Saturday October 20th Black Star Canyon star party
By: Steve & Bonnie Short
October 17, 2012 2:49AM PDT
Views: 2703

BSC Star Party Notice  - Saturday October 20th, 2012


Hello Fellow OCA club members!


This Saturday, I plan to open the gate around 5:45 pm, which is about a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will again be sunny and clear with humidity at 45%.  But 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 crescent Moon will set about 11 pm Saturday. First time visitors might want to get to the star party site 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.

  We will not even get to see any Iridium flares Saturday evening at BSC. But I am sure we will see a few dim satellites pass overhead as we are looking up in the sky.


Planets & Pluto:

~Mercury, (Mag 0.0) sets at 7 pm in constellation Libra but is too low (3-4 degrees) to the horizon this month to make a good target for observations. It is about 110 million miles from Earth at this time.

~Venus, (Mag -3.9) will not be seen Saturday evening as it sets about 4:35 pm in constellation Leo. Venus is now about 109 million miles from Earth and can be seen early morning as it rises at 4 am. On Saturday morning Venus should be 78% lit with a 14” disk.

 ~Mars, (Mag 1.4) is now in Constellation Scorpius so is visible at sunset until setting at 8:20 pm. Mars will be just 3.5” above slightly brighter Antares so this is a good time to compare their famously similar colors. Mars is about 191 million miles away now with a 4.7” disk so none of our scopes should be able to see any detail on the red planet until it is closer.

~Jupiter, (Mag -2.4) will rise about 9 pm in constellation Taurus Saturday evening, so will be up in time for us to observe in a telescope at the star party. It now is about 406 million miles from Earth getting a little closer every day with a diameter of about 45”.  Moon Callisto will be far east of Jupiter with Europa hidden behind the big planet as it gets dark, but will slip into view about an hour later. Moon Io will be west of Jupiter and biggest moon Ganymede just a bit further west.

~Saturn, (Mag 1.1) will be in constellation Virgo this Saturday and sets early at about 6:40 pm. Saturn is about 1 billion miles away slowly moving farther from Earth. It is too close to the Sun for us to view the rest of this month.

~ Uranus, (Mag 5.7) will be in constellation Pisces this Saturday evening rising at 5:30 pm so will be up at sunset. It shows up as a small 3.7” blue-green disc in a telescope. This planet reached opposition on September 29th, when it was opposite the Sun in our sky. It will remain visible from sunset to 5:30 am and glows bigger and brighter than at any other time of the year. It is about 1.778 billion miles away from Earth which is about as close as it gets to our planet.


     Note: The September Sky & Telescope magazine shows the 2012 paths of Uranus and Neptune on page 50.


~ Neptune, (Mag 7.9) is in constellation Aquarius, about 2.734 billion miles away this week slowly moving closer to Earth. It is seen as a bluish gray 2.4” disc in a telescope. We should be able to see it at BSC this Saturday evening (it is bright enough to even be seen through binoculars), as it does not set until 2:45 am.

 ~ Pluto, (Mag 14.1) rises about 12:30 pm so could be seen Saturday evening up to about 10:40 pm when it sets.  It is 3.032 billion miles from Earth in constellation Sagittarius. Since it is so dim, you will probably need a 10” or larger telescope to see it visually. The June 2012 Sky & Telescope magazine shows Pluto’s path for all of 2012 on pages 52-53.  On Saturday, Pluto will be just 3.5 degrees west from the center of M25.



The Orionid Meteor Shower peaks on the 20/21st. The radiant is near Betelgeusein Orion’s “Club” and this Saturday we might see about 20 meteors per hour after the crescent moon sets about 11 pm.


Brightest visible Comets:

This month all the comets orbiting the Sun are very dim so will be extremely difficult to find and see. 


The magnitude 12.6 Comet 168P Hergenrother might be seen Saturday at the BSC star party in constellation Pegasus along the northern leg of the great “Square”. Look for it just 4 degrees west of the Northeastern Pegasus Square star (that is a part of the Andromeda constellation). It is about 45 million miles from Earth at this time.


The magnitude 12.8 Comet C/2011 L4 Panstarrs probably won’t be seen Saturday at the BSC star party in constellation Libra (5 degrees in front of the Scorpion’s head) as it is just too close to the Sun. It is about 329 million miles from Earth at this time. This comet was discovered in June 2011 by a team using the Pan-Starrs telescope on Maui and has a very parabolic orbit. It will approach within 30 million miles of the Sun in early 2013, about the distance Mercury is from the Sun.



Brightest visible asteroids:


Bright asteroids Ceres and Vesta are close to Jupiter this month so can be seen Saturday evening after 10 pm.


Minor Planet 1 Ceres (Mag 9.1) is the biggest object in the asteroid belt with a diameter of about 590 miles. It is in constellation Gemini and can be found about 12 degrees east of Jupiter. It is about 205 million miles from Earth and has a period of 4.61 years. It was discovered in 1801 and for 50 years was classified as the 8th planet. It will be visible Saturday evening after 10 pm so might be seen at the BSC star party. This asteroid will be the next stop for the Dawn spacecraft.



Minor Planet 4 Vesta (Mag 7.5), the 2nd most massive object in the asteroid belt, can be found in constellation Taurus, about 8 degrees east of Jupiter just 2 degrees below the Ecliptic. Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 180 million miles from Earth at this time and has an orbit period of 3.63 years. It will rise about 10 pm so might be seen at the BSC star party. NASA’s Dawn spacecraft was in orbit around this asteroid and sent back stunning close-up pictures.



Deep Sky:

This month let’s consider looking at some Messier Open Star Clusters near Jupiter:


M35 is a magnitude 5.1 open star cluster about 2,800 light years away that spans 23 light years. This cluster contains about 200 stars, the brightest shining at a magnitude 8.2. Its age is estimated to be 110 million years. You can find it in constellation Gemini by following a line from Aldebaran through M1 for about 10 more degrees to M35.


M37 is a magnitude 5.6 open star cluster in Auriga about 4,200 light years away that spans 29 light years. It contains about 150 stars, the brightest shining at a magnitude 9.2. Its age is estimated to be 330 million years.  You can find it along a line made by the top (northern) Tarus the Bull “Horn” about 10 more degrees to M37.


M36 is a magnitude 6.0 open star cluster in Auriga about 3,700 light years away that spans 13 light years. It contains about 60 stars, the brightest shining at a magnitude 8.9. Its age is estimated to be 25 million years. You can find this star cluster about 5 degrees Northwest of M27.






Don't forget to bring your gloves, coats & sweaters in case it gets cold after the sun sets or later as 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 get dark. Please remember to cart off all your trash as there are no garbage cans at BSC. There is also one portable restroom on site should nature call.


Hope to see you there.


Your OCA star party host,


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