Observing a Fascinating Full Moon Using Mobile Apps: Part 2 — Supermoon

This weekend’s full moon, traditionally famous as a Oak Moon, Cold Moon, Long Nights Moon and a Moon before Yule, occurs reduction than one day before perigee, a indicate in a moon’s circuit when it is closest to Earth — creation this full moon a largest and brightest supermoon for 2017. With a moon 7 percent incomparable than average, there’s no improved time to take a closer demeanour during a moon. 

In Part 1 of Full Moon Mobile Astronomy, we discussed regulating unaided eyes and binoculars to see a large-scale aspect geology of a moon. In Part II, we’ll cover what to demeanour during with your telescope, and offer some tips for creation a many of watching a full moon. We’ll prominence a best mobile apps for anticipating lunar features. And if we suffer pity your unrestrained for astronomy with propagandize groups or during open star parties, we’ll advise some fun full moon activities that will make it value your while to set adult your telescope during that prejudiced of a monthly lunar cycle. [Supermoon 2017 Guide: When to See December’s Cold Moon]

Supermoons can seem 30 percent brighter and adult to 14 percent incomparable than standard full moons. a href=http://www.space.com/11161-supermoon-full-moon-science-infographic.htmlLearn what creates a vast full moon a loyal 'supermoon' in this Space.com infographic/a.
Credit: Karl Tate/SPACE.com

As we lonesome in Part 1, a sun’s light shines plumb downward onto a lunar aspect during full moons, so no shadows are being expel by a moon’s topography. Instead, all a variations in liughtness are caused by differences in albedo, a volume of intent being reflected off a several stone forms and textures. 

The moon’s splendid regions are heavily cratered highlands stoical generally of a fine-grained and low-density stone called anorthosite. The dim areas on a moon are stoical of a dense, iron-rich, coarse-grained stone called basalt. Several billion years ago, some event, presumably a vast impact on a moon’s distant side, caused a dim basalts to upsurge ceiling and out, covering vast areas of low-lying anorthosite and formulating a prosaic “seas,” or maria, that we see today. The maria basalts are about 0.62 to 2.5 miles (1 to 4 kilometers) thick.

Since a maria formed, objects have continued to torpedo a moon’s surface. Planetary scientists can review a story of a moon (and other solar complement worlds) by observant how new craters, and a element they eject, overwrite existent craters and other landforms. Bright waste from impacts into a highlands gets widespread over a dim maria as rays of ejecta, manifest explanation that they happened after a basalts were emplaced. Conversely, impacts into a basalts can widespread dim rays onto a highlands. And some impacts have been enterprising adequate to punch by a basalt, exposing and swelling a buried anorthosite.

These albedo differences, including bright- and dark-floored craters, craters with splendid or dim haloes, and ray systems, are many apparent during a full moon periods. Many facilities are best noticed by a telescope — any stretch will do. Below, we’ll prominence some of sold interest.

When indicating out particular facilities on a moon, it’s critical to remember that observers in Earth’s Southern Hemisphere see a moon flipped upside-down. So rather than demonstrate locations regulating tip and bottom, and left and right, it’s improved to use a concept complement of north, south, easterly and west. But there’s a turn that’s singular to a moon. We’ll demeanour during that next. 



Just as Earth has a tangible coordinate complement to map locations on a surface, so do all of a vital bodies in a solar system, including a moon. We use a pivot of revolution to conclude a poles and afterwards conclude an equator by sketch an hypothetical line, during right angles to that axis, around a core of a object. For someone looking from Earth’s northern hemisphere, north on a moon is up, and a series of degrees north or south of a moon’s equator denotes a feature’s selenographic latitude.

For longitudes, we name a indicate somewhere on a equator and pull a line from stick to stick that runs by it. This defines a 0 degree, or central, meridian. On Earth, a Central Meridian was arbitrarily selected to pass by Greenwich, U.K. All longitudes on Earth are totalled in degrees easterly and west of that meridian. For a moon’s selenographic coordinates, a executive apex runs by a indicate on a moon’s equator that, on average, points toward a core of Earth. (We have to use an normal since a moon wobbles.) 

As on Earth, selenographic longitude is totalled in degrees from a executive meridian. By definition, easterly on a world or moon is a instruction toward morning — though this creates a bit of difficulty for Earth-bound moon watchers. For an spectator on Earth, morning on a moon, that occurs while a moon is waxing in a days after a new moon, happens on a observer’s western side. For someone station in a Northern Hemisphere on Earth, easterly on a moon will be to a viewer’s right, while easterly on Earth will be to a viewer’s left. A void located in a southwest segment of a moon’s hoop will therefore be to a viewer’s revoke left. To state it simply, easterly and west are substituted when looking during a moon from Earth.

