was most prominent was the now famous Pluto “Heart.” The below images were taken before the fly by, and show both sides of Pluto along with its moon Charon; the fly by was on the heart side of Pluto.

01

 

Below is the, to date, best overall view of Pluto.

2b

 

Along with the best view, to date, of Pluto’s Moon Charon.

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And finally some of the many close up views of Pluto’s surface.

10Perseids Meteor Shower:
The Perseids meteor shower is a favorite for many observers because it occurs during the warmth of summer, and you don’t have to worry about getting up early for school the next day. The shower should peak on the night of August 12th and early on the morning of August 13th. The Perseids shower always has the potential of a good display, but for several years only a few meteors have been seen. This year the shower occurs during a new Moon, and astronomers predict a great meteor shower with as much as 100 meteors per hour! Please don’t be upset if you only see a few meteors, meteor shower rates are difficult to predict.

For 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. So on any given night of the year it is likely that you will see a few meteors streak through the sky. In addition to the meteoric debris left over from the formation of the solar system, there is another more concentrated source of meteoroids; comets.

Comets are balls of ice, gases and rocks that circle the Sun in elliptical orbits, and these orbits are usually above or below the plane of the planets in the solar system. 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 the 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.

When the Earth passes through one of these cometary orbits, we experience a large amount of meteors known as a meteor shower. See below:

periodic_shower

 

On a normal night, you 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 be coming from a particular constellation, thus the name of the meteor shower. Therefore, the Perseids meteor shower is centered on the constellation of Perseus, which rises about midnight in the northeast on August 12th. See below:

Perseids

This brings us to another aspect of watching meteor showers; time. For most meteor showers, or for meteor viewing in general, the best viewing is after midnight. This is based on the positions of the Earth and you the viewer as the Earth runs into the 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 easily see the meteoroids hitting our atmosphere; a good analogy is like running through raindrops. Remember, you may see some meteors before midnight as they graze the upper atmosphere.

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 Perseus (northeast), but be aware of your peripheral vision since meteors may also appear overhead or toward the north or south.

Naked Eye Sights: Perseid’s meteor shower

Binocular Sights (7 to 10 power): The area in and around the Summer Milky Way in the south.

Telescope Sights (60-100mm): Saturn remains a good target in the southeast. Search out Messier Objects in Sagittarius, Scorpius, and along the Milky Way

 

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