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Wednesday, April 1, 2015

Look At The Sky: April




THE APRIL 4 TOTAL ECLIPSE OF THE MOON

A very special treat is in store for stargazers in the western USA as well as most of the south Pacific, Australia, etc.  The full moon on April 4 will undergo over 9 hours in various stages of eclipse by the earth's shadow.  Those living WEST of Arkansas Sky Observatory will be able to view the eclipse all the way into totality, but for ASO and points east, the moon will be setting just as totality begins on the morning of April 4.  For full details and a map of the path of the earth's shadow, see the NASA site:


The Solar System in April 2015
An excellent month for planetary viewing, with Jupiter and Saturn ruling the skies!

Mercury - Although VERY close to the sun and in strong twilight in April, watch for Mercury to climb into the western sky a bit higher each night after April 20; from the 21-24, watch as tiny bright Mercury moves eastward past the ruddy red planet MARS - in ARIES

Venus - Very bright and high in western April skies this 2015, in the constellation of Taurus.  This is a very favorable time to view Venus, with its disk about 75% illuminated as we see it from Earth and at magnitude -4.1 brighter than any object in the sky except for the sun and moon! - in TAURUS.

Jupiter -  Our mightiest of planets, Jupiter, will be directly overhead at dark this month, a very dominating yellow orb straight up for northern observers; although the planet is a bit farther from us than last month, it is still a wonderful telescopic object. .  - In CANCER

Saturn -  The ringed planet will be rising at about 11 p.m. local time and will dominate the skies this month and through the summer.   This remarkable planet is very favorably placed with the rings tilted favorably toward earth this month  - in LIBRA


APRIL METEOR SHOWERS:

Observe when the moon does not interfere and attempt to observe AFTER midnight for most meteors to be seen!  For April, there are no less than NINE meteor showers, some of which provide for wonderful spring sky shows, provided that the light of the moon does not interfere.  However, as with a months and times during the year, observers should always be aware that new sporadic meteor showers can occur at anytime from seemingly unknown sources and radiants.  NOTE:  one of the most interesting of all meteor showers is the odd "April Fireballs" (see below) which occur this month.

April 4 - Kappa Serpentid Meteors - This is a one-week-duration meteor shower, from April 1 through 7, with somewhat of a mild peak about midway through that period; look for the radiant to rise in the constellation of Serpens about 8 p.m local time just south of due east and be nearly overhead for observers in southern latitudes of the northern hemisphere at about 2 a.m.  Several meteors per hour should be seen from this minor radiant in normal years, and this year is poor since the moon will be full at this peak and dominate the sky all night long

April 7 - Delta Draconid Meteors - With no particular peak to speak of, this is one of those "circumpolar" meteor showers for northern hemisphere observers that will be in the sky pretty much all night; it is a very long duration shower from late March until about April 17.  Found only in 1971 in the constellation of Draco, the meteors are conspicuously slow and leave very fine trains in their wakes; to view the most meteors from this now-annual shower, set up about 10 p.m. local time and face somewhat northeast; as the night progresses the meteors will be originating more and more from very high northern skies....thus after midnight direct your sights to nearly directly overhead, the ZENITH.  Note that the moon, slightly less than full and very bright before midnight will hamper observations during the course of the night

April 10 -Viginid Meteors - This is the first of THREE meteor showers which appear to emanate from the constellation of VIRGO during the month of April each year.  A two-week display, the meteors can be seen coming from just south of overhead (northern hemisphere) from April 1 through 15 with no definite peak; to differentiate THIS shower from the other two, the radiant is centered at near right ascension 12h 24m / declination 00 degrees.  This year the moon is strongly gibbous and its light will interfere until just before dawn, so this will be an unfavorable year for this meteor shower..

