April 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 April 15th. For April, your best viewing nights will be from April 3rd to the 18th. The Star chart below is set for Florence, SC on April 15th at 9 pm. Note: A new table of contents for earlier columns is located in this January 2018 column.

The Virgo Cluster:
As you know, many times I will repeat a column. Usually I feel that it is an important topic, and at least five years have passed since I discussed the subject. Another reason, is that it is timely. In this case, April is indeed the best month of the year to observe the Virgo Cluster. Searching the Virgo Cluster will require that you have large binoculars, 20 to 25 power, or a Dobsonian telescope; most simple refractors will not suffice. If you have been trying to work through the Messier Objects list, you can find at least fifteen Messier Objects in this small area of the spring sky.

The Virgo Cluster is not a star cluster, but is a cluster of galaxies; the month of April is usually the best time to view this target. Data from the Hubble telescope estimates there are as many as 1500 galaxies associated with this cluster. This galaxy cluster is also referred to as the Virgo/Coma Bernice’s Cluster.

If you attempt to venture into this realm of galaxies, you are somewhat limited to using a reflecting telescope, preferably a 4 inch or larger Dobsonian, or large binoculars, such as 25 X 100 mm. A 100 mm binocular is actually the same size as a 4 inch refracting telescope. However, dim objects such as galaxies are surprisingly more defined through the binoculars using your two eyes than with the equivalent telescope with one eyepiece.

As always when attempting to find galaxies you must find a dark sky location. In our area of the country, five to ten miles outside of any modest size town should be sufficient for your search of the Virgo Cluster. A great viewing location is Lynches River Park. However, unless you are camping at the park, or coming to a Lynches River Star Party, you are not allowed to just bring your telescope to the park. The best choice may be to find a friend or relative who owns farm land.

Once you have chosen a good viewing location, first find the location of the Virgo Cluster, see circle below.

Next, check out the area circled with ten power binoculars. The image below is a good example of what you may see.

So where are the galaxies? With normal 7-10 power binoculars, this region looks like a simple star field. If you look carefully, you may note that several “stars” are somewhat larger and fuzzy. These small fuzzies are some of the many galaxies in the Virgo cluster. Next aim your reflecting telescope near the center of this region shown in the circle above. Starting at about 25 power, while looking through the eyepiece, slowly move your scope outward in an expanding spiral. Every few minutes check you telescope finder to make sure you have not drifted outside the Virgo Cluster region of the sky. This roaming technique is quite different from the normal careful searching for a specific target in the sky. If you have chosen a good dark sky site, and you are careful and patient, you should be able to see many small fuzzy galaxies. This next image is what you may see through your telescope. The yellow circle is the field of view at about 30 power and contains three Messier Objects. This image also shows the locations of various other cataloged galaxies. These objects are dimmer than the Messiers, and are assigned a NGC (New General Catalog) number.

The following image is how you could see the Virgo Cluster if you owned expensive astronomy equipment and used long exposure astrophotography.

What I have briefly described above is how to casually visit the Virgo Cluster of galaxies. If you are a serious Messier Object searcher, then you must revisit the Virgo cluster with more care. There are a total of fifteen Messier Objects near the center of the Virgo Cluster, and three others nearby. You will need a good star chart or computer program to start your search. Below is the star chart that I used to check off each Messier as I personally searched this region. As you can see, the chart lists Messiers, NGC objects and many too dim to be labeled objects in the Virgo region. I started with Messier 60 and ended with M49; logging fifteen Messiers in one April night’s viewing.

From M60 to M49, the black line/arrow shows the exact path I used that night as I worked my way through the cluster. I used 25 X 100 mm binoculars to locate all these objects.

Now it’s your turn.

Naked Eye Sights: Venus returns in the west as the Evening Star.

Binocular Sights (7 to 10 power): Go to the Virgo Cluster and try to see if any “stars” are fuzzy. You will need a very dark sky site to do this with simple binoculars.

Big Binocular Sights (18 to 25 power): Go to the Virgo Cluster and see how many galaxies you can find. Remember they will still be small fuzzies.

Telescope Sights (60-100mm): Jupiter returns low in the eastern sky towards the end of the month.

Dobsonian telescope (6 -8 inch): Try to get a closer look at some of the many galaxies in the Virgo Cluster.

See you next month!















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