May 2017

                               Tony Martinez

Each month I will describe sights of interest in the night skies of South Carolina. These sights will be broken down into four sections; what you can see with the naked eye, with binoculars, with a small refracting telescope and with a Dobsonian reflector. 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 May 25th. For May, your best viewing nights will be from May 14th to the 29th. The Star chart below is set for Florence, SC on May 15th at 9 pm. Note: A table of contents for earlier columns is located in the May 2016 column.

The May 2017 Sky:
This month we will focus on one section of the southern sky as shown in the squared off section of the star map above. You can enjoy this area of the sky with your eyes, binoculars, and small and large telescopes. Below is a larger view of this region.

Leo: Starting with naked eye targets. The most obvious is the constellation Leo the lion. Leo is the most prominent constellation of spring. In addition, the shape of the constellation does indeed look like a crouching lion. The brightest star is Regulus representing the front leg of the lion, however, all nine stars that define the constellation are easily visible to the naked eye even with our local light pollution. The head and mane of the Leo is known as the “Sickle” asterism or the backwards question mark. Leo contains five Messier Objects, all located just below the lion.

Jupiter: This spring, the brightest star-like object is the planet Jupiter located in the southeast. Jupiter is a favorite planet because with a small amateur telescope you can see the planet as a disk, see its four major moons, and in addition, you should be able to see Jupiter’s clouds bands, usually in color. If you have not yet purchased a telescope, with simple binoculars braced against a building or car, you can easily see the four major moons of Jupiter, as small pinpricks of light. Remember, on any given night, one or more of these moons may be in front or behind the planet.

Arcturus: The brightest star in this field of view is the orange star Arcturus. If you are not sure you are looking at Arcturus, go to the main star chart at the top of the page. Starting at the bowl of the Big Dipper, follow the curve of the handle, and it will point to Arcturus; known as “Arc to Arcturus.” This is not just another bright star in the night sky; Arcturus is quite unique versus all the other stars visible in the night sky. All of the naked eye visible stars in the sky are moving together in the rotating Milky Way, except one star, Arcturus. Arcturus is not moving along with the other stars in the Milky Way, it is plunging perpendicular through the Milky Way. I good analogy to describe this is as follows. Imagine standing on a bridge spanning the Great Pee Dee River in late autumn and looking down as fallen leaves float along down the river. These leaves are carried along as the stars are carried along the spinning Milky Way. Now drop a small stone off the bridge into the river; this would represent how Arcturus is moving through our galaxy.

The Milky Way rotates once every 250,000 years, so after one rotation, the star Arcturus will no longer be visible to the naked eye. You may wonder why there is only one star moving in this manner. There are at least 50+ other stars moving this way along with Arcturus, but they are too dim and far away to be seen with the naked eye.

There is another interesting fact about Arcturus. Using technology available about 100 years ago, it was determined that Arcturus was 40 light years away. Now, in 1893 there was a World’s Fair in Chicago. In 1933 there was another World’s Fair in Chicago; 40 years later. Some brilliant person had a great idea. When the World’s Fair closed in 1893, the light from the star Arcturus began its journey to Earth, arriving in Chicago 40 years later. The light from Arcturus in 1933 was focused on a photoelectric cell, and used to turn on the power for the opening of the new World’s Fair. Many years later, data showed that Arcturus was actually 37 light years away; however, it was still a great idea.

Virgo Cluster: Below Arcturus, and above Jupiter is a region of the sky known as the Virgo Cluster. Usually clusters refer to clusters of stars, but the Virgo Cluster is a cluster of about 1500 galaxies. Many of these galaxies are visible through large binoculars. The best choice is to point your Dobsonian into this area, and slowly scan this region. For the Messier Objects hunters, there are fifteen Messier Objects in the Virgo Cluster. Below is a view of a small section of the cluster.

For a good overview of the Virgo Cluster, go back in my blog to April 2012.

M104 (The Sombrero): My personal favorite target in this area is Messier 104, also known as the Sombrero Galaxy.

This beautiful edge-on galaxy can be detected with simple binoculars, but only as a tiny smudge. I have seen the central dark band with my 25 X 100mm binoculars.

For a good overview on locating M104, go back in my blog to March 2011.

Naked Eye Sights: Leo the Lion, Jupiter, and Arcturus

Binocular Sights (7 to 10 power): Jupiter’s four major moons. Possibly a few galaxies in the Virgo Cluster, and possibly the tiny smudge M104.

Telescope Sights (60-100mm): Jupiter. Try for some more Virgo Cluster galaxies, and M104.

Dobsonian telescope Sights (6 -8 inch): Jupiter. The best choice for the Virgo Cluster and M104.

See you next month!

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