Vern’s Weblog

I spent the weekend near Fox Park, WY at the annual “Weekend Under The Stars” (WUTS) star party. Excellent conditions this year, no dew, mostly clear all night, temperature in the low 50s, no wind, and fair to good turbulence. Around 2 am Monday morning I counted about 30 stars within the great square of Pegasus indicating that the limiting magnitude was around +6.5 (I’m an old geezer, those with good eyesight would do better).

Just after midnight I abandoned the scope, put a tarp on the ground and got out some cushions and blankets from the RV. Laying on the ground next to my wonderful wife, looking up into the blackness at the incredible Milky Way and the numerous brilliant stars from a dark sky site was a great experience. It gives a much different perspective than our normal (vertical) view as you can see so much more of it (highly recommended).

My meteor counts early Monday morning Aug 13 were:

0:30 to 1:30 am : 57 total (54 Perseids, 3 Delta Aquarids)
1:30 to 2:30 am : 77 total (73 Perseids, 4 Delta Aquarids)

These are pretty close to the typical peak rate for the Perseids (60 to 80 per hour).

The following is a list of some astronomical objects to see in the sky the week of Aug 12 thru Aug 18, 2007. Some of the events and times given are specific to the Colorado front range (40° N and the MDT timezone).

Highlights

• Perseid meteor shower continues this week (peak days Aug 11 to 15)
• Spot the thin crescent moon after sunset on Mon Aug 13
• Watch the International Space Station this week Tues thru Sat. in the early evening
• CU Mountain Research Station star party this Fri Aug 12 thru Sat Aug 13 (See www.boulderastro.org) Canceled, meeting at Sommers-Bausch Observatory on Sat Aug 13 at 7 pm instead.

International Space Station
The ISS passes over each night this week around 8 to 10 pm. The brightest passes are on:

Tues 14 Aug ISS rises in the NNW at 9:53:54pmand disappears in the NNE at 9:56:08 pm (magnitude -0.0)

Wed 15 Aug ISS rises in the NW at 10:16:01 pm and disappears in the NNW at 10:17:32 pm (magnitude -0.0)

Thur 16 Aug ISS rises in the NNW at 9:03:52 pm and disappears in the ENE at 9:07:37 pm (magnitude -0.0)

Fri 17 Aug ISS rises in the NW at 9:25:55 pm and disappears in the NE at 9:29:03 pm (magnitude -1.3)

Sat 18 Aug ISS rises in the NNW at 8:13:45 pm and disappears in the ENE at 8:17:49 pm (magnitude -0.1)
Sat 18 Aug ISS rises in the WNW at 9:48:15 pm and disappears in the WNW at9:50:31 pm (magnitude -1.5

Sun
The Sun rises 6:11 am to 6:14 am MDT and sets 8:04 pm to 7:56 pm MDT. Region 10966 is near the center of the solar disk but is quite small. It will rotate out of view on the west limb Thurs. Solar activity is expected remain at very low levels this week.

Moon
The Moon is new this Sun, Aug 12 at 5:02 pm MDT.
Mon Aug 13 try to spot the thin crescent moon before it sets at 8:30 pm (1.3 days)
Tues Aug 14 Craters Gauss and La Perouse
Wed Aug 15 Craters Endymon, Furnerius, Langrenus, Messala, and Petavius. Check out the Mare Crisium region as well.
Thur Aug 16 Craters Atlas, Cleomed, Macrobius, Messier, Taruntius, and Watt. The Vallis Rheitta alignment of closely overlapped craters.
Fri Aug 17 Craters Fracastorois. Gartner, Hercules, and Piccolomini
Sat Aug 18 Mare Tranquillitatis; and craters Catharina, Cyrillus, Lamont, Theophilus; and

Planets
Mercury is too close to the Sun and not visible.
Venus is too close to the Sun and not visible (inferior conjuction on Sat).
Mars rises 0:33 to 0:22 am MDT in constellation Taurus. It is +0.4 magnitude in brightness, 7.6 arc sec across, and 86% illuminated.
Best time to view Mars is just before sunrise when it is high up (around 5 am). The martian feature Mare Cimmerium is visible early in the week but rotates from our view. Later in the week the prominent features visible are Mare Sirenum, and Solis Lacus. The following is the center longitude of Mars at 5 am:
Sun Aug 12: 197
Mon Aug 13: 187
Tues Aug 14: 177
Wed Aug 15: 168
Thur Aug 16: 158
Fri Aug 17: 148
Sat Aug 18: 206
See the annotated Mars map by Damian Peach.

Jupiter is directly south after dark in constellation Ophiuchus. The Great Red Spot (GRS) crosses center at the following times this week:
Aug 13 at 02:26 am
Aug 13 at 10:17 pm
Aug 15 at 11:56 pm
Aug 18 at 01:35 am
Aug 18 at 09:26 pm
The GRS is visible about an hour before and after the central meridian crossing.

Saturn is too close to the Sun and is not visible.

Uranus is in constellation Aquarius, magnitude 5.7, and 3.6 arc-sec in diameter.

Neptune is in constellation Capricornus, magnitude 7.8, and 2.5 arc-sec in diameter (at opposition on Mon Aug 13).

Pluto is in constellation Sagitarrius, magnitute 13.7, and 0.1 arc-sec in diamter.

Comets
No reasonably bright comets are visible this week.

Asteroids
There are 6 asteroids brighter than magnitude +10 this week. Locations are for Sat. Aug 18 at 10:30 pm MDT.

