October 2011

Your guide to the stars

You can use the chart as a guide when looking at the night sky. The chart shows the sky as it will be at 10 p.m. on Oct. 1; 9 p.m. on Oct. 15; and 8 p.m. on Oct. 31.

Hold the chart so the direction you are facing is at the bottom. For example, if you are facing north, turn the chart around so the “N” representing north is at the bottom as you hold it out in front of you. The center of the chart represents the portion of the sky you see if you look straight up.

To keep your eyes adjusted to the darkness as you look a the night sky, use a red-light flashlight to view the chart. You can make your own by putting red cellophane over the light or by coloring the lens of the flashlight with a red marker pen.

Sun: Oct. 1 – Sunrise: 7:22 a.m.; Sunset: 7:14 p.m. / Oct. 15 – Sunrise: 7:32 a.m.; Sunset: 6:57 p.m. / Oct. 31 – Sunrise: 7:44 a.m.; Sunset: 6:40 p.m. (exact for Waco, Texas)

Moon: Oct. 3: 1st Quarter / Oct. 11: Full / Oct. 19: 3rd Quarter / Oct. 26: New

Night Sky Events

Held at arm’s length, the width of your fist is 10º and the width of your index finger is 1º . The width of a full Moon is ½º .
Oct. 3 Mon. evening: The Moon is at 1st quarter.

8 Sat. all night: The Draconid (Giacobinid) meteor shower peaks but the nearly full Moon will wash out all but the brightest meteors.

11 Tue.: The full Moon is called the Hunter’s Moon and the Dying Grass Moon.

19 Wed. morning: The Moon is at 3rd quarter.

21 Fri. morning: The Orionid meteor shower peaks tonight with the best views likely to come before the Moon rises in the wee hours of morning.

26 Wed.: The Moon is new.

27 Thu. early evening: A thin crescent Moon (bottom), Mercury, and Venus (top) are aligned vertically just above the western horizon after sunset.

28 Fri.: Jupiter is at opposition – opposite the Sun as seen from Earth – when it rises at sunset, is up all night, and sets at sunrise.

31 Mon.: Halloween, a cross-quarter day celebrating the middle of fall.

Naked-eye Planets

The Sun, Moon and planets rise in the east and set in the west due to Earth’s west-to-east rotation on its axis.

Evenings: Venus (setting low in west), Jupiter (rising in the east), Mercury (west, late in month)

Mornings: Mars (east), Jupiter (east), Mercury (early in month)

* Mercury emerges low in the west late in the month.
* Venus is climbing higher daily, becoming the prominent “evening star” in the west.
* Mars is up in the east well before sunrise.
* Jupiter rises in the early evening and is high in the west by morning.
* Saturn is now hidden in the Sun’s glare.

Lyra (Credit: Scott Roy Atwood)

Constellation of the Month: Lyra the Lyre

Lyra the Musical Lyre is a small constellation just to the west of Cygnus the Swan and the Milky Way. Being rather northerly, it is visible in our evening skies over half the year, from June through December. While it may not look like a musical instrument, its shape is distinctive – a parallelogram hanging from an especially bright star, 1st-magnitude Vega, the fifth brightest star in the night sky.

It’s hard to miss Vega, being the most brilliant object nearly straight overhead in the early evenings of fall. Situated 25 light years away, Vega was made famous in the movie “Contact” based on Carl Sagan’s novel. In the story a radio astronomer, played by Jodi Foster, discovered a radio message from intelligent beings seemingly coming from Vega.

Vega also combines with the brightest stars of two other constellations, Deneb (in Cygnus the Swan) and Altair (in Aquila the Eagle), to form the large Milky Way Triangle (also known as the Summer Triangle) now high overhead.

