Saturday 07/03/10 Black Star Canyon star party
By: Steve Short
June 30, 2010 3:12AM PDT
Views: 3722

BSC - Saturday 03 July 2010
Hello Fellow OCA club members!

This Saturday I plan to open the gate about 7:30 pm, over a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will be sunny, warm (45% humidity) and clear.  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 (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.
The ISS (International Space Station) will not make any visible evening passes this Saturday but the HST (Hubble Space Telescope) will pass over  twice. The Mag 1.5 first pass will start at 8:35:45 pm 10 degrees high WSW going to 40 degrees high at 8:39:45 South and then dropping to 10 degrees ESE at 8:43:48. The second Mag 2.4 pass will start at 10:17:29 pm WSW going to 24 degrees high SW at 10:19:54 where it will drop out of sight.  There will  be one visible Iridium flare this Saturday at BSC, 11:06:43 pm just 12 degrees high WSW (245 degrees) from Iridium Satellite 49 going from a magnitude -2 to -6.  I am sure we will also see a few dim satellites pass over as we are looking up in the sky but we will not see the secret USAF X-37B space plane I mentioned last month as it will only be visible in early morning passes.

~Mercury, (Mag -1.9) sets about 8:20 pm so will be hard to see this Saturday evening. It is about 123 million miles from Earth in constellation Gemini. Mercury will only be about 5 degrees above the horizon 30 minutes before sunset this month.
~Venus, (Mag -3.9) will dominate the sky after the sun sets and can be spotted  high in the West in constellation Leo. It will not set until about 10:30 pm and is now about 100 million miles from our planet and getting closer. The Venus phase will be about 70% lit diminishing to less than 60% by month end when it will have a 20” diameter disk. On July 9th, Venus will be just 1 degree north of bright 1st magnitude star Regulus.
~Mars, (Mag 1.3) is now in Constellation Leo so will be seen high in the sky this Saturday evening at BSC.  It is about 146 million miles away, getting further every day and is only a small 5” disk. Mars sets about 11:40 pm so will be visible all evening at BSC but is too far away to see any detail on the planet.

~Jupiter, (Mag -2.3) rises just after midnight in constellation Pisces so the big planet will not be seen this month from BSC. It now is about 443 million miles from Earth and getting a little closer every day.

~Saturn, (Mag 1.1) does not set until just after midnight Saturday in constellation Virgo so will  be visible all evening at BSC. Saturn is about 898 million miles away slowly moving further from Earth. Saturn is 15 degrees from Mars but will be about 2 degrees away at month end. The rings tilt about  3 degrees to our line of sight but they will open again this summer and tilt 10% by year end. Saturday evening moon Rhea will be furthest to the east of Saturn with Titan, Dione & Enceladus clustered near the planet. Only moon Tethys will be on the west side.

~ Uranus, (Mag 5.8) will rise just after midnight in constellation Pisces this week and be just 2 degrees from Jupiter so both planets can be seen in the same binocular view. But we will not see this planet at BSC Saturday as we close at midnight. When we can see this planet, it shows up as a 3.6” blue-green disc in a telescope. It is about 1.853 billion miles away moving closer to Earth.

~ Neptune, (Mag 7.9) is in constellation Aquarius, about 2.730 billion miles away this week slowly moving closer to Earth  It is seen as a bluish disc in a telescope and we can finally see it at BSC this Saturday evening as it rises just before 11 pm.


The Delta Aquarids meteor shower peaks before dawn July 28 but a full moon will drown out all but the brightest meteors.  The  radiant is in Aquarius about 10 degrees above bright star Fomalhaut. The meteors come from particles left by the breakup of the Marsden and Kracht sungrazing comets.


Comet C/2009 R1 McNaught (Mag 4.6) is in constellation Auriga and is about 118 million miles from Earth. We might be able to see this comet as the sun sets, half way between Pollux/Castor and  Capella. It was discovered by Rob McNaught September 9th, 2009 in Australia who discovered over 50 comets.

Comet 10P Tempel 2 (Mag 8.3) is in constellation Aquarius just 10 degrees below Jupiter so will not be seen at BSC. It is just 72 million miles from Earth and has a period of 5.37 years.


Minor Planet 1 Ceres (Mag 8.3) can be found in constellation Ophiuchus about 13 degrees above the Scorpion stinger stars.  It is about 172 million miles from Earth and has a period of 4.60 years.

Minor Planet 4 Vesta (Mag 7.9) is the 2nd 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 body,  about 5 degrees above and to the left of Mars. It is now is about 234 million miles from Earth and has a period of 3.63 years.

Deep Sky:

This month, lets look at some globular star clusters in the Scorpion:

M4 (Mag 5.9) is a globular cluster called the “Cat’s Eye” about 14,000 light years away with a diameter of 107 light years. It is found just one degree west of bright star Antares and is estimated to be over 10 billion years old.  Messier observed and catalogued this object in 1764 as a group of very faint stars.

M80  (Mag 7.3) is a globular cluster about 33,000 light years away with a diameter of  86 light years. It forms the apex of a shallow isosceles triangle with Antares & Delta Scorpii and is just a few degrees above M4.  Messier  observed and catalogued this object in 1781.
M19 (Mag 6.8) is another globular cluster about 28,000 light years away with a diamater of 110 light years. It is found about 9 degrees left of M4 and forms the apex of an equilateral triangle using Antares and Epsilon Scorpii as a base. Messier found and catalogued this object in mid 1764.

M62 (Mag 6.5) is a globular cluster about 22,000 light years away with a diameter of 90 light years. It is found just 4 degrees below M19 and both can be seen in a 5 degree binocular field of view. Messier  first observed this object in 1771 but didn’t catalog it until 1779.

 Don't forget to bring your gloves, coats & sweaters because it might 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 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.
Your OCA star party host,


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