     Name        Const           RA          Dec      Mag

1 Ceres Cetus 03:23:48 +09 16′38″ 8.8

2 Pallas Pegasus 22:38:03 +07 01′44″ 9.1

4 Vesta Scorpio 16:24:18 -20 10′19″ 7.0

8 Flora Cetus 03:21:06 +10 46′10″ 9.9

40 Harmonia Capricornus 20:40:43 -23 32′36″ 9.8

194 Prokne Aquarius 21:40:46 -04 17′37″ 9.6

Dark Sky
Dark sky week continues you can still view your favorite summer objects.The Moon sets 10:17 pm on Saturday.

Meteor Showers
The annual Perseid meteor shower should peak around 3:00 am on Aug 13 as the Earth passes through debris from comet Swift-Tuttle. The typical peak rate for the Perseid meteor shower is about 60 per hour. In the mid-90s the Earth passed through core areas of the debris and exceeded 400 per hour. The rate varies through the evening starting with around 50% the peak rate (30 per hour) around 9 pm and increasing to around 90% the peak rate by midnight, to 100% the peak rate by 3 am.

The following is a list of some things to see in the sky this week, Aug 5 thru Aug 11, 2007. Some of the events and times given are specific to the Colorado front range (40° N and the MDT timezone).

Highlights

• Perseid meteor shower late this week and early next (Aug 11 to 15)
• Dark sky weekend!
• The 17th annual Weekend Under the Stars (WUTS) star party near Fox Park, WY this Thursday Aug 9 through Saturday Aug 11

International Space Station

The ISS passes over each night this week, however all passes are low in the NW and not bright.

Sun

The Sun rises 6:04 am to 6:10 am MDT and sets 8:13 am to 8:06 pm MDT. Solar activity is expected remain at very low levels this week.

Moon

The Moon is new on Sun, Aug 12 at 5:02 pm MDT.

Planets

Mercury is getting closer to the Sun this week and won’t be favorably placed until November for us in the northern hemisphere (September for those in the southern hemisphere).

Venus will no longer be visible in the evening sky by the end of the week. It will appear again before dawn towards the end of this month.

Mars rises 0:45 to 0:34 am MDT in constellation Taurus. It is +0.4 magnitude in brightness, 7.4 arc sec across, and 86% illuminated.
Currently, the best time to view Mars is just before sunrise when it is high up (around 5 am). The martian feature Syrtis Major is visible early in the week but rotates from our view midweek. By the weekend the prominent features are Mare Cimmerium, Mare Sirenum, and Olympus Mons. The following are the Mars center longitude at 5 am on days indicated:
Mon Aug 6: 255
Tues Aug 7: 245
Wed Aug 8: 236
Thur Aug 9: 226
Fri Aug 10: 216
Sat Aug 11: 206
Sun Aug 12: 197
(See the annotated Mars map by Damian Peach).

Jupiter is directly south after dark in constellation Ophiuchus.
The Great Red Spot crosses the center of Jupiter at the following times this week.

Mon Aug 6 1:38 am
Mon Aug 6 9:30 pm
Wed Aug 8 11:08 pm
Sat Aug 11 0:47 am
Sat Aug 11 8:38 pm

Saturn sets about a half hour after sunset and is lost in bright twilight. It will reappear in the morning before sunrise in early September.

Uranus is in constellation Aquarius, magnitude 5.7, and 3.6 arc-sec in diameter.

Neptune is in constellation Capricornus, magnitude 7.8, and 2.5 arc-sec in diameter.

Pluto is in constellation Sagitarrius, magnitute 13.7, and 0.1 arc-sec in diamter.

Comets

No reasonably bright comets are in good position this week.

Asteroids

There are 6 asteroids brighter than magnitude +10 this week. Locations are for Sat. Aug 11 at 10:30 pm MDT.

Name Const RA Dec Mag
1 Ceres Cetus 03:18:36 +09 05′07″ 8.9
2 Pallas Pegasus 22:42:45 +08 07′04″ 9.2
4 Vesta Scorpio 16:17:38 -19 28′09″ 6.9
8 Flora Cetus 03:09:51 +10 22′36″ 10.0
40 Harmonia Capricornus 20:47:08 -23 00′16″ 9.6
194 Prokne Aquarius 21:44:50 -02 13′01″ 9.7

Dark Sky

It is dark sky weekend on Aug 10-12! Here are some Messier objects I’m planning on visiting this upcoming weekend.
M4 Globular cluster in Scorpius
M7 naked eye open cluster in Scorpius
M8 Lagoon Nebula in Sagittarius is a large, bright emission nebula
M13 Globular Cluster in Hercules is an amazing sight in a large aperature scope at a dark site
M17 Omega or Swan Nebula in Sagittarius.
M20 Trifid in Sagitarius is a reflection and emission nebula
M22 in Sagittarius is a class 7 globular cluster and magnitude 6 in brightness
M27 Dumbbell Nebula in Vulpecula
M16 Eagle Nebula in Serpens
M54 in Sagittarius is a magnitude 7.5 class 3 globular cluster
M57 Ring Nebula in Lyra
M80 globular cluster in Scorpius

Meteor Showers

The annual Perseid meteor shower should peak around 3:00 am on Aug 13 as the Earth passes through debris from comet Swift-Tuttle. The typical peak rate for the Perseid meteor shower is about 60 per hour. The rate varies through the evening starting with around 50% the peak rate (30 per hour) around 9 pm and increasing to around 90% the peak rate by midnight, to 100% the peak rate by 3 am. The meteor display should be good for a couple days before and after the peak on Aug 13.

Lunar craters Messier and Messier A, (located near the center of the image of Mare Fecunditatis below) show unique parallel rays streaming to the west (left).  These rays were probably formed by collisions with different objects impacting at very shallow angles of 1 to 5 ° .

Image taken on Aug 1, 2007 at 00:20 MDT with Celestron Nexstar 11 telescope and Philips Toucam 840K webcam at cassegrain focus. Sky was clear but hazy, turbulence 5/10, no wind, termperature 74°F, location Louisville, CO.