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The following is a discussion of a few astronomical objects to see up in the sky this week, July 27 to August 2, 2008.

This Week in Astronomy History

On July 29, 1958 President Eisenhower signed the National Aeronautics and Space Act of 1958 establishing the National Aeronautics and Space Administration. On July 30th, 1971 Apollo 15 landed near Hadley Rille on the Earth's moon.

International Space Station

The ISS is visible in skies over Denver in the late evening this week. The passes are low in the northwest and visible for only a couple minutes or less. Brightest passes are on Thurs at 10:31 pm, Fri at 10:29 pm, and Saturday at 9:20 pm.
Check www.heavens-above.com for times specific to your location.

Sun

Sunday July 27 sunrise is 5:57 am and sunset is 8:21 pm MDT

Saturday Aug 2 sunrise is 6:02 am and sunset is 8:15 pm MDT

(for those of us at 40 degrees north latitude)

There are no active regions visible on the solar disk as of Sunday (July 27)
For more information about the Sun and current solar activity check www.swpc.noaa.gov

Moon

As the week begins the Moon is at lunation 25. It is new on Aug 1 at 4:12 am. It is at lunation 1.7 on Saturday.

Planets

If you have a clear view to west Saturday evening you might try to spot the thin crescent Moon, Venus, Mars, and Saturn around 8:45 pm.

This week look for planet Jupiter in the sky toward the south as soon as it is dark. It is easy to find as it is the brightest object visible that time of the evening. It is in constellation Sagittarius aka "the tea pot" and is quite bright at magnitude -2.5 . As viewed from a telescope on earth, the diameter is 46.6 arc sec across.

The Great Red Spot is a giant storm which may have been raging in the atmosphere of Jupiter for hundreds of years. Giovanni Cassini observed a spot on Jupiter in 1665 although the observational records are not conclusive that it is the same spot visible today. Its reddish color was first noted in the 1800s.

For observers in the Denver area, the spot is visible at the following times this week:
Mon July 28 at 2:35 am>
Mon July 28 at 10:26 pm
Wed July 30 at 4:13 am
Thurs July 31 at 0:04 am (Excellent position)
Sat Aug 2 at 1:42 am
Sat Aug 2 at 9:33 pm

For more information about observing Jupiter's red spot see
http://www.skyandtelescope.com/observing/objects/planets/Transit_Times_o...

You may also view Jupiter's moons moving across the disk. Io transits July 29 around 0:40 am followed by its shadow at 1:09 am; Egress is at 2:56 am.
On July 31st Europa's shadow begins to transit across the disk at 9:10 pm; Europa egresses at 10:50 pm.

For information about transit times of Jupiter's moons see http://www.skyandtelescope.com/observing/objects/planets/3307071.html

Comets

Comets are sometimes called 'dirty ice-balls' and contain frozen material or volatiles that change from a solid to gaseous state when heated. A comet's atmosphere or 'coma' is formed from frozen gas which vaporizes and drags small dust grains into the surrounding space.

C2007 W1 Boattini is in constellation Aries, It is magnitude 7.7 in brightness and its coma is 10 arc minutes across. Recent images show a tail.

15P Finley is in constellation Taurus. It is magnitude 10.3 in brightness.

C2008 J1 Boattini is in constellation Cepheus, magnitude is 10.3

C2007 N3 Lulin is in constellation Sagitarrius, magnitude 11.9

C2007 G1 LINEAR is in constellation Lupus, magnitude 11.3

C2006 OF2 Broughton is in constellation Perseus, magnitude is 11.5

For finder charts and more information about comets see Seiichi Yoshida's comet pages at www.aerith.net
Check out the Astroleague Comet Club at http://www.astroleague.org/al/obsclubs/comet/comet.htm

Asteroids

3 Juno is in constellation Ophiuchus
11 Parthenope is constellation Capricornus
Check out the Astroleague Asteroid Club at http://www.astroleague.org/al/obsclubs/asteroid/astrclub.html

Dark Sky Objects

Around 11 pm, The constellation Sagittarius is directly south and in prime viewing position. Above the spout of the teapot locate Messier 8, the Lagoon Nebula. The lagoon is a oval cloudlike patch that may be seen naked eye in a dark sky location. A bright open cluster called NGC 6530 provides a background sprinkle of stars in the northeastern portion. The luminscent glow of this impressive emission nebula is divided in two by a dark broad lane of dust. It is estimated to be 4100 light years distant.

Slew about 1.5 degrees north of the Lagoon and a few arc minutes to the west and you will come across the Trifid Nebula, Messier 20. Put on a UHC or OIII filter and view this relatively bright nebula which is divided unequally by 3 radial dark lanes. It is marvelous to photograph as it is a wonderful color combination of an open cluster, a bluish reflection nebula in the north and a reddish emission nebula in the south.

Meteor Showers

The Perseid meteor shower began on July 17, peaks Saturday Aug 12, and ends Aug 24. The Delta Aquarids meteor shower is quite active this week as well. Also, the sporadic rate increases this time of year . (Sporadic meteors are those not associated with a particular radiant). The best time to look for meteors is about 2 am to 4:30 am. About 25 or so per hour may be visible in dark early morning skies this week.

For more information about observing meteor showers see http://www.amsmeteors.org/lunsford/
You may also be interested in the Astroleague's Meteor club http://www.astroleague.org/al/obsclubs/meteor/metrcl.html

Summary

This week you can view the giant red spot and watch shadows from Jupiter's moons move across its upper atmosphere. If you have a 10 inch or larger telescope you can see some faint comets and asteroids. You may also view some bright nebula and dust lanes and look for meteors in the early morning sky.

The Weekend Under the Stars at Fox Park, Wyoming sponsored by the Laramie and Cheyenne Astronomy Clubs begins this Thursday.

See Cheyenne Astronomy Club website at http://home.bresnan.net/~curranm/ for more information.