May 2018

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 15th. For May, your best viewing nights will be from May 4th to the 18th. The Star chart below is set for Florence, SC on May 15th at 9 pm.  Note: A new table of contents for earlier columns is located in this January 2018 column.

Deep Sky Objects (DSO’s):
As a lifetime amateur astronomer, I often inform people that I am not a lunar astronomer, or a planetary astronomer.  Instead, my fun is observing deep sky objects.  A deep sky object is any object that is located outside of our solar system, but not another star.  I continually mention searching for Messier Objects. The Messier Objects list is essentially a list of deep sky objects. This list contains 110 or 109 objects; most astronomers accept 109, but some feel 110 is correct. Only one Messier Object is not a deep sky object; Messier 40. M40 located in Ursa Major is a line of sight (not true) double star. Messier stated that an earlier astronomer, Hevelius, reported a nebula in Ursa Major. Messier found the object and reported that it was a double star not a nebula, and then for some unknown reason, he added this double star to his famous list of comet-like deep sky objects; M40.

Over the years, I have only mentioned the Messier list for amateur astronomers. However, there are other notable lists available. A gentleman Patrick Moore felt that once amateur astronomers completed the Messier list, they would want more. Moore noted that Messier left out some great amateur targets, such as the Double Cluster in Perseus. In addition, Messier was limited by latitude because he made his observations from Paris, France. With this in mind, Moore made up a new list of deep sky objects covering both the northern and southern hemisphere. In addition, he purposely listed 109 objects, and named it the Caldwell Catalog; published in 1995. Example: the Double Cluster is C14.  The good news is if you want to complete the Caldwell Catalog, you will have to take a vacation toward the equator.

Finally, there is a massive list of deep sky objects with the prosaic name “New General Catalogue.” This list contains 7,840 objects, known as the NGC objects. Some later updates to this list were called Index Catalogue objects; IC objects. This massive list was completed near the end of the 19th century, and the updates in the early 20th century.  A total of 106 Messier Objects have NGC #’s, two have IC #’s, and two have no other designation: M40 and M45. All but two Caldwell Objects have NGC/IC designations.

In conclusion: The Messier list is still the best place for new amateur astronomers to go. Next is the Caldwell Catalogue. Finally, the NGC and IC lists are for high end amateurs and professional astronomers.

There are three types of deep sky objects for your viewing enjoyment, nebulae (gaseous, planetary and dark), star clusters (open and globular), and galaxies. Throughout my many columns, I have pointed out a multitude of deep sky objects that you might enjoy. This month, try to observe the following two; the first is easy, and second is difficult.

The Hercules Cluster (M13, NGC 6205):
This is a globular star cluster is in the east in the constellation of Hercules. The location of the cluster is shown in the image below.

Start by trying to see it with binoculars first. It should look like a blurry star. Move on to your telescopes. Consider yourself successful if you can resolve some individual stars.  Your best view will usually be with an eight inch or above Dob, but it is an easy target with any scope. Below is M13 seen through a large Dob.

The Sombrero Galaxy (M104, NGC 4594):

The best way to locate this beautiful deep sky object is to find the constellation Corvus low in the southern sky; see below. This four star trapezoid is easy to locate. Find the star farthest to the left, called Algorab. Next move to the left of Algorab and slightly up until you see a small triangle known as the Star Gate. You may not be able to clearly see the Star Gate, but what should be obvious is a small line of about four stars to the left of the Star Gate. These “pointer” stars point directly to M104.

When you find M104 with binoculars or a small telescope, it will not look like the beautiful image shown above. Instead, it will look more like the image shown below.

Naked Eye Sights: Watch in the west as Venus rises this month. Look to the east as Jupiter moves upward this month. Throughout the year there are nice flyovers of the International Space Station (ISS); check out the flyover 9:37 pm on the evening of May 20th, very bright and high in the sky.

Brightness Start Highest point End
(mag) Time Alt. Az. Time Alt. Az. Time Alt. Az.
18 May -0.6 05:10:20 10° N 05:12:18 15° NNE 05:14:17 10° ENE
19 May -1.8 20:56:13 10° SE 20:57:19 11° SE 20:57:29 11° ESE
19 May -1.1 22:30:14 10° WSW 22:30:36 13° WSW 22:30:36 13° WSW
20 May -1.7 05:00:59 10° NNW 05:03:56 30° NE 05:06:51 10° E
20 May -4.0 21:37:38 10° SW 21:40:52 72° SE 21:44:07 10° NE

Binocular Sights (7 to 10 power): Jupiter’s moons.

Big Binocular Sights (18 to 25 power): Jupiter, M13 and M104

Telescope Sights (60-100mm):  Jupiter and M13.

Dobsonian telescope (6 -8 inch):  Jupiter. M13 cluster and M104.

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