By Dr. Bob Doyle, Frostburg State Planetarium

Garrett County Skies for October 2018

Venus vanishes, Jupiter drops, Mars in South at dusk and Hunters’ Full Moon on October 24

October opens with an Oakland sunrise at 7:13 a.m. and a sunset at 7:02 p.m. Daily sunlight then lasts 11.8 hours. Each day, the sunrise comes a minute later while the sunset comes about 1.5 minutes earlier than the previous day. In October, the sun appears in front of the stars of Virgo so that star group is hidden in the twilight glow. October ends with sunrise at 7:44 a.m. and sunset at 6:18 p.m. Daily sunlight then lasts 10.5 hours. Twilight before sunrise and after sunset lasts about an hour each.

In early October, the moon is in the morning sky, appearing half full (like a reversed ‘D’) in the southern dawn on October 2nd. Late on October 8, the moon’s motion carries it from the morning to the evening side of the sun (New Moon). On October 11th, a slender crescent moon appears above the bright planet Jupiter low in the western dusk. On Sunday, October 14th, a crescent moon will appear above the planet Saturn in the evening hours. On October 16th, the evening moon will appear half full (like a ‘D’) with its right side lighted by the sun. Along the moon’s straight edge, the sun there is rising, lighting the crater rims and elevations. The evenings of October 15-17 are the best for spotting the moon’s surface features with a telescope. The moon will pass over the planet Mars; appearing to the right of Mars on the 17th and to the left of Mars on the 18th. The moon is full on October 24, appearing opposite to the sun and rising about sunset. This is the Hunters’ Moon as it offers extra moonlight in the two evenings that follow. In the 1700’s and 1800’s , hunters used this moonlight to spot animals moving across the freshly harvested fields. On Halloween (Oct.31), the moon will appear half full (like a reversed ‘D’) in the southern dawn.

The beautiful evening ‘star’, the planet Venus will disappear from the western dusk in October. On October 26, Venus will pass south of the sun.  You will next see Venus in late November when it appears in the southeastern dawn. The planet Mercury is at too low an angle to the sun to be seen in October. The bright planet Jupiter is appearing a little lower in the Southwest each evening. Jupiter is setting two hours after sunset at the start of October which will shrink to an hour at month’s end. The planet Saturn is higher and to the left of Jupiter. Saturn sets about 10 p.m. in early October,  which drops to 9 p.m. as October ends. Mars is well positioned in the South in the early evening hours of October. You can distinguish Mars by its yellowish tint. Mars appears in the star group Capricornus.

The brightest star formation or asterism on October evenings is the Summer Triangle, a huge trio of bright stars in the West. On lower right side of the Triangle is the bright white-blue star Vega. Vega’s light has travelled for 25 years to reach us. So we see Vega as it was 25 years ago or in 1993. High above Vega is a moderately bright star – Deneb, the most remote triangle star at a distance of 1400 light years. Deneb is about 50,000 times more powerful than our sun and is classified as a yellow supergiant star.  On the left side of the Triangle is Altair, the closest of the Triangle stars at a distance of 17 light years. From a study of Altair’s light or spectrum, we know that Altair rotates rapidly and has th shape of a hamburger bun.