Saturday August 20th Black Star Canyon star party
By: Steve Short
August 17, 2011 6:16AM PDT
Views: 3634

BSC Star Party Notice - Saturday August 20th, 2011


Hello Fellow OCA club members!


This Saturday, Don plans to open the gate around 7:00 pm, which is about a half hour before the sun sets. Don Stoutenger (714) 271-2646 will be the star party host as I will be competing in the World Bodysurfing Contest this weekend.  As a special treat, Matt Otta will be giving a night sky tour when it gets dark. He knows the sky well and has even run telescopes on Mt. Wilson.


The weather report for this Saturday indicates that Orange County will be clear and very warm again, with humidity at 30% . But keep an eye on the OCA website where I will post a notice on the home page should the star party be cancelled for any reason.


There will be a 3rd quarter moon that doesn’t rise until late so we should have fairly 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 (the 1st farm gate is the Xmas Tree farm). 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.


Warning:  No Pets allowed!  (This is an Irvine Ranch Conservancy property rule)



The ISS (International Space Station) will not make any visible passes Saturday evening nor will the HST (Hubble Space Telescope). There will be no visible Iridium flares Saturday evening at Black Star Canyon but I am sure we will see a few dim satellites pass over as we are looking up in the sky.


~Mercury, (Mag ?) goes down at 7:25 pm just before the sun sets so will not be seen this Saturday evening. It passed between the Sun and Earth August 16th (Inferior conjunction) so is lost in the Sun’s glare until month’s end. It is about 57 million miles from Earth in constellation Leo the Lion.

~Venus, (Mag -3.8) will not be seen Saturday evening as it sets about 7:45 pm and rises about 6:15 am in constellation Leo. Unfortunately, Venus disappears in the Sun’s glow and will not be seen until late September. Venus is now about 161 million miles from Earth.

 ~Mars, (Mag 1.4) is now in Constellation Gemini setting about 5:00 pm so cannot be seen this Saturday evening. It rises just after 2:40 am so can be seen a few hours before sunrise. It is about 192 million miles away, just a 4.5” disk so still too far away to see any detail on the planet.

~Jupiter, (Mag -2.4) will rise about 11 pm in constellation Aries so finally can be seen again at a Saturday evening BSC star party. It now is about 430 million miles from Earth getting a little closer every day. It will outshine any other object in the sky and moon Ganymede will be east of the big planet while moons Europa and Calisto will be to the west. Calisto will be far to the west and moon Io will be transiting in front of the planet.

~Saturn, (Mag 0.9) rises about 10 am Saturday in constellation Virgo so will be visible low in the sky at the BSC star party, setting about 10 pm. Saturn is about 956 million miles away slowly moving further from Earth. The rings are tipped about 9 degrees from edge on and the planet disk is about 16” across. Giant moon Titan will be far east of Saturn with moon Rhea slightly east and Enceladus will be transiting behind Saturn. Moons Tethys & Dione will be just west of the planet.

~ Uranus, (Mag 5.8) will not rise until 9:20 pm this week in constellation Pisces so can be seen Saturday evening at BSC before we close. It shows up as a small 3.6” blue-green disc in a telescope. It is about 1.795 billion miles away, moving closer to Earth.

~ Neptune, (Mag 7.8) is in constellation Aquarius, about 2.697 billion miles away this week slowly moving closer to Earth. It is seen as a bluish gray 2.3” disc in a telescope and we should be able to see it at BSC this Saturday evening, as it rises about 7:50 pm. Neptune can be seen throughout the night as it does not set until about 6:45 am.

~ Pluto, (Mag 14.0) rises at 4:25 pm and reached opposition and peak visibility in late June. It is 2.921 billion miles from Earth in constellation Sagittarius slowly getting farther from Earth. Since it is so dim, you will need a 10” or larger telescope to see it visually at BSC. It lies south of M17 and due west of M25 about .25 degrees from bright magnitude 5.5-6.1 yellow star Y Saggittarii.  The 2011 July issue of Sky & Telescope Magazine shows the path Pluto is following.



The August Perseid meteor shower peaked August 13th when one might see up to 120-160 meteors per hour but the full moon interfered. We normally see a few stray meteors at every BSC star party even when no meteor shower is expected.



One of the brightest comets visible right now is magnitude 7.9 Comet P/2007 R5 Soho in constellation Corvus the Crow. It is 95 million miles away with a period of 3.99 years. This comet might be spotted from BSC this Saturday evening about 5 degrees north of Corvus and below and to the right of Saturn.


Another bright magnitude 8.4 Comet C/2009 P1 Garradd is in constellation Delphinus. We should be able to see this comet Saturday evening. The comet is heading northwest and if it brightens as expected, it will become visible to the naked eye in early 2012. It is now 130 million miles from Earth and can be found below the Summer Triangle Altair/Deneb side in the Dolphin.


Brightest visible asteroids:

Minor Planet 4 Vesta (Mag 5.9), the 2nd most massive object in the asteroid belt, can be found inside the bottom of constellation Capricornus.  Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 117 million miles from Earth at this time and has an orbit period of 3.63 years. It will become visible  shortly after sunset so might be seen at the BSC star party. NASA’s Dawn spacecraft has just gone into orbit around this asteroid and will study it for a year getting as close as 110 miles from its surface.


Minor Planet 1 Ceres (Mag 8.1) is the biggest object in the asteroid belt with a diameter of about 590 miles. It is in constellation Cetus the Whale and can be found  in front of the Whale’s head just below its nose. Ceres is about 196 million miles from Earth and has a period of 4.60 years. It was discovered in 1801 and for 50 years was classified as the 8th planet. It will be visible Saturday evening starting about 9 pm so might be seen at the BSC star party. This asteroid will be the next stop for the Dawn spacecraft.


Deep Sky:

This month let’s consider looking at some Messier objects above the Sagitarius “Teapot” in the vicinity of Pluto, which is between M24 & M25:


M17 (Mag 7) is a nebula and open cluster Messier observed in 1764. It is 3,000 light years away and the nebula spans 40 light years while the cluster spans 8 light years. To locate this object, find 4.5 magnitude star Gamma Scuti and then look a few degrees below for a 5th magnitude star and M17 will be .25 degrees below that star. The nebula should become apparent as a bright bar will stand out.


M25 (Mag 4.6) is an open cluster Messier observed in 1764. It is 2,000 light years away and the cluster spans 19 light years. It contains about 30 stars, the brightest is a magnitude 6.7. Its age is estimated to be 89 million years. It can be found just 3 degrees below M17 and to the left (west).


M24 (Mag 3.5 estimates range between 2.5-4.6) is a thick patch in the Milky Way that Messier observed in 1764. It is sometimes called the Small Sagittarius Star Cloud which consists of millions to perhaps a billion or so stars “clumped” together in the same “area” or direction. It is about 1 degree north of the 4th magnitude star Mu Sagittarii or 3 degrees east of M25.



Don't forget to bring your gloves, coats & sweaters because it can get cold after 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 the sky to darken. Please remember to cart off all your trash as there are no garbage cans at BSC. Hope to see you there.


Your OCA star party host,


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