The start indicate for a moon's selenographic coordinate complement (where a dual red lines intersect) uses a moon's equator and a plcae on it that points toward Earth's center. East on a moon is toward a right for observers in a Northern Hemisphere. To see this plcae in your telescope, demeanour for a little craters Bruce and Blagg and bound southward by their separation. The Surveyor booster alighting sites are nearby.
Credit: SkySafari App

The best apps for assisting we find specific facilities on a moon are SkySafari 5 Plus (or Pro) for Android and iOS and LunarMap HD for Android. Both apps arrangement labels and yield additional information, such as stretch and a start of a name. The giveaway LunarMap Lite app omits smaller features, though will work customarily as good for a purposes. Apple users can also check out Moon Globe HD app and a giveaway Moon Globe Lite version. 

By default, a underline labels are infirm in SkySafari 5. Look in a app’s Solar System Settings menu for a choice to switch them on. The LunarMap HD app allows we to adjust how many labels are being displayed — regulating a intent size, or a intent type, as a cutoff. Both apps concede we to hunt for facilities by name.

While binoculars do not, many telescopes mirror-image and/or flip what we see. In SkySafari 5, drumming a tip right dilemma of a arrangement opens a pop-up box with Flip settings — None, Horizontal (i.e., left-right), Vertical (i.e., up-down) and Both. It’s a good suspicion to find out what your telescope does and name a choice that matches it. (Remember to return to no flipping when we are finished.) The same options for a LunarMap HD app are in a Observing Equipment setting.

The moon is a monumental steer underneath magnification, generally regulating a backyard telescope. A low energy eyepiece that fills a margin of perspective with a whole moon is a ideal approach to start your full moon observing. This will easily uncover a differences in albedo. Note that some maria are darker than others. For example, Oceanus Procellarum (Ocean of Storms) and Mare Imbrium (Sea of Showers), both situated toward a western (left-hand) segment of a moon, are lighter gray than a maria on a moon’s eastern (right-hand) side. Other maria have disproportionate shades of gray. Mare Serenitatis (Sea of Serenity) is darker along a southern corner since a basalts are of a opposite age and composition.

In a telescope, a full moon will be roughly painfully bright, generally in incomparable orifice telescopes. To lessen this, see if your telescope’s lens tip has a secondary, smaller opening and perspective a moon by that (effectively shortening your telescope’s aperture). Alternatively, we can squeeze a neutral firmness filter that attaches to your star erratic or eyepiece, slicing some of a light reaching your eye. For a bit some-more money, a non-static polarizing filter lets we invariably adjust a volume of light it passes. That form of filter is also useful for obscure a glisten from splendid planets, thereby enhancing their aspect features. [Best Telescopes for a Money – 2017 Reviews and Guide]

The impassioned liughtness of a full moon can make watching it by a telescope uncomfortable. Stopping down a aperture, or adding neutral firmness or non-static polarizing filters, are effective ways to conduct a light.
Credit: Gregory H. Revera/Wikimedia Commons/Orion Telescopes/ Carson Optical

Now, let’s wizz in on a few specific treats that are manifest during full moons. There’s no need to use too high a energy of magnification — about 100x to 150x is plenty. This will vaunt facilities as little as about 2 miles (a few kilometers) across. We lonesome Copernicus and a endless ray complement in Part 1. Focusing your telescope on Copernicus will vaunt round patterns around a inside of a crater’s rim. These are terraces where slumping has occurred. Scanning divided from a crater, we can follow some of a incomparable ejecta rays.

There are indeed many manifest ray systems on a full moon. With little to no topographic relief, they are not extended by inclined intent during a prejudiced phases of a moon a approach towering facilities are. The huge complement around a void Tycho extends for during slightest 950 miles (1,500 km). The impact occurred customarily about 108 million years ago — customarily yesterday in geological time. During full moons, Tycho’s void building is intensely bright, too. 


Under full-moon illumination, a vast void Copernicus (upper right) displays an huge ray complement that has widespread splendid ejecta over a dim basalts of Oceanus Procellarum. The slumped terraces around a crater's corner (inset) mount out, too. A brief stretch divided from Copernicus, dual little impactors after penetrated a ray element and dug adult a underlying dim basalt, producing dim haloes around themselves. They can be seen as dim spots to a tip left and revoke right of Copernicus. Several other little craters mount out brightly since their void floors are a unprotected white rocks of a lunar highlands that underlay Oceanus Procellarum.


Here are a few some-more ray systems to demeanour for in a telescope; any is named for a void that constructed it. Use a hunt underline in your app to uncover we where they are on a moon’s disk. I’ve remarkable some additional elements to demeanour for. You can also customarily indicate around a moon looking for rays and afterwards use a app to establish their name.

