Sky events for September 2012
Sept. 1 – Sunrise at 6:21 a.m.; sunset at 7:34p.m.
Sept. 8 – Last quarter moon in Taurus with Jupiter in the morning.
Sept. 8 – “Star Trek” premieres in 1966.
Sept. 9/10 – Epsilon Perseid meteor shower peaks.
Sept. 10 – Mercury in superior conjunction (behind sun).
Sept. 12 – New moon in Leo with Mercury and the sun.
Sept. 22 – Fall equinox occurs at 2:41 p.m.
Sept. 23 – J.G. Galle discovers Neptune (1846).
Sept. 29 – Uranus brightest for the year (5.7 magnitude).
Sept. 31 – Sunrise at6:55 a.m.; sunset at 6:40 p.m.
Highlights for September 2012
If you missed the Perseid meteor shower in August, you’ll have another chance in September. This shower remains active from Sept. 4-14, but peaks on the night of Sept. 9 when you should spot about five shooting stars per hour from 11 p.m. to 12:30 a.m. The waning crescent moon rises about 12:40 a.m. to wash out the dimmer meteors. In 2008, this shower had an outburst that may happen again but only if you are watching.
Neptune reaches opposition the end of this month, meaning it rises in the east as the sun sets in the west, thus is up all night on Sept. 29. All month, Uranus will appear the brightest for the year at about 5.7 magnitude. This means Uranus is just bright enough to see with the naked eye if you are in a spot with no light pollution and can easily be seen with a binoculars or even a small telescope. Uranus can be located between the constellations of Pisces (the fish) and Cetus (the sea monster) near bright star 44 Piscium. The best way to watch Uranus, a comet, or an asteroid is to watch it night after night as it moves in relation to the star 44 Piscium.
If you have a set of binoculars enjoy simultaneously looking at Venus about half-way between the moon and a cluster of stars, called the Beehive cluster (M44) in Cancer, on during the predawn hours of Sept. 12. And if you have a telescope, enjoy watching Comet Linear (10th magnitude) move through Bootes (behind the handle of the Big Dipper) mid-September on. Even brighter (ninth magnitude) Comet Parthenope (the mermaid) as she swims through southern Aquarius all month.
Bodes Law and Distances of Planets
The last and greatest star atlas of the Golden Age of celestial atlases, Uranographia, was published by Johann Elert Bode in 1801. But Bode is better remembered for a footnote in a work that he published about an easy formula to determine the distances from the sun to each major known planet at the time. The formula was actually derived by Johann Daniel Titius in 1766 and in its original form went like this: d = ( n + 4 )/10 where d is the distance from the sun to a planet and n is the sequence of numbers 0, 3, 6, 12, 24, 48, 96, etc.
It is now often called the Titius-Bode Law. When I use it, I start with Earth at the number 6. You see 6 + 4 = 10 and 10/10 = 1 which is the definition of an Astronomical Unit (or AU, the average distance of the Earth from the Sun is 1 AU). Then I double 6 to get 12 + 4 = 16 and 16/10 = 1.6, the distance in AUs to Mars; then double 12 to get 24 + 4 = 28 and 28/10 = 2.8 AU of the distance of the Asteroid Belt from the Sun; then double 24 to get 48 + 4 = 52 and 52/10 = 5.2 AUs to Jupiter and double 48 is 96 + 4 = 100 and 100/10 = 10 AUs to Saturn, etc. Going backwards, half of 6 is 3 + 4 = 7 and 7/10 = 0.7 AU to Venus from the Sun but halving 3 does not give a whole number so Titius had to start with 0 + 4 = 4 and 4/10 = .4 AU is the distance of Mercury. It was using this pattern that caused astronomers to look for and eventually find the Asteroid Belt and Uranus.
Early history of length
Since the ancients thought of the planets, moon, and sun as gods, free to move among the backdrop of fixed stars, it is not surprising they may have been originally used the night sky for standardizing length long before lengths like foot and yard were the same for everyone (standardized). For instance, if any size person broke a stick so that when held at arm’s length it stretched from Procyon (the 8th brightest star seen from Earth) and Gomeisa (the only bright star next to Procyon), every size person would have a stick pretty much the same length (the small cubit at the time).
Egyptologists have figured out that the origin of the their cubit and royal cubit, to build the Pyramids, actually are related to a right triangle joining the sun to the average Earth distance (one leg, the cubit) and the other leg connecting the Earth to Mars, when Mars is at its average distance from the sun (the royal cubit), and the hypotenuse from the sun to Mars. The ratios of the above lengths fit the pyramid ratios exactly. We currently have standardized the meter as being 1,579,800.298728 wavelengths of helium-neon laser light in a vacuum. GNATS
Editor’s note: Paul Konichek teaches math, astronomy and physics at SPASH. GNATS is the acronym for “go now and teach someone.”