Saturday 02/26/11 Black Star Canyon star party
By: Steve Short
February 23, 2011 3:54AM PDT
Views: 4011

BSC - Saturday 26th February 2011

Hello Fellow OCA club members!


This Saturday, if not cloudy or raining, I will open the gate about: 5:15 pm, which is about a half hour before the sun sets. The weather report for this Saturday indicates that Orange County will be cloudy with 30% chance of rain. So keep an eye on the OCA website where I will post a  notice on the home page should the star party be cancelled.


If we do have a star party, the 3rd quarter moon will not rise until 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 evening passes this Saturday. But the HST (Hubble Space Telescope) will make two visible passes Saturday evening, with a Mag 2.2 pass starting at 6:33:08 pm 10 degrees high SW moving to 28 degrees high SSE at 6:36 and then dropping to 15 degerees high ESE at 6:39. The second Mag 3.3 pass will start at 8:14:12 pm 10 degrees high WSW moving to 18 degrees high WSW at 8:15 where it will drop out of sight.  There will also be one visible Iridium flare at 6:45 pm 47 degrees high SSE going from a Mag -3 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 -1.4) sets about 5:34 pm behind the sun so will not be seen this Saturday evening or even in the morning for awhile. It is about 129 million miles from Earth in constellation Aquarius.

~Venus, (Mag -4.0) will not be seen Saturday evening as it sets about 2 pm but can be seen in the morning as it rises about 4 am in constellation Sagittarius. It will be very bright and about 70 percent illuminated going from 61% to 71% lit in February while it’s angular diameter will shrink from 20” to 16”. It is now about 95 million miles from Earth.

 ~Mars, (Mag 1.1) is now in Constellation Aquarius setting about 5:21 pm and rises at 6:21 am but is too close to the Sun to be seen this month.  It is about 220 million miles away, still too far away to see any detail on the planet anyway.

~Jupiter, (Mag -1.9) will set about 8:12 pm and is still bright enough that it will become visible in constellation Pisces as the sun sets. It now is about 536 million miles from Earth getting a little further every day. We should still see lots of detail on the big planet early in the evening including the North Equatorial Belt (NEB) and just a thin dark SEB line, since that belt disappeared in 2010. This Saturday, moon Europa will be seen just west of Jupiter while Io will be just East of the big planet, followed by Ganymede and Callisto farthest away.

~Saturn, (Mag 0.5) rises about 9 pm Saturday in constellation Virgo so will  be visible at the BSC star party. Saturn is about 823 million miles away slowly moving closer to Earth. The ringed planet will not set until 8:30 am so can also be seen only in the morning sky this month. The rings will be tilted 10 degrees from edge on so are spectacular, spanning 42”.

~ Uranus, (Mag 5.9) will set at about 7:30 pm this week, about a half hour before Jupiter, in constellation Pisces. It will be about 8 degrees from Jupiter Saturday evening. It shows up as a small 3.4” blue-green disc in a telescope and is about 1.952 billion miles away, moving further from Earth.

~ Neptune, (Mag 8.0) is in constellation Aquarius, about 2.883 billion miles away this week slowly moving farther from Earth  It is seen as a bluish 2.2” disc in a telescope but we will not be able to see it at BSC this Saturday evening as it has slipped behind the sun.


February is a slow month for meteors with no major showers. We normally see a few stray meteors at every BSC star party even when no meteor shower is expected.


Comets: There are no visible comets brighter than magnitude 12 right now.


Brightest visible evening asteroids:

Minor Planet 7 Iris (Mag 8.7) is the 4th brightest object in the asteroid belt with a diameter of about 125 miles. It is in constellation Gemini and can be found this month about half way along an arc from Pollux to Procyon. Iris is about 128 million miles from Earth, getting farther and has a period of 3.68 years. It was J.R. Hind’s first asteroid discovery made on August 13, 1847.


Minor Planet 3 Juno (Mag 9.3) is another big object in the asteroid belt with a diameter of  about 140 miles. It is in constellation Virgo and Juno can be found half way along a line between Regulus and Spica. Juno is about 166 million miles from Earth and has a period of 4.36 years. It was discovered in 1804.


Minor Planet 20 Massalia (Mag 9.4) can be found in constellation Virgo near Juno along the same line but just a few degrees further away from Regulus. Massalia has a diameter of about 90 miles and was discovered in 1852. It is about 112 million miles from Earth and has a period of 3.74 years.


Deep Sky:

This month, lets look at some open clusters in Taurus:


NGC 1647 (Mag  6.4) is an open cluster found atop the Bull’s head. It is about 1,790 light years away and has a span of about 45’. It contains about 200 loosely scattered stars with the brightest having a magnitude of 8.4. It has an age estimated to be 100 million years old and Herschel discovered this object in 1784.


NGC 1764 (Mag  6.1) is an open cluster found between the Bull’s horns. It  has a span of about 40 arc minutes. This object was discovered by Herschel as NGC 1750 in 1758 and rediscovered as NGC 1764 in 1863 by d’Arrest. It is about 2,500 light years away and has red stars indicating it is very old.


NGC 1802  (Mag 7.7) is an open cluster found between the Bull’s horns just a few degrees from NGC 1764. It was discovered in 1785 by William Herschel and is thought to be 1,300 light years away. There is a double star (Pou 569) in this cluster.


Don't forget to bring your gloves, coats & sweaters because it will get even colder 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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