January 2010

Tony Martinez

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 January 15^th. For January, your best viewing nights will be from January 5^th through January 20^th. The Star chart below is set for Florence, SC on January 15^th at 9 pm.

The Triangulum Galaxy:

The Triangulum Galaxy is a spiral galaxy usually referred to by its Messier #, M33. Its name is derived from its location in the Triangulum constellation. This is one of only two galaxies considered close to our Milky Way Galaxy. Close is a long way off; almost 3 million light years. The second “close galaxy” is the Andromeda Galaxy M31 featured in last October’s column. So this month I want to challenge my amateur astronomy readers to find our other neighbor, M33, shown below.

The Andromeda Galaxy is about 2.5 million light years away, and it can be seen with the naked eye in a dark location. However, what we usually see with the naked eye or with binoculars is the bright center of the Andromeda Galaxy, and not the faint large spiral. Although the Triangulum Galaxy M33 is only slightly farther away than the Andromeda Galaxy, it has no bright central core. So you will need the right equipment, and near perfect viewing conditions to see it at all! It has been reported that M33 is visible to the naked eye in remote dark regions of the world. It is also interesting to note that there has never been a historical report of this galaxy before the invention of the telescope. Obviously, in ancient times there was no light pollution, or industrial pollution to interfere with viewing the heavens. Therefore, the ancient Egyptians or Chinese should have reported seeing M33. What we can conclude from this information is that M33 is so faint; you can only see it with the naked eye if you know that it exists.

First, the necessary viewing conditions: There are various indicators of a good night to view galaxies. One indicator is that you must be able to see all seven stars of the Little Dipper. Another good indicator is seeing stars inside of the bowl of the Big Dipper. If you can see stars in the Big Dipper’s bowl, most likely you can see M33. Finally, check out my October 2009 column about viewing the Andromeda Galaxy. If you can see the entire Andromeda Galaxy, then you can see M33.

Next, the viewing equipment: A simple refractor will not do. If you have a medium to large Dobsonian, you may pull it off with a 42 mm 2-inch eyepiece. However, the best chance to view M33 is by using two eyes. Therefore, binoculars are your best choice. A pair of 70-100 mm binoculars is best, but you should be able to see M33 with 7 or 10 X 50 binoculars. In addition, it’s good to have a feel of the relative size of M33 as seen through your binoculars. M33 will be slightly larger than the width of two full Moons; see comparison of the Moon versus M33 shown below.

Last is where do you look. M33 is in the region of the sky near M31, the Andromeda Galaxy, so first find M31 before you begin your search for M33. Next you have to check out star charts; below is a chart to direct you to the area of M33; set for 9 pm on January 15^th.

Since you will only attempt to find M33 on a good viewing night, it will be easy to see the constellation Triangulum. Look to the left of Andromeda, or to the right of the Pleiades to find the distinctive “triangle.” This time of year, the triangle looks like an arrow pointing down and to the left; towards the southwestern horizon. Now that you found the triangle, use the star Rasalmothallah, the “point of the arrow” as a marker to find M33. Find Rasalmothallah with your binoculars, and move slightly down and to the right; remember the size of M33 versus the full Moon. Another aid is the star Mirach in the constellation Andromeda. This star is usually used to help you star hop to the Andromeda Galaxy. M33 is about half way between Mirach and Rasalmothallah.

Personal note: I have seen M33 on two occasions, both at a dark sky park in north central Pennsylvania, called Cherry Springs Park. Both times I used 25 X 100 mm binoculars. The first time, I had the binoculars aimed directly at M33, and saw nothing, and then suddenly it appeared, like a faint ghostly image in the sky. Indeed, if I didn’t know it existed, I would not have noticed it at all. So look for a very faint spiral galaxy, not at all as bright as the images above. Below is a representation of how I first saw M33.

Naked Eye Sights: There are two nice ISS (International Space Station) flyovers this month. Use the information on the charts below. Notice there is a good flyover on January 5^th, starting in the southwest at 6:10 pm ending about 5 minutes later in the northeast. The second one is on January 23^rd, starting at 6:23 pm.

Binocular Sights (7 to 10 power): M33, the Triangulum Galaxy.

Telescope Sights (60-100mm): The planet Mars returns to the night sky. Look for it in the southeast, especially in the last half of the month. By the end of this month, it will be the brightest it’s been in two years. If you have a “good” telescope, you may be able to see the north polar ice cap of the planet.

See you next month!