In addition to Vega, Lyra also contains other jewels, two of which are Epsilon Lyri and the Ring Nebula. Epsilon Lyri looks like a rather ordinary star a finger-width (held at arm’s length) from Vega which binoculars show to be a double star. But that isn’t the whole story as a telescope at high power reveals each of those stars to be a double star, hence the star’s nickname, the Double-Double. These four stars, along with a couple of even fainter ones, form a multiple star system in which all the stars are gravitationally bound and orbit a common “center of gravity.”

Ring Nebula (M57) (Credit: Meyer Observatory, Central Texas Astronomical Society)

The Ring Nebula, also known as M57, is one of the most popular and well-known planetary nebula. The term is misleading as it has nothing to do with planets; rather it is the visible remnant of dead star. Through a telescope M57 looks like a tiny, faint grayish donut-shaped cloud while astrophotography displays its rich colors. Unseen at the center is a small, Earth-sized dead star called a white dwarf, the hot and still-glowing “corpse” of a giant star that died less than 2,000 years ago at a distance of 2,300 light-years. The visible cloud is the star’s outer shell of gasses that were blow away during the star’s last gasp of stellar life. The Ring Nebula gives a preview of what our Sun will look like when it dies in 5-6 billion years.

Lyra in Greek Mythology

Lyra is one of the 48 constellations from antiquity. In Greek mythology the harp-like stringed instrument belonged to Orpheus, the superbly gifted minstrel whose music and voice could charm people, tame wild animals and even change the flow of rivers. It was given to Orpheus by the god Apollo who taught him to play with the power of a god. Like Willie Nelson and his guitar, Orpheus and Lyra were widely traveled. They accompanied Jason and the Argonauts on their quest for the Golden Fleece, and saved the ship and crew from certain shipwreck by drowning out the sinister singing of the seductive Sirens with powerfully beautiful music.

Orpheus and Lyra charming the wild animals with music (Credit: An ancient Roman floor mosaic now in the Archeological Museum of Palermo, photographed by Giovanni Dall’Orto in 2006.

But alas, his life ended prematurely. His wife, the beautiful nymph Eurydice, died when bitten by a snake. Orpheus was so grief-stricken that, with lyre in hand, he climbed down into the Underworld to retrieve Eurydice. His music had such power that even Hades (Pluto) agreed to allow her to accompany him back to Earth – on the condition that Orpheus would refrain from casting his gaze upon her until they were completely out of the Underworld. Unfortunately, just before reaching Earth’s surface, he couldn’t resist glancing back to make sure she was still with him, and when he did, she immediately vanished and returned once again to the Land of the Dead.

The grief of losing his lovely young wife, not once but twice, was more than he could bear. Thereafter he forsook the company of all women, causing the wild women of Thrace, out of jealousy, to kill him. They threw his lyre into the river as Orpheus himself descended into the Underworld to spend eternity with his beloved wife, Eurydice.

Zeus, the king of the Gods, had Aquila the Eagle retrieve Orpheus’ lyre from the river and carry it into the sky where Lyra continues making music for the whole world to enjoy.

Astro Milestones

Oct. 4, 1957, the Russian’s launched Sputnik I, the first human-made Earth-orbiting satellite, beginning of the Space Age. Oct. 29 is the birthday of Edmund Halley (1656-1742), English astronomer of Halley’s Comet fame.

Star Parties

The Central Texas Astronomical Society’s simultaneous free monthly star parties are Saturday, Oct. 22, at the Lake Waco Wetlands, Belton’s Overlook Park on Stillhouse Hollow, and Hubbard City Lakes Park beginning at 7 p.m. CTAS also owns and operates the Meyer Observatory at the Turner Research Station near Clifton, Texas; the next monthly observatory open house is Saturday, Oct. 8, from 7-9 p.m. See www.centexastronomy.org for more information.

Paul Derrick is an amateur astronomer who lives in Waco. His website (www.stargazerpaul.com) contains an archive of past Stargazer columns, a schedule of his upcoming programs, star parties and classes, and other basic stargazing information. Contact him at: paulderrickwaco@aol.com, or 254-723-6346, or 918 N. 30th St., Waco, TX 76707.