BSC – Saturday 10 April 2010
Hello Fellow OCA club members!

This Saturday I plan to open the gate about 6:45 pm, a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will be partly cloudy that day with 70% humidity. Let’s hope the weather report is wrong but watch for a notice on the OCA website home page in case the star party has to be cancelled.  The 3rd Quarter Moon will not rise until well after midnight giving us dark skies. First time visitors might want to get to BSC while it is still light so they can find their way down the dirt road and into the parking area. Remember that you take the 2nd farm gate on the left after turning on Black Star Canyon Road. If you come in after dark, you should drive in with your headlights off!!! The dirt road will be marked with red flashers and you can hold a flashlight out the driver’s window to light up the road directly in front of your car.
Satellites:
The ISS (International Space Station) will not make any visible evening passes this Saturday nor will the HST (Hubble Space Telescope). There will not be any visible Iridium flares this Saturday at BSC but I am sure we will see a few other dim satellites pass over as we are looking up in the sky.

Planets:
~Mercury, (Mag -0.2) sets about 8:45 pm so is well placed to be seen early this Saturday evening. It is only about 67 million miles from Earth in constellation Aries. Mercury will be just below and about 4 degrees to the right of bright Venus, about as high in the sky as it ever gets..
~Venus, (Mag -3.8) will be the brightest object in the sky after the sun sets and can be spotted high in the West in constellation Aries. It will not set until about 8:50 pm and is now about 146 million miles from our planet. Venus will be close to full phase (over 90% lit) and will have nearly an 11″ diameter disk.
~Mars, (Mag 0.3) is now in Constellation Cancer,  traveling eastward getting further from Earth, about 100 million miles away. Mars sets about 3:20 am but rises around 1:15 pm so will be seen high in the sky this Saturday evening at BSC. In the middle of April, Mars will pass just over the Beehive Cluster (M44).

~Jupiter, (Mag -1.9) rises about 5:20 am in constellation Aquarius so the big planet can be seen this month  only at dawn. Jupiter sets around 5 pm so is lost in the sun’s glow and cannot be seen in the evening. It now is about 543 million miles from Earth and getting a little closer every day.

~Saturn, (Mag 0.6) rises about 5:45 pm Saturday in constellation Virgo so will  be visible soon after sunset at BSC Saturday evening.  It sets in the East at 6 am so can be seen in the morning too. Saturn reached opposition March 21^st so be opposite the sun and visible all night long. It is about 795 million miles away moving closer to Earth. The rings tilt only about 2 degrees to our line of sight but they will open again this summer and tilt 10% by year end. Saturday evening big moon Titan will be seen far to the east of Saturn while moon Dione will be east and close to Saturn with moon Tethys even closer. Moon Enceladus will be just to the west of Saturn with moon Rhea a bit further out.

~ Uranus, (Mag 5.9) will rise about 5:45 am in constellation Pisces this week hidden by the sun and then sets about 5:40 pm, washed out by the sun’s glare. When we can see this planet, it shows up as a blue-green disc in a telescope and is about 1.957 billion miles away moving farther from Earth. This planet reached opposition September 17^th and will become easier to see in May.
~ Neptune, (Mag 7.9) has moved from Capricornus last month into constellation Aquarius, about 2.852 billion miles away this week slowly moving closer to Earth. Neptune is now in the area where it was discovered 164 years ago.  It is seen as a bluish disc in a telescope but we will not see it this Saturday as it sets about 3:20 pm. It can be seen just before dawn as it rises at 4:20 am.

 Meteors/Comets/Asteroids:

The Lyrid meteor shower peaks before dawn on April 22^nd where you might see up to 25 meteors per hour in a dark sky. The  radiant is near Vega and the meteors comes from particles left by comet Temple-Tuttle. It is estimated that this annual event deposits 12 tons or more of particles across the entire planet.

