Saturday, May 21, 2016

End of May / Start of June: Best View of Mars in a Decade!

View larger. | This image shows our neighbouring planet Mars, as it was observed shortly before opposition in 2016 by the NASA/ESA Hubble Space Telescope. Some prominent features of the planet are clearly visible: the ancient and inactive shield volcano Syrtis Major; the bright and oval Hellas Planitia basin; the heavily eroded Arabia Terra in the centre of the image; the dark features of Sinus Sabaeous and Sinus Meridiani along the equator; and the small southern polar cap. Image via NASA, ESA, Hubble Heritage Team, J. Bell, M. Wolff.
New photograph of the Planet Mars, taken by NASA's Hubble Space Telescope, on 2016 May 12,
just before the closest approach to Earth on May 30.
[Image Sources: NASA,  ESA, Hubble Heritage Team, J. Bell, M. Wolff]

By Glenn A. Walsh
Reporting for SpaceWatchtower

In what should be the best view in a decade during the last weeks of May and the first weeks of June, the Planet Mars will be bright and quite noticeable in the evening and early morning sky! This is the brightest Mars has appeared since the Martian opposition of 2005 November 7.

On Saturday night (May 21) after sunset, Mars will be extremely easy to find as it is passed by the smallest Full Moon of 2016 (and, a “Blue Moon” by one definition!). During the mid-evening after sunset, Mars can be found just to the right of the Full Moon as both planetary bodies are rising in the southeastern sky. While Mars is known as the red planet, a bright reddish-orange star, Antares (in the Constellation Scorpius the Scorpion), can also be seen below Mars. And, to the left of Antares, below the Moon, is another planet: the beautiful ringed-planet, Saturn.

In the early morning sky before sunrise, on Sunday morning (May 22), the configurations will be different. Now, Mars can be found below the Full Moon as both planetary objects are getting ready to set in the southwestern sky. Antares is to the left of Mars, while Saturn is above Antares and to the left of the Full Moon.

After May 22, over the next few weeks Mars will continue to be found rising in the southeast after sunset and setting in the southwest before sunrise.

As with all planets, the best time to view Mars and Saturn with a telescope is when they are highest in the sky—right now, that would be between 1:00 and 2:00 in the morning, local daylight saving time.

Known as the red planet, particularly during the weeks around the time of opposition, Mars does appear in the sky with a bright, easily seen orange-yellow tint. With a modest-size telescope, or even binoculars, the orange color is even more pronounced.

In a telescope, and with good seeing conditions, one might be able to see a few vague lines on the planet, and perhaps even a tiny white polar cap. Although the bright, white ice at the north polar region of Mars is currently shrinking, this polar region is now tilted 12 degrees toward the Earth

Due to Mars further distance from the Sun than the Earth, Mars closely approaches the Earth once every two years. The fourth planet from the Sun, at a distance from the Sun of 141.6 million miles / 227.88 kilometers, it takes Mars 686.971 days (1.88 Earth years) to make one revolution around the Sun. The next close approach of Mars, to Earth, will be in July of 2018.

During some of these close approaches, such as in 2016 and also in 2018, Mars comes closer than usual. Mars will be at its closest to the Earth on May 30 at 6:00 p.m. Eastern Daylight Saving Time (EDT) / 22:00 Coordinated Universal Time (UTC), at a distance of 46.78 million miles / 75.28 million kilometers.

This distance can also be expressed as 0.50 Astronomical Units (one Astronomical Unit, abbreviated a.u., is the average distance between the Earth and the Sun) or as 4.2 light-minutes (similar to a light-year, a light-minute is the distance it takes light to travel in one-minute's time). At this distance, the disk of Mars will have a relatively large appearance, measuring 18.4 to 18.6 arc-seconds in diameter.

At the time of closest approach, Mars, astronomically, will have an apparent visual magnitude of -2.1. This is just-about the brightest Mars can appear in Earth's sky, although Mars will appear a little brighter during the Summer of 2018. And, this is almost the same brightness as the bright Planet Jupiter (which now is just a bit brighter at an apparent visual magnitude of -2.2), which can now be seen fairly high in the southwestern sky, during the evening hours.

Although the closest approach is not until May 30, Mars reaches the point in its orbit called “opposition” on Sunday Morning (2016 May 22) at 7:00 a.m. EDT / 11:00 UTC. Opposition, the point in the orbit of an outer planet when the Earth is directly between that particular planet and the Sun, cannot occur for Mercury or Venus, the two planets closer to the Sun than the Earth. At the point of opposition, the planet is brightly visible in the Earth's sky, from approximately local sunset to local sunrise.

At this time, Saturn is also near its brightest, as Saturn will reach its own opposition on June 3 at 3:00 a.m. EDT / 7:00 UTC, when it will be at an apparent visual magnitude of 0.0. The Star Antares shines at an apparent visual magnitude of +0.96. Visual magnitudes of stars do not vary, as such magnitudes vary for planets in our Solar System.

At the moment of posting of this blog post (Saturday Afternoon, 2016 May 21 at 5:14 p.m. EDT / 21:14 UTC) the Moon reaches the Full Moon phase. This is the smallest visible Full Moon of 2016, due to a lunar apogee three days earlier. The lunar apogee for May, the point in the Moon's orbit where it is the farthest from Earth for the month, occurred Wednesday Evening, 2016 May 18 at 6:00 p.m. EDT / 22:00 UTC, at an Earth – Moon distance of 252,235 miles / 405,933 kilometers.

The May Full Moon is primarily known as the Flower Moon to Native Americans. Due to increasing fertility in mid-Spring, along with the end of hard frosts and warmer temperatures better attuned to the bearing of young and the raising of crops, in Earth's Northern Hemisphere the Full Moon of May is also known as the Mother's Moon, and the Corn-Planting Moon or just Planting Moon. And, as the second cross-quarter day of the year on May 1 called Beltaine, or better known as May Day, was the time when farmers in Medieval Europe would move their cows to the better Summer pastures, the Full Moon of May was also known as the Milk Moon.

As the Southern Hemisphere begins to enter their colder months, their Full Moon names for the month of May include Hunter's Moon, Beaver Moon, and Frost Moon.

And, this year, there is one more name for this particular Full Moon. May's Full Moon can also be called a “Blue Moon.” However, this is not the “common” Blue Moon, which in recent years has been defined as the second Full Moon in a calendar month (monthly Blue Moon). And, the Moon will not actually appear with any type of blue tint.

This month's Blue Moon designation uses an older, more traditional, definition: the third of four Full Moons to occur in a single calendar season (seasonal Blue Moon), the present season of Spring. Normally, each calendar season only has three Full Moons.

Following the 2016 May 21 seasonal Blue Moon, the next seasonal Blue Moon will occur on 2019 May 18. The next Blue Moon by the more common definition, monthly Blue Moon, will be on 2018 January 31.

                            Internet Links to Additional Information

More about Mars: Link >>>

News: Cornell University. "Ancient Tsunami Evidence on Mars Reveals Life Potential." 2016 May 19:
Link >>>

More about today's Blue Moon:
Link >>>

More about a Blue Moon: Link >>>

More about Saturn: Link >>>

More about Antares: Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
             2016 May 21.

                                                               Historic 10-inch Siderostat-type Refractor Telescope at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.
        2016: 75th Year of Pittsburgh's Buhl Planetarium Observatory
     Link >>>

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