Whats Up, Ron? is a monthly almanac for Northern American astronomersastras

WHAT'S UP?

by Ronald A. Leeseberg, the Star Geezer

July 2010 - Vol. 14 No. 6

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Features: Calendar | Lunar Almanac | Monthly Topic

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

Angular Measurement Review: It is interesting to note that the relationship between the angle subtended by combinations of fingers on your fully outstretched arm are the same for all viewers. This is due to the fact that the hand's size is proportional to the arm's length. A shorter arm is attached to a smaller hand while a longer arm is attached to a larger hand, thus the angle measured remains the same. If you hold your arm fully outstretched, your little finger, when sighted down your arm, is one degree wide. Your three middle fingers is five degrees, your fist, 10 degrees, and the distance between your little finger and your pointer finger is 15 degrees no matter what your age or size.

The spring constellations, Leo and Virgo, are setting in the W while the fall constellation, Pegasus, is rising in the E. Look for red Antares (Scorpius) glowing in the S. If one has access to a dark site, the Milky Way (containing the star fields of Scorpius and Sagittarius) is also nicely visible. The asterism "the big dipper" (Ursa Major) now stands on its "bowl" with its "handle" pointing nearly straight up. Blue-white Vega (Lyra) leads the "summer triangle" across the night sky while in the SW, Arcturus (Bootes) sinks and Spica (Virgo) is about to vanish.

MERCURY becomes visible around mid-month. It will be only about 5 degrees above the WNW horizon a half hour after sunset. I should be bright enough to find in the twilight but will dim as the month progresses. Bright VENUS appears on a slanted line, above and to the left of Mercury. As Venus approaches the Earth, it will brighten throughout the month. MARS also glows in the night sky above and to the left of Venus and is some 40 times less bright. It is too far away for surface detail in all but the largest of amateur telescopes. JUPITER is the brightest object in the very early morning sky. It seems to brighten as it climbs higher in the sky after midnight. Its bands and zones should be quite beautiful through the telescope all month. Don't forget to watch the dance of its four bright moons, Io, Europa, Ganymede and Callisto. Distant SATURN glows in the SW after sunset and sets in the W just before midnight. Its ring system now tilts some 3 degrees to our sight line. Note its bright moon, Titan. A large telescope will show its other large moons, Rhea, Tethys and Dione. The Delta Aquarid meteor shower peaks on the 28th. less than three days after the full Moon (bummer!) and a total Solar eclipse occurs on the 11th...but not for us.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time.; Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times. Unfortunately some of these events may occur during daylight hours in your area.

DATE EVENT
01
Look W at dusk (about an hour after sunset) to see three planets and a bright star for a nearly straight slanted line beginning with Venus, then Regulus (bright star of Leo), then Mars and finally Saturn high above.
03
Look E at 9 PM to see a conjunction (7 degrees) of the Moon and Jupiter.
06
The Earth is at aphelion (farthest point in its orbit from the Sun, some 94.5 million miles away) at 7 AM.
08
As dawn approaches, look for a pseudo-conjunction (2 degrees) of the thin crescent Moon and the open star cluster, the Pleiades (M45) of constellation Taurus.
09
Look W at dawn to see a very close pseudo-conjunction (about 1 degree) of Venus and the bright star Regulus (Leo).
11
A total solar eclipse occurs along a narrow band that passes through the South Pacific and South America.
12
Look NW at 9 PM to see a conjunction (4 degrees) of the Moon and Mercury.
14
Look W at 9 PM to see a conjunction (6 degrees) of the Moon and Venus.
15
Again look W at dusk to see four planets and a bright star for a slanted, straight line. Only this time, it begins with Mercury, just above the horizon, and continues to Saturn. Only this time, Venus and Regulus have traded places in the line.
16
Look W at 1 AM to see a conjunction (6 degrees) of the Moon and Mars.
28
The Southern Delta Aquarid meteor shower peaks around dawn. Unfortunately there is a nearly full Moon so only the bright meteors will be visible. If we are lucky we should be able to see about 5 events/hour with meteors coming from different directions. However, this is the beginning of next month's Perseid shower which peaks just after the new Moon and could be very nice!
31
Look S at 5 AM to see a conjunction (7 degrees) of the Moon and Jupiter.
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Lunar Almanac for May 2010

Phases of the Moon Phase and Date(s)

Best viewed before local midnight

New
11

Deep Space Objects

1st. Qtr
18

Planets & Moon

Full
25

Moon

Last
Qtr 04

Deep Space & Planets

Topic of the month: Libra, the seventh Constellation of the Zodiac

The Constellation Libra, was known in ancient times as the Balance or the Scales .  It is the seventh sign of the Zodiac and is thought to have been "created" during Roman times.  However, the ancient Greeks and Arabs refered to it as the "claws of Scorpius".  It was associated with the equinox which has now moved westward into the Constellation Virgo.  The Balance or Scales was probably associated with Roman Law.

Libra is an early summer Constellation placed between Virgo and Scorpius.  It can be located by its two brightest stars, Alpha ( a ) and Beta ( b ) and its next two brightest, Gamma ( g ) and Sigms ( s ).  These four stars form a crooked trapezoid in the summer night sky.  Although Libra has few stars, there are some interesting deep space objects: a globular star cluster, a small planetary nebula and a few dim galaxies, as well as a number of double star systems.   

--See you next month!
Ron, the star geezer

***Editor's Note from Astra: The chart below was generated using Stellarium plantarium software as described below.

 

The star chart above was generated by Stellarium, a free open source planetarium program. The above image was created by Dawn Jenkins, using Stellarium and a graphic editing program to format the image for this web page. Editing was done for educational purposes only. Stellarium offers much more to amatuer astronomers and is being used in planetariums and to guide telescopes in the field. Simple charts like the one above can be used on the internet for non-profit, illustration purposes. Proper credit is due of course! Thank you to the makers of this fine program from Astra's Star Gate.

 

This installment of "Whats Up?" is ©2010 Ronald A. Leeseberg, encoded by Dawn Jenkins for Astra's Stargate.

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