Mars Mania 2018: Before the Dust Storm

August 2018  :  Dave Huestis

This article was written in May 2018 as an observing guide in anticipation of Mars’ close approach on July 31, 2018. Unfortunately a dust storm began on May 30 that eventually encircled the planet and enshrouded it, preventing surface detail from being observed. A revised Mars observing Guide, titled Mars 2018: Dust Storm Aftermath, was substituted.

Amateur astronomers have been anxiously awaiting the closest approach of Mars to the Earth since 2003. On July 31 the Earth-Mars distance will be only 35,785,537 miles. The two planetary neighbors won’t be this close again until 2035, so I’m sure the news media will be hyping the event. It’s been over two years since I’ve written about Mars. Why? As it is with most things astronomical, events in our solar system occur in a cyclic manner. Earth and Mars have a close encounter every 26 months. During the last few months the Earth has been catching up to Mars in our respective orbits, since the Earth orbits the Sun (one year) in less time than Mars does (1.88 years). So the Earth effectively laps Mars. Unfortunately not all Mars’ close encounters are favorable ones. That fact is due to the eccentricity of Mars’ elliptical orbit and its distance from the Sun. However, this year’s close encounter is going to be splendid!

For this article I am not going to recount the history of Mars observations or spacecraft explorations other than to say the initial accounts of possible “canals” on Mars at the end of the 19^th century captured our imagination and most assuredly hastened our spacecraft exploration of this desolate world. If you would like some historical background, visit this link on the Skyscrapers web site: http://www.theskyscrapers.org/mars-past-present-and-future.

When I’m able to show a young child a great view of Mars through Seagrave Observatory’s 8-inch Alvan Clark refractor telescope or Ladd Observatory’s 12-inch Brashear refractor, I often wonder if that young person may be the first human to set foot upon Mars’ alien landscape. This explorer will be able to step up to a rock outcropping and pick away at the formation hoping to discover evidence of past life. (Much like I imagined doing as I watched the fantastic images transmitted to Earth from the Mars rovers.)

This brief Mars observing guide will help you to discern and appreciate the planetary detail a telescope may show you of this neighboring world. Considering how close our two worlds will be, even a small 2.4 inch refractor should show some surface features, including the South Polar Cap and a few dark markings. And if seeing conditions are perfect, one should be able to “crank up” the magnification to coax additional detail out of the image. Larger aperture telescopes will reveal increasing detail.

You can begin to observe Mars as soon as you read this article. Due to a variety of publication dates, you may have missed the close approach (July 31), but believe me the view of Mars will still be marvelous. Be sure to check out the free public observing sessions at the local observatories. Plans are being developed for special Mars observing programs. You can use what you learn here to enhance that experience, or better still, to explore Mars with your own telescope.

Mars will not be hard to locate in the sky. On the night of closest approach Mars will rise above the southeast horizon after sunset. You can’t miss its distinct bright pumpkin-orange color. You should wait for it to climb higher into the sky and out of any horizon haze and turbulence. By 10:00 pm Mars will be almost 14 degrees above the horizon and awaiting your scrutiny among the stars of the constellation Capricornus. Later in August it moves into neighboring Sagittarius for a couple of weeks before moving back across the border into Capricornus once again.

Once you focus in on Mars with a telescope, closer inspection will reveal the surface color to be more peach-like. The second detail that should catch your eye will be the South Polar Cap (SPC). It’s a fairly bright white feature that can be easily seen because Mars’ south pole is currently tilted 11 degrees towards the Earth.

Spring began in Mars’ southern hemisphere on May 22, so the SPC has had some time to melt. Mars’ southern hemisphere summer doesn’t occur until October 16, so as time passes an observer should be able to notice the SPC shrinking and breaking up. Despite Mars closeness to the Earth this year, the planet can still appear to be fairly small. Wait for steady seeing conditions to observe as much detail as possible. The SPC will continue to shrink as the Martian summer progresses, while the Earth/Mars distance will be increasing and the image size will be decreasing as the Earth pulls out ahead of Mars in our respective orbits.

