Saturday May 12th Black Star Canyon star party

Posted On May 9, 2012

BSC Star Party Notice  Saturday May 12th, 2012


Hello Fellow OCA club members!


This Saturday, I plan to open the gate around 7:15 pm, which is about a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will be sunny but partly cloudy Saturday. So keep an eye on the OCA website “Home” page (below the next speaker info) where I will post a notice should the star party be cancelled for any reason.


We should have dark skies as the last quarter Moon will not rise until after midnight Saturday. 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 OC Parks and Nature Conservancy rule).



  The ISS (International Space Station) will not make any visible passes Saturday evening.

  The HST (Hubble Space Telescope) will also not make any visible passes Saturday evening.

But we will get to see an Iridium flare Saturday evening at 8:06 pm up at 68 degrees altitude in the ESE (106 degrees) from Iridium satellite #59 that will be a bright -1.0 magnitude. I am sure we will also see a few dim satellites pass overhead as we are looking up in the sky.

Planets & Pluto:

~Mercury, (Mag -0.4) sets at 6 pm so cannot be seen this Saturday evening. It is about 108 million miles from Earth in constellation Pisces with maybe a 6″ diameter disk. You might spot it 30 minutes before sunrise just 3 degrees above the horizon.

~Venus, (Mag -4.5) should be seen Saturday evening until it sets about 10:30 pm in constellation Taurus. Venus is now about 36 million miles from Earth, going from 26 % lit this month to 1% swelling from a 38″ disk to 57″. On Saturday evening Venus should be 14% lit with a 47″ disk.

 ~Mars, (Mag  0.1) is still in Constellation Leo, just under the Lion, rising about 1:45 pm so is visible high in the sky as the sun sets. It is about 94 million miles away now with a 10″ disk at May1st that will shrink to 8″ at month end so small scopes might struggle to see some detail on the red planet Saturday when it is just a 9″ disk. The white north polar cap tips towards Earth now and you might see some dusky markings on the planet’s surface under dark skies.

~Jupiter, (Mag -1.8) will set about 7:45 pm in constellation Aries Saturday evening as the Sun sets, so will not be seen. It now is about 560 million miles from Earth getting a little farther every day.

~Saturn, (Mag 0.7) will be in constellation Virgo this Saturday, just 5 degrees from bright star Spica, and since it rises at 5:30 pm, will be visible just before sunset.  Saturn is about 819 million miles away slowly moving farther from Earth. Saturn’s globe measures 19″ across at the equator but only 17″ from pole to pole because it is a fast spinning gaseous planet. The rings span 43″ and tilt 14 degrees to our line of sight at mid month. That is a healthy tilt so will provide observers with a good look at the dark Cassini Division that separates the two brightest rings. Largest moon Titan will be west of Saturn with moons Dione & Tethys a bit closer and more in line with the rings. Moon Enceladus will be just east of Saturn with moon Rhea far to the east.

~ Uranus, (Mag 5.9) will be in constellation Cetus this Saturday evening and sets about 4 pm so will not be seen at the BSC star party. It shows up as a small 3.4″ blue-green disc in a telescope if you want to catch it in the morning as it rises about 4 am. It is about 1.935 billion miles away from Earth.

~ Neptune, (Mag 7.9) is in constellation Aquarius, about 2.811 billion miles away this week slowly moving closer to Earth. It is seen as a bluish gray 2.2″ disc in a telescope. We will not be able to see it at BSC this Saturday evening, as it sets about 1:30 pm not rising until about 2:30 am.

 ~ Pluto, (Mag 14.0) does not rise until 11:10 pm so might be seen Saturday evening.  It is 2.936 billion miles from Earth in constellation Sagittarius slowly getting closer to Earth. Since it is so dim, you will probably need a 10″ or larger telescope to see it visually when it rises about 1 am.  The 2012 May issue of Astronomy Magazine shows the path Pluto is following this month on page 43.


The Eta Aquarid meteor shower peaked before dawn May 5th but a full Moon washed out the shower. However this shower is active through May 28th from particles left by Halley’s Comet passes. The radiant will be near star Eta Aquarii. We normally see a few sporadic meteors at every Black Star Canyon star party.


Brightest visible Comets:

The magnitude 9.7 Comet C/2009 P1 Garradd is in the constellation Lynx so can be viewed this Saturday evening at sunset through dawn. The comet is now heading southward and will pass between Leo the Lion and the Gemini Twins. It is now 224 million miles from Earth traveling back into the depths of the solar system. The 2012 May issue of Astronomy Magazine shows the path this comet is following this month on page 42.


Brightest visible asteroids:


Asteroids Ceres and Vesta are too close to the Sun to be spotted this month.


Minor Planet 7 Iris (Mag 9.6) is in constellation Libra this month about 10 degrees west of the Scorpion’s head and 10 degrees east of Spica. It is about 180 million miles from Earth at this time and has an orbit period of 3.69 years. It is about 124 miles in diameter. This asteroid was discovered in 1847 by J. R. Hind from London, the seventh asteroid ever found but his first.


Minor Planet 5 Astraea (Mag 9.6) is in constellation Leo this month and is found in the stars of the rump of the lion. On Saturday, it will be a half degree south of 4th degree star Iota Leonis. It is about 180 million miles from Earth at this time and has an orbit period of 4.13 years. It is another potato shaped rock about 75 miles wide. This asteroid was discovered in 1845 by amateur astronomer Karl Ludwig Hencke accidentally as he searched for asteroid Vesta. It should become visible shortly after sunset so might be seen at the BSC star party.


Minor Planet 6 Hebes (Mag 10.0) has a diameter of about 120 miles, contains ¬Ω percent of the mass of the entire asteroid belt and was the 5th asteroid discovered. It is in constellation Leo and can be found on the back of Leo the Lion all month long. It is about 348 million miles from Earth and has a period of 3.78 years. It was discovered July 1, 1847 by Karl Ludwig Hencke, his 2nd and last asteroid discovery. It will be visible Saturday evening after the sun sets so might be seen at the BSC star party.


Deep Sky:

This month let’s consider looking at some colorful named galaxies near Ursa Major:


M51 (Mag 8.1) the famous Whirlpool Galaxy, is a spiral galaxy, 37 million light years from Earth that spans 118,000 light years. It was first observed by Messier in 1774 and he called it a faint nebula with no stars. Easy to find as it forms the base of a right triangle with Big Dipper handle stars Alkaid & Mizar.


M63 (Mag 8.6) is another spiral galaxy called the Sunflower Galaxy, 30 million light years from Earth that spans 105,000 light years. It was first observed by Messier in 1779 and he called it another faint nebula with no stars right next to an 8th magnitude star. It is found just off a line between the stars Alkaid and Canum Venaticorum. The 9th magnitude star sitting on its edge can be used for positive identification,