The void Proclus facilities an uneven ray complement constructed when a crater’s impactor arrived during a shoal angle, blustering element customarily toward a northeast, including circuitously Mare Crisium (Sea of Crises). The void Dionysus has both dim rays and a splendid halo constructed by a multiple of low and shoal excavation. It’s a customarily instance of this materialisation on a nearby side of a moon. Kepler, located customarily west of Copernicus, is a little and new void with a vast ray system. The adjacent craters Autolycus and Aristillus vaunt splendid rays during a full moon and darker ejecta blankets during a quarter- moon phases.

During a full moon, discolorations demonstrative of localized geological differences are also enhanced. The little void Censorinus, located on a corner of Mare Tranquillitatus (Sea of Tranquility), and not distant from a Apollo 11 alighting site, is one of a brightest spots on a whole full moon. Inside a vast void of Deslandres is a little sequence of craters, including one with a really splendid building and an uneven ray complement fluctuating eastward. It’s so little and splendid that it competence remind we of a star. To assistance we locate it, it’s customarily to a easterly of a incomparable void named Hell. The Italian astronomer Cassini claims to have seen a splendid white cloud in a area, so it’s nicknamed Cassini’s Bright Spot.

Left panel: The heated splendid mark during a tip right is Cassini's Bright Spot, a underline so distinguished that some people can see it with unaided eyes. The round void to a left is named Hell. The vast void nearby a bottom is Tycho. The dim void during tip left is Pitatus. Right panel: This combination picture of a void Atlas, taken in 1967 by a Lunar Orbiter 4 spacecraft, shows dual dim rags inside a crater, toward a tip and to a revoke right. Most apparent during full moons, a spots are suspicion to be pyroclastic charcoal deposited by volcanic eruptions after a void was formed.
Credit: NASA/Wikimedia Commons and Peter Lloyd, used with accede

Embedded within Copernicus’ ray complement are dual little craters that have dim halos constructed when little bodies after struck a moon and excavated a maria basalt. Copernicus H lies to a southeast and Gay-Lussac N is to a north. (Uppercase minute suffixes are used to brand delegate craters that approximate a primary one.)

The void Atlas exhibits dual dim spots that are substantially pyroclastic charcoal deposited by volcanism after a void was formed. And while we are in a area, demeanour inside a adjacent crater, Hercules, for a little splendid crater, Hercules G.

As a final treat, aim your telescope toward a segment around a void Aristarchus, inside Oceanus Procellarum. The void has a really splendid building and an uneven ray system, though it sits within one of a many colorful regions of a moon. During full moons, we competence notice tints of brownish-red or orange north of a crater. Orbiting probes have rescued sulphur compounds and hot radon-222 emissions in a area. [Giant Moon Crater Revealed in Up-Close Photos]

Taking smartphone cinema of a moon by a telescope is intensely easy, and guest will have a commemoration of a evening. With a moon centered and focused in a eyepiece of a telescope, kindly rest a device’s camera opposite a rubber eye guard. (Doing this helps revoke a effects of unsure hands, and prevents any wandering light from reaching a camera.) With a camera app running, use little movements behind and onward to find a moon. When it is centered on a screen, daub a arrangement to concentration a picture and click a shiver button. If we can’t seem to reason it solid adequate while triggering a shutter, try enabling a shiver check to give we a few seconds to settle your movements. Most camera apps concede we to adjust a exposure, customarily with a slider. This will assistance to keep detail.


Credit: Tanya Oleksuik, used with accede


Using higher-power eyepieces will let we take close-up cinema of a particular facilities we’ve mentioned above. Some telescope owners have invested in smartphone brackets that can reason a smartphone in place. The brackets are also a good approach for a organisation of observers to see what a telescope is focused on.

We’ve customarily scratched a lunar surface. There’s copiousness some-more to see on a moon. It’s not required to wait for a night of a full moon to observe a singular facilities we’ve covered. For a day or dual on possibly side of full, a sun’s light will be resplendent scarcely true down on a areas that are good divided from a terminator (the line that divides a illuminated and dark sides of a moon). In a destiny book of Mobile Astronomy, I’ll prominence some-more of them. In a meantime, keep looking up!

Editor’s note: Chris Vaughan is an astronomy open overdo and preparation dilettante during AstroGeo, a member of a Royal Astronomical Society of Canada, and an user of a ancestral 74″ (1.88-meter) David Dunlap Observatory telescope. You can strech him around email, and follow him on Twitter @astrogeoguy, as good as on Facebook and Tumblr.

This essay was supposing by Simulation Curriculum, a personality in space scholarship curriculum solutions and a makers of a SkySafari app for Android and iOS. Follow SkySafari on Twitter @SkySafariAstro. Follow us @Spacedotcom, Facebook and Google+. Original essay on Space.com.