Friday, April 8, 2011

April 2011

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 April 3rd. For April, your best viewing nights will be from April 1st through April 9th and April 22nd through April 30th. The Star chart below is set for Florence, SC on April 15th at 9 pm.

Saturn:

The return of the planet Saturn to the evening sky is a noteworthy event this year. Every year Saturn is visible at some point as the Earth makes its circuit around the Sun. However, since 2009, the evening arrival of the planet Saturn did not give the usual impressive view. As you know, Saturn is the favorite planetary target because of its spectacular ring system. Over the years as Saturn tilts in relation to us, we see the rings at differing angles. When the viewing angle is at or near zero degrees, the beautiful ring system fades from view; as occurred during 2009 and 2010. A classic Saturn image is shown below.

Of Course, the image you will see through your own amateur telescope will be quite small and sometimes blurry. To illustrate the angle extremes of amateur views of Saturn, below are two images taken through large amateur scopes; the one on the right showing zero degree ring tilt. The image on the right looks more like Jupiter than is does Saturn.

The bad news is that we have had two years of poor Saturn viewing; the good news is that the ring angle is opening back up. The better news is that Saturn will look more and more impressive each year forward peaking about 2017, but still quite impressive until 2022. The years 2024 and 2025 will be the next poor viewing years; see chart below. In reality, Saturn viewing is not as bad as it may sound. Over a period of 42 years, there are only four poor viewing years. If you purchased a telescope in 2009 or 2010, you can just consider it bad timing. You can now enjoy the rings of Saturn for several years.

I have viewed Saturn through my various telescopes all of my life, and I have also had many people look through my scopes. Throughout this time, I have always enjoyed it when someone looks through my telescope and sees Saturn for the first time; it is quite an amazing response. At various times last year, ScienceSouth had free public telescope viewing events using the ScienceSouth Dobsonian reflector and some of my own telescopes. We gave people the chance to see spectacular views of the mountains and craters of the Moon. Also last year people had a chance to view the planet Jupiter and its moons, plus they were able to see the cloud bands of Jupiter in color! Although these views generated various amount of excitement, I never heard the big “wows” I hear when someone sees Saturn for the first time. The big ball of Jupiter looks quite nice, and the small fuzzy ball of Mars is OK, and some people even enjoy the very fuzzy crescent of Venus; but Saturn is special. You can view hundreds of images of Saturn on the Internet, but there is something magical when your see it through your own eyes. So if you have a telescope, you can start viewing Saturn this month in the southeastern sky. Saturn will be in opposition on April 3rd at 8 pm. This only means that it will be at its brightest for the year. Good viewing of Saturn will continue from now through July. Saturn will leave its good evening viewing position at the end of July. As Saturn says goodbye, it will glide by the planet Venus low in the west early on the evening of August 6th.

To find Saturn this month, look to the southeast and you see the pale yellow planet. If you are in doubt about its location, then turn your eyes to the north. Find the Big Dipper, and then follow the handle of the dipper to “arc to the star Arcturus” then continue this arc and “speed on to Spica.” Saturn will be the bright object above Spica. If you have dark skies, you will be able to note the contrast of the blue star Spica with the yellow planet Saturn. Below is the position of Saturn in relation to these two prominent stars in early April.

So what should you expect to see? With standard 7 (or 10) X 50 binoculars, Saturn will still look like a star. With 15 power binoculars (tripod needed) it will look like the star has “ears.” I regularly use 25 X 100 mm binoculars, and the rings of Saturn are then clearly visible. Therefore, any scope you use from 25 power on up will allow you to see the rings of Saturn. Below are three views of Saturn that are likely for amateur telescopes. The smaller blurry image represents what you might see with a very inexpensive discount store telescope (best to avoid). The other two images represent views from Dobsonian reflectors ranging from 6 to 10 inches. The bottom line is if you own any telescope, you can see the rings of Saturn; wow!!

Naked Eye Sights: Observe the disappearance of the constellation Orion in the west throughout this month. All of our cold weather always leaves with Orion. Follow Saturn in the southeast and south throughout the month as it moves above Spica.

Binocular Sights (7 to 10 power): Continue your Messier hunt as discussed in last month’s column.

Telescope Sights (60-100mm): Check the return of Saturn and its rings in the southeast.


See you next month!