Saturday 05/28/11 BSC star party
By: Steve Short
May 25, 2011 4:31AM PDT
Views: 3462

BSC Star Party Notice - Saturday May 28th, 2011


Hello Fellow OCA club members!


This Saturday, I plan to open the gate at 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 and warm, so the May star party should be great. 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 Nature Conservancy property rule)



The ISS (International Space Station) will not make any visible passes Saturday evening but is making visible morning passes all week. The HST (Hubble Space Telescope) will make one magnitude 2.3 visible pass Saturday evening starting at 9:21:25 pm 10 degrees high SW rising to 21 degrees S at 9:24:25 where it will slip out of view.  There will be one visible Iridium flare Saturday evening at 10:49:37 pm from Iridium (satellite) 30 up at 67 degrees high WSW (252 degrees) going from Mag -2 to -6.  I am sure we will also see a few dim satellites pass over as we are looking up in the sky.


~Mercury, (Mag -0.4) sets at 6:15 pm well before the sun sets so cannot be seen this Saturday evening. However, this planet rises just before 5 am so could be seen just before dawn about 5 degrees high. It is about 105 million miles from Earth in constellation Aries.

~Venus, (Mag -3.8) will not be seen Saturday evening as it sets just after 6 pm but can be seen in the morning as it rises about 4:35 am in constellation Aries. It can be  seen just before dawn, brighter than any of the other 3 planets nearby (Mars, Mercury & Jupiter).  Venus is now about 145 million miles from Earth.

 ~Mars, (Mag 1.3) is now also in Constellation Aries setting just before 6 pm so cannot be seen this Saturday evening. It rises at 4:30 am and could be seen just a few degrees above Venus.  It is about 214 million miles away, still too far away to see any detail on the planet.

~Jupiter, (Mag -1.9) will set about 5 pm in constellation Pisces before the sun sets so will not be seen Saturday evening. It now is about 533 million miles from Earth getting a little closer every day. It can be seen 30 minutes before the sun rises below the crescent moon but above Mars, Venus and Mercury.

~Saturn, (Mag 0.7) rises about 3:30 pm Saturday in constellation Virgo so will be visible high in the sky at the BSC star party. Saturn is about 836 million miles away slowly moving further from Earth. The ringed planet will not set until 3:20 am so can also be seen in the early morning sky this month. The rings are tipped about 8 degrees from edge on and the bright star near the planet, just ½ degree away, is 3rd magnitude Gamma Virginis (Porrima), a famous double star. Moon Dione will be just to the west of Saturn and above the rings while Enceladus will be about a ringed planet width further west and finally furthest west will be Rhea. Moon Tethys will be just East of Saturn while giant moon Titan will be further east and slightly above the planet.

~ Uranus, (Mag 5.9) will set at around 3 pm this week in constellation Pisces so will not be seen Saturday evening. When seen, it shows up as a small blue-green disc in a telescope. Since Uranus will rise at 2:50 am, it can be seen in the morning up to dawn. It is about 1.930 billion miles away, moving closer to Earth.

~ Neptune, (Mag 7.9) is in constellation Aquarius, about 2.785 billion miles away this week slowly moving closer to Earth. It is seen as a bluish gray 2.3” disc in a telescope but we will not be able to see it at BSC this Saturday evening, as it doesn’t rise until after 1 am. However, it could be spotted high in the sky before dawn. 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.



We missed the early May 6th Eta Aquarid meteor showers where one might have seen up to 60 meteors per hour looking East before dawn. We normally see a few stray meteors at every BSC star party even when no meteor shower is expected.



The only comet visible right now is dim magnitude 11.4 C/2009 P1 Garradd in constellation Pisces. But it will not become visible until around midnight so we will not get a chance to see it Saturday evening. This comet is heading north and if it brightens as expected, it will become visible to the naked eye in early 2012. It is 292 million miles from Earth and can be found 15 degrees below the southern leg (starting with Beta star Scheat) of the Great Square Pegasus.


Brightest visible asteroids:

Minor Planet 4 Vesta (Mag 7.0), the 2nd most massive object in the asteroid belt, can be found 16 degrees above the middle of constellation Capricornus along the ecliptic. Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 155 million miles from Earth at this time and has an orbit period of 3.63 years. It won’t be visible until about 11 pm so might be seen at the BSC star party.


Minor Planet 1 Ceres (Mag 9.0) is the biggest object in the asteroid belt with a diameter of about 590 miles. It is in constellation Aquarius below the Ecliptic. Ceres is about 291 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 not be visible Saturday evening until 1 am so will not be seen at the BSC star party.


Minor Planet 10 Hygiea (Mag 9.4) is the 4th largest object in the asteroid belt with an oblong diameter of about 220 -310 miles. It is in constellation Libra and can be found about 20 degrees directly in front and above the Scorpion’s 3 head stars.  This asteroid can be seen Saturday evening. Hygiea is about 166 million miles from Earth and has a period of 5.56 years. It was Annibale Gasparis’s first asteroid discovery made on April 12th, 1849. He lived in Naples, Italy and went on to discover 8 more asteroids.



Deep Sky:

This month let’s go galaxy hunting again, but in the Virgo Cluster.


M87 (Mag 8.6) is the largest elliptical galaxy found in the Virgo Cluster with a super massive black hole in its center. It is about 56 million light years away and spans about 114,000 light years. We can find this galaxy by going to star Vindemiatrix and star hopping about 10 degrees to the right. Messier observed this object in 1781.


M84 (Mag 9.3) is another Virgo Cluster elliptical galaxy found just a degree away to the right from M87. It is about 56 million light years away and has spans at least 81,000 light years. Messier observed it in 1781.


M86 (Mag 9.2) is another Virgo Cluster elliptical galaxy found just a degree away to the right from M87. It is about 56 million light years away and spans at least 114,000 light years. Messier observed it in 1781.


Both M84 & M86 can be seen in a single eyepiece view as they are only 15’ apart. Galaxy NGC 4388 is also nearby and about half as bright, forming a triangle with the others. All three can be seen in the same eyepiece view.




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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