Saturday July 23rd Black Star Canyon star party

Posted On July 22, 2011

BSC Star Party Notice – Saturday July 23rd, 2011


Hello Fellow OCA club members!


This Saturday, I plan to open the gate at 7:30 pm, which is about a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will be clear, sunny and warm again, with humidity at 55% and some light winds. 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.


We will have a 3rd quarter moon that doesn’t rise until well after midnight so we will 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 but the HST (Hubble Space Telescope) will make two visible passes.  The first Mag 1.7 pass will start at 8:50:47 pm 10 degrees high WSW rising to 35 degrees  South by 8:54:41 and then drop to 17 degrees SE at 8:57:26 pm. The second Mag 3.5 pass will start at 10:33:10 pm 10 degrees high WSW and drop out of sight 5 seconds later.  There will be one visible Iridium flare Saturday evening at 9:16:42 pm from Iridium (satellite) 47 up at 51 degrees high E (85 degrees) going from Mag -1 to -8.    I am sure we will also see a few dim satellites pass over as we are looking up in the sky.


~Mercury, (Mag 0.6) sets at 9:25 pm not long after the sun sets so might be seen low on the horizon (8 degrees) this Saturday evening. A telescope should show a fat crescent shape of this planet’s 8″ disk. It is about 79 million miles from Earth in constellation Leo the Lion.

~Venus, (Mag -3.8) will not be seen Saturday evening as it sets about 7:30 pm and rises about 5:20 am in constellation Gemini. Unfortunately, Venus disappears in the Sun’s glow and will not be seen until late September. Venus is now about 160 million miles from Earth.

 ~Mars, (Mag 1.4) is now also in Constellation Taurus setting about 5:30 pm so cannot be seen this Saturday evening. It rises just after 3 am so can be seen a few hours before sunrise. It is about 202 million miles away, just a 4″ disk so still too far away to see any detail on the planet.

~Jupiter, (Mag -2.2) will set about 2 pm in constellation Aries way before the sun sets so will not be seen Saturday evening. It now is about 468 million miles from Earth getting a little closer every day. It rises 45 minutes after midnight and then outshines any other object in the sky.

~Saturn, (Mag 0.9) rises about 11:45 am Saturday in constellation Virgo so will be visible high in the sky at the BSC star party not setting until 11:45 pm. Saturn is about 918 million miles away slowly moving further from Earth. The rings are tipped about 7 degrees from edge on and the planet disk is about 17″ across. The bright star near the planet, is 3rd magnitude Gamma Virginis which is now about 3 full moon widths from Saturn. Giant moon Titan will be about a ringed planet distance West of Saturn while Enceladus will look like it is at the outer ring edge just West of the planet. Moons Tethys & Dione will be just East of the planet looking like they are just outside the rings. Moon Rhea will be about a ringed planet distance East of the planet.

~ Uranus, (Mag 5.8) will not rise until 11:15 pm this week in constellation Pisces so probably won’t have time to get high enough to be seen Saturday evening at BSC before we close. When seen, it shows up as a small 3.6″ blue-green disc in a telescope. Since Uranus does rise just before midnight, it can be seen in the morning sky up to dawn. It is about 1.829 billion miles away, moving closer to Earth.

~ Neptune, (Mag 7.8) is in constellation Aquarius, about 2.711 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 9:40 pm. Neptune can be seen throughout the night as it does not set until after 8:30 am. Neptune was discovered 164 years ago, and its orbit is about 164 years so it is now completing its first orbit since German astronomer Johann Galle first spotted it.

~ Pluto, (Mag 14.0) rises at 6:15 pm and reached opposition and peak visibility in late June. It is 2.895 billion miles from Earth in constellation Sagittarius. Since it is so dim, you will need a 10″ or larger telescope to see it visually. It lies about 1 degree west of the 9th magnitude star SAO 161442.



The July Delta Aquarid meteor shower peaks July 30th when one might see up to 20 meteors per hour from the radiant 12 degrees north of star Fomalhaut. We normally see a few stray meteors at every BSC star party even when no meteor shower is expected.



The brightest comet visible right now is magnitude 9.3 C/2009 P1 Garradd in constellation Pegasus. 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 161 million miles from Earth and can be found about 5 degrees east of star Enif.


Then there is magnitude 10.4 Comet P/2007 R5 Soho just a few degrees south of the Beta star in constellation Corvus the Crow. It is 97 million miles away with a period of 3.99 years. This comet might also be spotted from BSC this Saturday evening.


Brightest visible asteroids:

Minor Planet 4 Vesta (Mag 5.9), the 2nd most massive object in the asteroid belt, can be found just a few degrees above the Kappa star in constellation Capricornus.  Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 116 million miles from Earth at this time and has an orbit period of 3.63 years. It will become visible about 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 8.6) 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 223 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 10 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 of summer’s best double stars.


Mu Bootes (Mag 4.3, 7.1 and 7.1, 7.6), is a triple star found just east of Bootes Beta &  Mu stars. At low power it looks like a bright star with a distant companion but at 100X, the fainter star is seen as a close pair. The primary star looks yellow while the fainter stars look Orange. Separation is 109″ & 2.3″ and the close pair has an orbital period of 250 years.


Zeta Cornae Borealis (Mag 5.0 & 5.9), is a pretty bluish white and greenish white star pair. They can be found in Cornae Borealis above the necklace and 5 degrees east of Mu Bootes.  Separation is just 6.3″.


95 Herculis (Mag 4.8 & 5.2) is a lovely pair of stars described as “apple green and cherry red”. Their separation is just 6.3″ and best seen in a 6-8″ scope at 50X or 100X. They can be found far to the east of Hercules, about 5 degrees directly east of Delta Herculis.



Don’t forget to bring your gloves, coats & sweaters because it can get cold after the sun sets and the night approaches midni