August 2014

It is mid-summer already! By month’s end there will be a few breaks from the sweltering weather as fall approaches, darkness comes noticeably earlier than last month, and the summer sky is still in view in the early evening. August represents a second chance to observe objects and constellations that might have been missed last month.

CONSTELLATIONS

My intent in this section has been to cover the new constellations that come in to view at nightfall each month. I may have gotten a bit ahead last month, so there are only three new constellations to cover this month. I will cover two zodiacal constellations, Scorpius and Sagittarius, and the northern constellation of Draco. A planosphere or smartphone app like Google Sky Map can help determine where to look to find each constellation, and a Wikipedia link is provided to further aid in identifying each constellation’s appearance.

Scorpius (The Scorpion)
Scorpius is, in my opinion, the most beautiful of the zodiacal constellations. Look for this constellation to he east, or left of, Libra. The head, long slender body, curling tail, and stinger can be seen. This is the southernmost of the zodiacal constellations, which tends to leave the tail hanging below the horizon for us northern latitude observers. Southbound travellers in August should make it a point to find this constellation. It is well placed in the sky where I grew up in Georgia, and is spectacular from southern Florida or Hawaii.
http://en.wikipedia.org/wiki/Scorpius

Sagittarius (The Archer)
Sagittarius a rather easily observed constellation that is located to the east, or left of, Scorpius. Most observers can readily recognize the constellation as the teapot asterism. By tilting one’s head toward the left shoulder, imagine the handle as the archer’s head, the lid is the bow, the pot is the thorax, and the spout (kinda) represents the legs. This constellation has the distinction of being in the direction of the center of the Milky Way galaxy. As such, it is worth taking the time to scan this constellation with binoculars or a small telescope.
http://en.wikipedia.org/wiki/Sagittarius_(constellation)

Draco (The Dragon)
Draco is a large, but difficult constellation of rather dim stars in the northern sky. Draco’s tail starts near the northernmost pointer star of the Big Dipper, and it roughly parallels the curvature of the Big Dipper handle before curving under the Little Dipper and turning back toward the south, and then terminating at the dragon’s head. The best chance of seeing this constellation will be under a very dark sky.
http://en.wikipedia.org/wiki/Draco_(constellation)

SOLAR SYSTEM OBJECTS

The Sun. As August is the midsummer month, the days are already beginning to grow shorter at a faster rate. Last month, Sun rose 21 minutes later and set 17 minutes earlier at the end of the month than it did at the beginning of the month, meaning that by July’s end a day was only 38 minutes shorter than it was at the beginning of the month. By the end of August, the Sun rose 38 minutes later and set 40 minutes earlier than at the end of the month than it did at the beginning of the month. During August, days were shortened by 78 minutes compared to 40 minutes in July. One can detect that the slope of the August section of the ecliptic is more negatively sloped than the July section by examining the star chart below. The reasons why the rate of change for the length of a day change through the seasons is a fascinating topic that I will follow for the next few months

Flown Verson of LM G&N Dictionary, Apollo 11, pg S1, May 29, 1969. Private Collection. Scan courtesy of Larry McGlynn. www.hq.nsa.gov/alsg/a11/A11StarCharts.html Annotations in green and red by Jim Johnson.

Lunar Calendar

August 2 Very close conjunction with Mars
August 3 Very close conjunction with Saturn
August 4 First Quarter
August 10 Full Moon
August 17 Last Quarter
August 23 Conjunction with Venus and Jupiter
August 25 New Moon
August 31 Conjunction with Mars and Saturn

 

The Planets

Venus rises shortly before sunrise throughout the month, but become increasingly difficult to see by month’s end as it begins to get lost in the Sun’s glare. It is the brightest object in the eastern sky in the pre-dawn hours, and is still situated above and to the right of the sunrise point. It will slowly decrease in brightness as it continues its orbital journey toward the far side of the Sun for Earth’s perspective.

Mars remains in Virgo, and is the bright reddish colored object appearing in the southwest after sunset.

Jupiter emerges from the Sun’s glare to become a morning object in the east. It can seen as a bright object in the east shortly before sunrise, located above and to the right of the sunrise point. Recall that Jupiter was tracked as an evening object from the inaugural edition of Scope Out in April until it disappeared into the Sun’s glare in late May through early June. As a point for future study, I will write about the progression an exterior planet’s apparition as it emerges from the Sun’s glare as a morning object until it disappears back into the Sun’s glare as an evening object. What goes around comes around!

Saturn remains in Libra, and is the bright yellowish object appearing in the southwest after sunset.

DEEP SPACE OBJECTS (DSOs)

The Milky Way was covered extensively in last month’s Scope Out. The galactic center, which is located in direction of Sagittarius, is slightly higher above the horizon this month, so it is worth observing again for observers who happen to be in a dark sky location. Keep in mind that the Milky Way provides a background for Sagittarius’ much closer stars.

I pointed out the Bee Hive Cluster (M44) in Cancer and the Hercules Cluster (M13) n Hercules in May and June respectively. These objects are densely packed globular clusters. This month I offer M29, an open star cluster, for comparison. Observable through a moderate amateur telescope, stars appear brighter and more densely situated than the surrounding stars, giving the sense that the stars are related even though they are not as densely packed as other open clusters. It is found in constellation Cygnus just south of the star representing the intersection on the horizontal and vertical components of the Northern Cross asterism in Cygnus.
http://en.wikipedia.org/wiki/Messier_29

EVENTS

August 10th – SuperMoon.
The largest full Moon of the year occurs at about 1:30pm on August 10th. The Moon does not rise above the horizon until just before 7pm, but it is still very nearly full at that time. A supermoon is said to occur when the Moon is full at the same time it is near perigee, or when it is at its closet approach to Earth during its orbit.
http://en.wikipedia.org/wiki/Super_Moon

August 12th and 13th – Perseid Meteor Shower.
This normally showy meteor shower will be somewhat diminished by the nearly full Moon. It is best observed between midnight and dawn, and the meteors will seem to radiate from a point located in the constellation Perseus. This shower is still worth watching as many bright meteors are expected to be seen.
http://en.wikipedia.org/wiki/Persieds

August 18th – Conjunction of Venus and Jupiter.
The actual conjunctions, the two planets’ closest approach to one another, occurs before they rise right before dawn. At conjunction, they are separated by .2 degrees. Their separation will have increased to .5 degrees, the width of the full Moon, and will still present a pretty pair when they rise in the east shortly before sunrise.

© 2014 James R. Johnson.