For those with an ‘astrological‘ leaning, the Sun will be passing from the constellation of Cancer to Leo on August 11th, where it will remain for the remainder of the month. However, since the Sun is not visible at night and we cannot observe its zodiacal migration, we will instead explore the celestial sights of August starting with the Moon.
The Moon will be at its closest approach to earth on the 2nd and again on the 30th, and at its furthest remove from Earth (apogee) on August 18th. Other notable dates relating to the moon are listed below for observers in the northern hemisphere:
Full moon July 31, 2015
Last quarter August 6, 2015
New moon August 14, 2015
First quarter August 22, 2015
Full moon August 29, 2015
During August, it is sometimes possible to see the phenomenon known as “Earthshine” on the 15th to the 19th, and again on the 8th to the 12th, which is light reflecting off Earth onto the night side of the crescent moon. The moon during August is also known as the “Full Sturgeon Moon” among some Native American people because of the ease with which the great sturgeon fish of Champlain, and the Great Lakes, are caught at this time of year.
The Perseids, the most popular meteor shower of the year, will be at its best before dawn on August 13th when you can expect to see a peak of between 70 and 80 meteors per hour, although they will be visible for most of August, albeit in fewer numbers. Their radiant point is the far northern constellation of Perseus, next-door to Cassiopeia, but throughout the night can appear all across the sky.
Also known as the “tears of St. Lawrence”, the Perseids are the result of the debris left behind by the comet Swift-Tuttle, which in August of the year 2126 is expected to pass at an estimated distance of only 14.2 million miles ( 22.9 million km) from Earth. Nonetheless, the Perseids are expected to be exceptional this year since there will be no moon light. New Moon is on the 14th.
Mercury will be visible low on the horizon for about an hour during twilight, but never sets later than 55 minutes after the Sun for the whole of August.
On the 15th, Venus passes between the Sun and Earth, and will thus not be visible as the Evening star after that date. During the second half of August, Venus becomes visible as the Morning Star low on the eastern horizon just before sunrise. Around the 31st, when the planet rises two hours or so before sunrise, firmly held binoculars will reveal Venus as a small crescent, much like a waning crescent moon just before a New Moon.
During August, Mars becomes visible as a morning twilight object as it moves out of the Sun’s glare. During the month Mars also moves into conjunction with Venus, although at their closest approach, they will be around 9 degrees apart. Look for Mars with binoculars during the last days of the month, low on the horizon in the northeast anytime from around 0300 in the morning twilight.
Being in conjunction with the Sun, Jupiter will not be visible for the whole of August.
Although Saturn sets rather late, around 2300 in the beginning of August, it is located in Libra, which makes it a challenging target due to its proximity to the horizon, and the persistent heat haze during late summer. However, a modest telescope may reveal the “top”, or northern surface of the ring system when the planet is at about 5 degrees from the horizon in the south-west during the first few days of the month, but be prepared for less than perfect seeing conditions.
Located in Pisces, Uranus rises from around 2200 in the first days of August, and remains visible through the night until the morning twilight becomes too bright. Being at the limit of naked-eye visibility, Uranus forms an attractive, albeit sometimes difficult to spot triangle with the stars zeta, and 88 Piscium.
In theory, Neptune should be visible with small telescopes as it moves toward opposition during the last days of August, leading into early September. Look for Neptune at about midnight, when it culminates roughly 3 degrees to the upper leftward of the star sigma Aquarii. The brightest object at that location will be Neptune, as there are no other luminous stars in the immediate vicinity.