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 February 26th. For February, your best viewing nights will be from February 17th to the 28th. The Star chart below is set for Florence, SC on February 15th at 9 pm. Note: A table of contents for earlier columns is located in the February 2016 column.
The Planet Uranus:
There are seven planets in the night sky that you can see with the naked eye or with simple binoculars. The naked eye planets are Mercury, Venus, Mars, Jupiter, and Saturn. The last two, Uranus and Neptune are visible through binoculars. Usually finding Uranus or Neptune requires star hopping and good star charts. The reason for the difficulty is that these two outer planets are not in a region of the sky near any prominent stars, which could be used as locators. In addition, when these planets are in such a region of the sky, they remain there for several years, because the orbital time of Uranus is 84 Earth years, and Neptune is 165 Earth years. Therefore, the best times to find these outer planets, is when one of the bright faster moving inner planets lines up with them. The first time I reported such an alignment for the planet Uranus in this column was in June 2010 when the planet Jupiter passed under Uranus early in the morning. The second alignment I reported in this column was on February 2012 when Venus was just to the right of Uranus in the early evening. Now after five years have passed, the planet Uranus is again lined up this month near an easily visible planet; Mars. The image below shows a close up view of Uranus.
The good news is that using amateur telescopes, you should be able to see this planet as a small disk, and with a deeper blue color. I have found Uranus to have a nice pure color blue whereas the much farther out Neptune has a dim dull blue color.
Uranus is the first planet discovered with a telescope in the late 1700’s. It is also the farthest planet that is visible to the naked eye. In order to see Uranus with the naked eye, you will need extremely dark skies. It is unlikely that such a dark area would be in this area of South Carolina, however, on special occasions, a rare weather event may result in very dark and transparent skies. If you can clearly see all seven stars of the Little Dipper, then you might see Uranus with the naked eye. If you are at a dark sky site where you can see stars inside the bowl of the Big Dipper, then you can definitely see Uranus with your naked eye.
We will assume that super dark skies will not be available to you this month, so get out your binoculars. Uranus will be an easy target with 7 X 50mm or 10 X 50mm binoculars. To locate Uranus you will look to the southwest sky after sunset. The only shortcoming viewing Uranus is that it will be low in the southwestern sky. Therefore you must find a viewing location without trees or city lights in the southwestern sky. Below is an image showing the planet lineup earlier this month.
At that time, it would be quite difficult to easily find Uranus through your scopes. However, as the month progresses, Mars will move closer to Uranus. Using 7 X 50mm binoculars, Uranus will begin being seen in the same field of view as Mars beginning on February 16th and ending March 7th. The closest line of sight approach of the two planets will occur early on the night of the 26th; see image below.
Note the large red circle is your field of view through 7 X 50mm binoculars, and the smaller circle is 10 X 50mm binoculars. Note: On the night before the 26th, Uranus will be slightly higher up, and on the night after the 26th, Uranus will be slightly below the position on the image shown.
Set up your viewing equipment by 7 pm. From 7:30 until 8:30, you should have a good view of Uranus. Beginning with your binoculars, you will be able to record that you have seen the seventh planet from the Sun, Uranus. Moving on to your telescopes, you should be able see the blue color of this planet. If you have a Dobsonian telescope, you should be able to see Uranus as a blue planetary disk. The image below approximates the view through a good amateur Dobsonian telescope.
Note: To understand the immense distance you are witnessing, it took over two and a half hours for the light of Uranus to reach your eyes, while Mars, to the right of Uranus, took less than thirteen minutes for its light to reach you.
Naked Eye Sights: For those who have access to a very dark sky site, try to see Uranus just to the left of Mars on the night of the 26th. Enjoy the sights of the winter sky; such as the Orion constellation and the Pleiades.
Binocular Sights (7 to 10 power): Locate Uranus using only your binoculars. The Orion Nebula, the Pleiades, the Double Cluster and the open star clusters in Auriga and Gemini.
Telescope Sights (60-100mm): Try to resolve the blue color of Uranus. As always start at the lowest possible power of your telescope and then move set up to higher powers.
Dobsonian telescope (6 -8 inch): You should easily see the planet Uranus as a pretty blue disk.
See you next month!