Comet 81P Wild 2 (Mag 9.4) is in constellation Virgo just 8 degree east of Spica and about 7 degrees above the Ecliptic. It’s orbit lies close to the plane of our solar system so we see this comet edge-on. That causes us to see the dust tail as a sharp streak rather than the typical fan tail. This comet has closed to about 63 million miles from earth and has a period of 6.42 years. Samples of this comet were returned to earth and contained an amino acid, one of life’s fundamental building blocks.

Comet C/2009 O2 Catalina (Mag 9.6) is in constellation Perseus, just under her rear foot, about 88 million miles from Earth. It has a period of 4,551 years so won’t be seen again for thousands of years. It was discovered by Alex Gibbs July 27^th, 2009 during the Catalina Sky Survey.

Comet C/2009 K5 McNaught (Mag 9.7) is in constellation Cygnus and is about 122 million miles from Earth. It can be found about 5 degrees from the Swan’s head (Alberio) on a direct line back to the tail (Deneb). It was discovered by Rob McNaught May 27^th, 2009 in Australia.

Comet C/2007 Q3 Siding Spring (Mag 11.4) is now about 240 million miles away from Earth in constellation Draco. On Saturday, it will be about 12 degrees directly below the Little Dipper. This comet was discovered August 25^th, 2007 (thus the designation C/2007) by D. M. Burton from the Siding Spring Survey.

Other comets are even dimmer so would be next to impossible to find in any of our scopes.

 
Minor Planet 4 Vesta (Mag 7.0) is the 2^nd most massive object in the asteroid belt with a diameter of just over 329 miles. It is the brightest of all the asteroids and can be found just below the Lion’s head as though it is about to be eaten. It is now is about 152 million miles from Earth and has a period of 3.63 years.

Minor Planet 1 Ceres (Mag 8.3) can be found in constellation Sagittarius directly above the “Teapot” lid.. It is about 220 million miles from Earth and has a period of 4.60 years.

Minor Planet 2 Pallas (Mag 8.5) can be found in constellation Serpens 15 degrees due east of Arcturs. It is about 183 million miles from Earth and has a period of 4.62 years.

Minor planet 532 Herculina (Mag 9.1) is in constellation Ursa Major just 15 degrees (almost) directly north of Leo the Lion’s tail star (Denebola). It is only about 131 million miles from Earth with a period of 4.61 years. It was discovered in 1904 by Max Wolf and is about 138 miles in diameter. This was the first asteroid to have a confirmed asteroid moon – about 45 km orbiting at a distance of about 1,000 km.

Deep Sky:
This month, lets go galaxy hunting (the topic at the April 5^th Go-To SIG meeting) around the Big Dipper:

M81 (Mag 6.8) is a spiral galaxy about 9.5 million light years away with a diameter of 72,000 light years which we see nearly face-on. It is found along a line from Big Dipper bowl stars Phad and Dubbe at the same distance these two stars are apart. Messier observed this object in 1781 but had no idea what it was.

M82  (Mag 8.4) is an Irregular galaxy about 9.5 million light years away that spans 30,000 light years which we see edge-on so it looks cigar shaped. It is also found along a line from Big Dipper bowl stars Phad and Dubbe at the same distance these two stars are apart.  Messier also observed this object in 1781.

   Note: M81 & M82 can be seen in the same eyepiece field of view using a wide angle eyepiece.
M108 (Mag 10.0) is another spiral galaxy about 24 million light years away with a diamater of 56,000 light years which we see edge on, resembling a cigar. It is found just 1.5 degrees from Big Dipper bowl star Merak right along the bottom bowl line. Messier found this object in early 1781.

M109 (Mag 9.8) is another spiral galaxy about 27 million light years away with a diamater of 63,000 light years which we see face on, oval shaped. It is found just a moon’s width from Big Dipper bowl star Phad right along the bottom bowl line. Messier found this object in early 1781

 Don’t forget to bring your gloves, coats & sweaters because it will get very cold as the sun sets and the night approaches midnight when we close. After you set up your telescope, there are three picnic tables where you can sit and eat food you might bring, while waiting for it to get dark. Please remember to cart off all your trash as there are no garbage cans at BSC. Hope to see you there.
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Your OCA star party host,

Steve