raben.com

Discussion of some astronomical objects that may be seen during the week of July 20 to July 26, 2008.

You may subscribe at the itunes store (640x480 pixels, 55 megabytes) or download a HD 720P high resolution version of this astronomy video from the Astroleague website (1280x1024 pixels, 174 megabytes).

International Space Station

The International Space Station makes some bright passes over the Denver area early in the week.
On Sunday July 20 at 4:05 am the ISS appears in the NW and disappears at 4:11 am in the southeast. (magnitude -2.5)
On Sunday evening at 10:06 pm the ISS appears at 10:06 pm in the west and disappears in the north-northeast at 10:11 pm MDT (magnitude 0.0)
On Monday July 21st it appears at 8:55pm in the west-southwest and disappears in the northwest at 9:00 pm MDT (magnitude -2.2)
On Tue July 22 it appears at 9:18 pm in the west and disappears in the north-northeast at 9:23 pm (magnitude 0.1)
Other passes this week are much dimmer, low and quite brief. Check www.heavens-above.com for times specific to your location.

Sun

On Sunday July 20 sunrise is at 5:51 am and sunset is at 8:27 pm On Saturday July 26 sunrise is at 5:56 am and sunset is at 8:22 pm MDT For more information about the Sun see www.swpc.noaa.gov

Moon

As the week begins, the moon is at lunation 18.
It is in 3rd quarter on Fri July 25 at 12:42 pm.
It ends the week at lunation 24.
Thirty nine years ago this Sunday (July 20, 1969), Neil Armstrong and Buzz Aldrin set foot on the Moon's Sea of Tranquility.

Planets

You may be able to spot the planet Venus just barely above the western horizon around 9pm in constellation Cancer. It is currently magnitude -3.8. Around 9:30 pm you can see Mars and Saturn very low and nearly straight west in the constellation Leo. The semidiameter of Mars is 4.2 arc sec and it is +1.7 magnitude in brightness. Saturn is magnitude +1.2 in brightness and the semidiameter is 16.4 arc sec.

The planet Jupiter may be seen low in the southeast in the constellation Sagittarius as the sky darkens in the early evening. It is magnitude -2.6 in brightness and the semidiameter is 46.9 arc sec. The great red spot crosses the center of Jupiter at the following times this week:

Mon morning July 21 at 1:39 am
Mon evening July 21 at 9:31 pm
Wed morning July 23 at 3:17 am
Wed evening July 23 at 11:09 pm (excellent)
Fri morning July 25 at 3:55 am (low)
Sat morning July 26 at 00:46 am (excellent)
Sat evening July 26 at 8:38 pm (low)

On Monday July 21st, Jupiter's moon Io starts its transit across the disk at 10:55 pm followed by its shadow at 11:14 pm. Transit ends around 01:12 am.

Comets

Here are some comets to locate in the evening sky before the moon rises. C/2008 J1 Boattini is in constellation Cepheus and is magnitude +10.2
C/2007 N3 Lulin is in constellation Sagittarius and is magnitude +11.8?
C/2007 G1 Linear is in constellation Lupus and is magnitude 11.3
C/2007 W1 Boattini is in constellation Aries but the Moon may make it difficult to spot.

Meteor Showers

The annual Perseid meteor shower continues this week. Unfortunately the moon will obscure most of them, though a few of the brighter ones may be visible. The Perseid meteor shower began on July 17, peaks on Aug 12, and continues through Aug 24. Best time to view meteors is in early morning, about two to three hours before sunrise. See www.amsmeteors.org for more info. Also checkout the Astroleague Meteor Club at http://www.astroleague.org/al/obsclubs/meteor/metrcl.html

Summary

This week you can see the International Space Station, take a look at Jupiter's Great Red Spot, view some comets, and maybe some meteors. Join the Longmont Astronomical Society www.longmontastro.org or other astronomy club near you to learn more about the many great objects visible in the night sky.