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What's
Up In August
Double Stars
Beta Aquilae is relatively fixed, with a faint red dwarf
companion: 3.7, 11.6; PA 5º, separation 13".
Zeta Aquilae also has a very faint dwarf companion, of
uncertain period: 3.0, 12; PA 53º, separation 6.5".
Pi Aquilae: 6, 7; PA 111º, separation 1.4".
Chi Aquilae is a close binary with the separation slowly
decreasing: 5.6, 6.8; PA 77º, separation 0.5".
Variable Stars
Eta Aquilae is a cepheid variable: 3.48-4.39 with a period
of 7.18 days (more precisely 7 days, 4 hours, 14 minutes and 21.8 seconds).
The magnitude changes very gradually throughout this time period, and is
easily noticed with binoculars (using beta Aquilae, 3.7, as a reference).
Sigma Aquilae is an eclipsing binary (EB type), fluctuating
between 5.14 and 5.34 every 1.95 days. The combined mass is equal to twelve
suns although their densities are each only about one tenth of the sun's.
R Aquilae is a long period variable: 5.5 to 12 every 284.2
days. The 2000 maximum should occur on 4 June.
Deep Sky Objects
NGC 6709 is a loose cluster comprised of about forty stars.
It's approximately 2500 light years away and is located five degrees SW
of zeta Aquilae.
NGC 6781 is a fine planetary nebula that is relatively
bright and large, being about 2' in diameter. This grey puffball of light
is reminiscent of the Owl Nebula in Ursa Major. The southern portion of
the nebula is slightly brighter than the northern portion.
B143-4 is a classic example of a dark nebula. It is relatively
easily seen in binoculars, lying just west of the star Gamma Aquilae, which
is near the bright star Altair. The nebula is over a degree in size, and
is seen as an "E" shaped region which is devoid of stars.
Other objects which you may want to track down are NGC
6738, 6755, and 6760, and open cluster Cr 401.
Sky Events
August 06 - The Moon will be at First Quarter at 8:03
pm CDT.
August 11 - Uranus at opposition in the constellation
of Capricornus. Under dark skies Uranus can be seen with the naked eye
if you know exactly where to look. Its pale blue disk is visible with small
telescopes. Twenty moons orbit Uranus, more than any other planet in the
solar system
August 12 - Saturday morning around 4 am the Perseid Meteor
Shower will peak. The waxing gibbous moon will set about one hour before
dawn, giving dark skies for a brief period during the time when the meteors
should be most active. However, since the Perseids meteors are usually
bright and fast some meteors will be seen even with the bright moon interfering
earlier in the night. The meteor radiant rises in the northeast and is
high in the east as dawn approaches.
August 15 - The Moon will be Full at 12:15 am CDT. This
moon is called the Green Corn Moon or Grain Moon.
August 22 - The Moon will be at Last Quarter at 1:52 pm
CDT. The Moon will be near Jupiter and Saturn this morning.
August 23 - The moon passes 3 degrees south of Jupiter
at 5:00 am
August 29 - The Moon will be New at 5:21 am CDT.
August 31 - The crescent moon will pass 4 degrees N.N.E
of Venus
Sky Summary
August is one of the best months for stargazing. Right
after sunset on warm August evenings you can see the richest parts of the
Milky Way looking towards the constellations Scorpius and Sagittarius,
with the rich starfields of Cygnus the Swan high overhead. Under dark skies
you can spend hours scanning the skies with binoculars. Many open and globular
star clusters, nebulae are visible in binoculars under the dark skies of
Fort McKavett, Garner State Park, and Guadalupe State Park, away from city
lights.
Mercury, Mars, Jupiter and Saturn are visible after midnight
or before dawn in August. The evening sky has the faint outer planets Uranus,
Neptune and Pluto.
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