(While the North Polar Cap is tilted away from the Earth, you may see hints of the North Polar Hood, bright clouds around the north polar cap.)

While the SPC should be rather apparent, the rest of Mars will appear as a peach-colored “beach ball”. As you more carefully scan the planet you should begin to notice several dark surface features. These markings are the underlying rock exposed by the shifting sands during intense dust storms. The amount of detail seen will depend upon the size of your telescope and its magnification. However, atmospheric conditions above your observing location will be the definitive limiting factor.

One should easily observe a dark feature like Syrtis Major, once thought to be a plain, but now recognized as a low profile shield volcano. It looks similar to the Earth’s Indian subcontinent. In addition, Hellas Basin, a bright feature which lies between Syrtis Major and the SPC, is a large meteor impact basin about 1,400 miles in diameter and about 4.5 miles deep.

Remember, you don’t have to know the names of the features you glimpse. Just simply enjoy the view of any surface feature you can observe. However, if you wish to identify some of Mars’ dark and bright surface features you can use a utility called Mars Profiler provided online by Sky and Telescope magazine (http://www.skyandtelescope.com/observing/interactive-sky-watching-tools/mars-which-side-is-visible/). The Mars Profiler app opens with south at the top. You can toggle the tabs to set the app to the view your telescope provides. You’ll need to know if your telescope optics present Mars with south at the top or bottom of the image. Left or right orientation is less crucial for identifying features.

Also please keep in mind that Mars rotates once in 24 hours and 38 minutes. That means if you observe a feature at a specific location at a specific time on a given night, you’ll have to wait an additional 38 minutes each successive night for it to be at the same spot, since the Earth rotates once every 24 hours.

Mars is also noted for producing dust storms that can globally enshroud the planet. When this occurs the dust can prevent any of its surface features from being observed. These storms are active when Mars is at perihelion (closest to the Sun), and that is now. Also, they are most prevalent in the southern hemisphere (also facing us now) and as summer in that hemisphere begins on October 16. So if you start to lose detail on the Martian surface look on the web to see if a dust storm is in progress. (While I was writing this column during mid-June, a large dust storm was intensifying on Mars. If it becomes one of global proportions, our view of any surface features may be compromised.)

In conclusion, be patient when observing Mars. The planet’s disk will still be fairly small. Wait for steady seeing conditions. Don’t try observing Mars if the stars are twinkling. Twinkle twinkle little star may be a nice child’s poem, but if the stars are twinkling that indicates atmospheric turbulence. You’d be better off watching the movie The Martian. Be patient while observing Mars. (Note: Contributing to bad seeing is the fact that Mars will traverse a low arc across our southern New England skies during this close encounter.)

Drag out those telescopes from the basement, attic or garage and treat yourself and your children to the best views of Mars we’ll experience until 2035. One day they or your grandchildren may set foot upon this exciting landscape. Take a knowledgeable glimpse of an alien world that inspired generations of astronomers and science fiction writers alike to ponder the existence of Martian life-forms.

If you do not own a telescope you should make every effort to visit the observatories throughout Rhode Island to experience the best views of Mars. Seagrave Memorial Observatory in North Scituate (http://www.theskyscrapers.org) is open every clear Saturday night for observing. Ladd Observatory (http://www.brown.edu/Departments/Physics/Ladd/) in Providence is scheduled to reopen Tuesday, July 10, and every clear Tuesday thereafter. The Margaret M. Jacoby Observatory at the CCRI Knight Campus in Warwick (http://www.ccri.edu/physics/observatory.htm) is open every clear Thursday night. Also consider visiting Frosty Drew Observatory (http://www.frostydrew.org/) in Charlestown on every clear Friday night. Please visit the respective websites for details. These observing sessions are free and open to the public.

Become a part of Mars mania.