April 14 - THE APRIL FIREBALLS - A particularly good year for this interesting shower in early morning hours because the thin crescent moon will be rising well after midnight and should not hamper observations on this date!....., but then again being bright fireballs, these can be seen in spite of even city lights!   As its name suggests, this can sometimes be a pretty spectacular display if the conditions are right and the skies are dark; however, during times of the new moon - as it was in 2010 - , these huge and bright fireballs come streaking clearly across our crisp and clear springtime skies along with countless fainter meteors that are associated with no identified meteor swarm.  This unusual display lasts for the last two full weeks of April....there is no known radiant or seeming point of origin for this curious group, and they can be seen originating from just about any part of the dark night sky.  They likewise are not - or appear to not be - associated with any other known major or minor meteor shower group.  The April Fireballs are characterized by tremendously bright meteors, nearly all of which demonstrate beautiful and long-lasting trails through the sky.   Even with the bright moon however, with their brightness, the light should not interfere for observing these very spectacular meteors.  Always look for the April Fireballs late in the night, preferably after midnight.   Because of the late nature of the peak of these unusual meteors, 2015 should be a  favorable time to try to catch a few of these.  NOTE:  several of these renegade meteors have been known to reach the ground as meteorites!  Heads UP!

April 17 - Sigma Leonid Meteors - The Sigma Leonids are no longer "in" Leo....they have migrated it seems into Virgo to become one of our three Virgo showers for April.  The radiant is up early, just due south of overhead about 9:30 p.m. local time; this is a minor shower with only a few members seen on dark nights per hour.  The nearly new moon will be absent from the sky all night  so it should not interfere with observations of this shower

April 22 - The Lyrid Meteor Shower - Other than some spectacular fireworks from the April Fireballs (see above), this is April's most dependable meteor showers and typically one of the best of each year; this year the first quarter moon will not interfere with any observing of meteors meteors after midnight, typically the best time to view the greatest number of Lyrids.  This shower is comprised of cometary debris from Comet Thatcher, a very famous comet last seen in 1861.  Although this associated comet was not identified until only 100 or so years ago, this meteor shower from it's demise is one of the oldest known on record, being recorded by the ancient Chinese stargazers first in 687 B.C.  As with many meteor showers - and the comets they come from - this one seems to be waning with every encounter with the earth however.  It is no longer the sky spectacle as recorded by those earliest sky watchers.  Look for the meteors to emanate from a point on the Hercules-Lyra border, very near the brilliant blue-white star Vega.  The radiant rises about 7:30 p.m. local time, but the best time to see the most meteors each year is always around midnight when the radiant is nearly directly overhead at midnight for northern hemisphere observers.

April 25 Mu Virginid Meteors - This is our third of three meteor showers within the constellation of Virgo for the month of April, and is south of overhead about 1 a.m. local time, far in the eastern realms of the large Virgo constellation; it takes dark, moonless skies to see the few  - only about 7 per hour - meteors from this annual minor display.  The quarter moon will set shortly after midnight, so you might wait until late for this one!

April 23 - Grigg-Skjellerup Meteors - Here is an oddity just by its name...the only annual meteor shower known by the comet from which the meteoroid cloud came!  It also is unique in that it is a "localized" meteor shower, visible only in certain parts of the world, but not others, on each pass.  For example, there was a brilliant display of these meteors seen in New Zealand in 1977....but not one in the United States.  If visible, they will be seen early in the evening, originating south of overhead.  At right ascension 07h 48m / declination -45 degrees, these will appear to be coming literally from the south horizon for northern hemisphere observers, perhaps the only way to differentiate them from the other meteors showers in the same direction of sky each April.  This year is a poor year for this unusual meteor shower since the quarter moon will dominate the early evening period in which this shower should be seen.

April 28 - Alpha Bootid Meteors - Coming from a point very near the bright "alpha star" Capella in the constellation of Bootes, this radiant is in the sky from dusk until dawn, and nearly overhead at about 1 a.m.  Look for these meteors to be few, BUT those that are seen are typically very fine fireballs moving slowly across the sky and leaving beautiful "smoky trails" behind them.  Observers will be hampered by moonlight for this shower in 2015 - the radiant rises about 3-4 hours after sunset, and the moon will be dominant in the sky for this meteor shower in 2015




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