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Saturday, August 1, 2015

Look At The Sky: August (Meteor Month!)




The Solar System in AUGUST 2015:  http://www.arksky.org/index.php?pid=256

Mercury - Now in evening skies throughout this month and will remain fairly steady in terms of elevation/altitude above the western horizon, but appearing to move southward as the month progresses - in LEO.

Venus -  Our brightest planet is not favorably placed this month and will be hidden by solar glare throughout the early and middle days of this month; it will move from the evening sky into the morning sky around August 20 and hence will become our "Morning Star" for many months to come throughout the remainder of 2015 - in CANCER

Mars - Mars is now low in northeastern skies at sunrise, rising about 5 a.m. local time in mid-month; the tiny (less than 4 arc seconds!) orb will be difficult to spot in morning dawn twilight but will rise earlier as the month progresses  - In GEMINI

Jupiter -  Now in conjunction with the sun and not viewable by eye nor telescope!   In LEO.

Saturn - With its magnificent ring system tilted almost their maximum for earth-viewing, Saturn is high overhead in evening dusk and is in dark skies by 9 p.m. local time; however, by that time the planet has progressed far into low southwest skies.  By month's end, Saturn will be very low in SW skies and more difficult to view .  - in LIBRA.


METEOR SHOWERS:  Observe when the moon does not interfere and attempt to observe AFTER midnight for most meteors to be seen!  August offers some of the best observing conditions for meteors....the skies are typically quite clear, the cooling night air suggests that fall nights await and fill you with observing inspiration, and August holds five wonderful showers, one of which is the "granddaddy" of all predictable and dependable meteor observing outings.

The 2015 Perseids:  An excellent year for this normally reliable shower.  The famous PERSEID Meteor Storm will pass across the Earth's orbit once again this year in early August, and this year is very favorable for meteors to be seen because there will be no moonlight throughout the night!   Some meteors may be seen during early hours of days other than actually on the date of peak.  The sighting of fainter members of this shower will be easy this year on peak day, but expect brighter ones to begin to streak across our skies even in the first week of August....if you can trace their origin back to the constellation of Perseus, then what you are seeing are indeed Perseid meteors.   As with most meteor showers, the later you stay up (...yawn...), the more meteors you likely will see, particularly this year with very dark skies if you can venture away from city lights.  Begin watching the evening of August 10, and continue until the early morning hours of August 14 for your reward.  I recommend observing WEST of overhead around midnight, although only the brightest meteors will  be seen from this famous shower throughout the evening and morning because of the strong moonlight.

However, do not wait for August 12-13....this is a long duration shower and meteors will be easily seen during the first week of the month when skies are not hampered by the moon, particularly before moonrise late in the morning hours.

In 1992 Comet Swift-Tuttle, the parent object that spawns the Perseid meteoroid cloud, shed a great amount of dust in its wake and now sets the stage for intense activity as the earth passes through that debris; this will be the second year that the Earth has passed directly through this possible debris cloud.

Note that Comet Swift-Tuttle's (P/1862) one-revolution trail from 1862 will pass inside the Earth’s orbit this year. At the time of Perseids (the annual meteor shower associated with this comet (evening hours, local time, of August 12).  If there were a closer approach of this comet to the earth, a spectacular meteor storm would be expected...but with these conditions and no prior such close approaches to compare to, it is uncertain what kind of a shower this will give for 2015, just as it was for 2009 when the predictions were higher than actually were meteors seen.  Because of similar conditions, but with the earth passing directly through the major debris pocket of the comet, perhaps the best meteor shower of history will occur with the Perseids at some time in the near future....but it will not be 2015.

This is a long duration shower, with many (as many as two dozen per hour) being seen from August 9 through the 20th; during the PEAK, expect to see at least 60 or more (perhaps double that number!) around 2 a.m., streaming from the constellation of Perseus, high in the northeastern sky.  Best views are afforded by positioning your feet to the EAST and facing directly overhead. 

AND YES....there ARE other meteor showers in August!

August 1 - Capricornid Meteors.  The moon will full in our skies on the date of this meteor shower,  so you should expect a less-than-sensational show from this one.  Wait until after twilight ends (about 1.5 hours after sunset) in the early evening to begin serious skywatching.   Remains of comet Honda-Mrkos-Padusakova, about 35 meteors per hour - MANY which are bright fireballs! - can be expected in the morning hours; nearly due south of overhead about midnight.
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August 6 - Southern Aquarid Meteors - look on the meridian, southern skies about 11 p.m. local time for only a few meteors, perhaps 7-8 per hour.  This is a curious shower, comprised of two peaks:  this one, and another on about August 21-23.  Note that meteors from this (these?) showers are not seen yearly and observations are badly needed to fill in the missing gaps about our knowledge of them.  Some years no meteors are seen, but since the late 1800's when this double shower was noted and later confirmed, there have been distinct radiants (the "northern" and "southern") seen throughout many years.  Observations of this shower are badly needed and this might be a wonderful year in terms of absence of moonlight (moon is last quarter and will rise after midnight)
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August 20 - Kappa Cygnid Meteors - This is a fair year  for these meteors to be seen to their fullest.  The first quarter moon, setting about midnight.,  will be absent from the sky after that time and will not interfere with sightings of these meteors.  Typically many of these meteors are seen along with Perseid meteors, leaving very fine trains of smoke in their wakes!  The Cygnid (and the Andromedids, below) will be nearly overhead by 2 a.m.


August 31 - Andromedid Meteors - there will be a nearly full moon during the peak of this shower, so chances of seeing a good display are poor. In 1885, 13,000 Andromedids were seen per hour, all fragments of a now-disentigrated BIELA's Comet.  Very unpredictable, this meteor shower needs observations during such excellent times as unexpectedly occured in 2005. The shower radiant will be nearly directly overhead for mid-northern latitudes about midnight.




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