A Totally False Perspective of Mars and Moon

For those looking for planets in July, the morning hours before sunrise offer the treat of seeing the bright planets of Jupiter and Venus.  Through steady binoculars or with a telescope, Venus has lost is earlier crescent shape as it heads further away where the sun illuminates more of the side facing earth.   Jupiter always puts on a good show with its four largest moons doing a nightly dance around the planet.   August will offer better viewing of Jupiter as it rises earlier in the evening along with the lengthening nights. 

With our longer summer days, July would be a good time to turn our attention to our closest celestial neighbor, the moon.  The beautiful crescent of a new moon in the western evening sky usually catches our attention while the full moon rising above the eastern horizon can at times take our breath away.  The full moon on July 7 offers enough light for a country stroll or romantic evening on the beach watching the shimmering water and a distant shoreline.  A full moon occurs when the moon is on the opposite side of the earth from the sun where we can see the fully illuminated side of the moon.  This becomes obvious as you stand in an open area and see the moon and sun in opposite directions. 

After July 7, you may notice the moon rising later and later each night and waning in size each evening.   Within a week, the moon doesn’t rise until after midnight and by the weekend of July 18, a smaller crescent moon rises in the morning skies shortly before dawn.  During these two weeks, the moon has made a half orbit around the earth and is approaching a position between the sun and the earth.  This July, the angle of the moon’s orbit takes it directly between the earth and sun, producing a total solar eclipse.  The shadow of the moon will fall on parts of Asia and the South Pacific producing the longest solar eclipse of the century.  A total solar eclipse is one of nature’s most fascinating phenomena and you should plan to see one of these at least once in your lifetime.  Total solar eclipses occur almost every year but often in fairly remote locations.   In August 2017 a total solar eclipse will cross much of the USA and should be accessible to any who can travel within North America.
During the period from full moon until new moon when the illuminated side of the moon grows smaller each night, we describe the moon as “waning.”  From new moon until full moon the illuminated side of the moon grows in size each evening and is described as “waxing.”  Usually we cannot see the moon within 24 hours before or after it becomes “new” because of its proximity to the sun.  You may also notice that the dark side of the new moon is slightly illuminated.  This is sunlight reflected off earth’s oceans and clouds back to the moon and is called “earthshine.” 

Finally, if you are examining the moons craters and mountains with binoculars or telescope, you will notice that the moons features are most obvious near the line between light and darkness.  Along this line, called the “terminator,” shadows created by the angle of the sun offer a depth perspective on the moonscape.   We wish you clear skies for your summertime viewing of our night skies.