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 July 15th. For July, your best viewing nights will be from July 8th to the 20th. The Star chart below is set for Florence, SC on July 15th at 9 pm.
The most important astronomy event of the year occurs on July 14th. However, you will not be able to view it with your telescope, binoculars or naked eye. The event is the arrival of our spacecraft New Horizons at the dwarf planet Pluto. To date most of the images of Pluto have been generated by the Hubble telescope and are quite blurry and unresolved. Although good imaging of Pluto is not possible using the Hubble telescope, it is amazing that we have been able to locate five moons circling Pluto. In 1978, long before the Hubble telescope, the first and largest moon of Pluto, called Charon, was discovered; using a telescope at the US Naval observatory. By 2012, using the Hubble telescope four more moons were also found; see image below.
A brief background about Pluto: By the late 1800’s, astronomers felt that there was another planet out beyond Neptune’s orbit that was causing some disturbances to the orbit of Uranus. This “Planet X” was finally discovered in 1930, and called Pluto. Later information proved that Pluto was too small to have any effect on Uranus, and thus the whole Planet X/Uranus theory was disproven. Therefore, it was only by accident that Pluto was discovered and not because of theoretical calculations. Below is an image of the actual photos they used in 1930 when they discovered Pluto.
So for seventy-six years our Sun had nine official planets. In 2006 it was decided that Pluto would be reclassified as a dwarf planet. The primary reason for the reclassification was that other small planet-like objects were being discovered beyond Pluto, and one called Eris was larger than Pluto. To prevent a constant upgrading of the number of planets circling our Sun, new rules were written for planet classification. These new rules determined that Pluto and the Pluto-like objects beyond would now be called dwarf planets. The new classification rules also resulted in the largest asteroid Ceres becoming a dwarf planet; note: a spacecraft called Dawn has recently been placed in orbit around Ceres. Below is an artist’s comparison of the Earth to Pluto and three of its moons.
The New Horizon’s spacecraft was launched on January 2006 to begin its nine year and 3 billion mile journey to Pluto. As the spacecraft approaches Pluto it has been sending back images. The images below were taken by New Horizons in late June 2015. On the left is Pluto and Charon, and on the right are two images of Pluto. Note on the Pluto images, a bright spot has been detected. In a few weeks, we should know what it is.
On Tuesday morning July 14th just before 8 am, the New Horizons spacecraft will make its closest approach to Pluto, flying only 7,770 miles above its surface. The fact that tiny Pluto has at least five moons raises suspicions that Pluto may have many other small moons. Indeed, Pluto may be a ringed planet. The answers will be known in only a few weeks.
Pluto Facts and Trivia:
Percival Lowell at the Lowell observatory in Flagstaff, Arizona spent the last several years of his life trying to locate this Planet X. After his death, the job was later given to a young 23 year old Clyde Tombaugh. After searching for a year, the new planet was discovered in 1930.
The naming of Pluto caused great discussion. The final name came from a suggestion by an eleven-year-old girl in England. One of the reasons it was liked is that the first two letters, PL were Lowell’s initials. Obviously Walt Disney was impressed and named his newest cartoon dog character after the planet.
Eight years after the discovery of the planet Uranus, in 1781, a new element was discovered and named Uranium in honor of the planet. In 1940 element 93 was discovered and since it was the next element after Uranium, it was named for the next planet after Uranus, Neptunium. Finally in 1941 Element 94 was discovered and therefore took the name of the next planet out, Plutonium.
Pluto does not orbit in the same plane as the rest of the planets. Pluto’s orbit is so irregular that it spends part of the time closer to the Sun that Neptune. From 1979 until 1999, Neptune was the farthest planet from the Sun. However, Pluto will never intersect/collide with Neptune.
Radio signals take four and a half hours to travel to the spacecraft from Earth as it approaches Pluto.
From May 2015, onward, the resolution of images taken by New Horizons exceeds those of the Hubble Space Telescope
Clyde Tombaugh died in 1997, and some of his ashes are on board the New Horizons spacecraft.
Naked Eye Sights: Look to the south for the bright summer Milky Way passing through Scorpius and Sagittarius.
Binocular Sights (7 to 10 power): Scan the regions near the tail of scorpion, and then upwards along the Milky Way to see high concentrations of stars, nebulae and star clusters.
Telescope Sights (60-100mm): That bright object in front of Scorpius is Saturn, your best target of the month. If you have a 10-inch or larger telescope, and patience, you can search for the planet Pluto in Sagittarius. You must use a good astronomy program such as Starry Night, and you must realize that this is a difficult task.