Saturday June 20th Black Star Canyon star party
By: Steve & Bonnie Short
June 17, 2015 2:51AM PDT
Views: 2316


Black Star Canyon Star Party notice - Saturday June 20th, 2015


Hello Fellow OCA club members!


This Saturday, we plan to open the gate around 7:30 pm, which is about a half hour before the sun sets. The weather report for this Saturday indicates that Orange County should be warm (89F), have clear skies and humidity near 35%.  But please keep an eye on the OCA website “Home” page (below the next speaker info) where we will post a notice should the star party be canceled for any reason.


We will be between a new Moon & 3rd Quarter so our star party should have a very dark night sky. 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 may 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.

Try to park two cars in each slanted slot between the rock turning circles so we can get 20 cars into that area. I will help guide the first cars into the slots and then expect that others will follow that pattern. The first car in each slot must stay back, about a foot, from the road that leads out of the parking area so cars that leave early with headlights off will not accidentally bump into parked cars

The BSC star party site has a Latitude of 33.7520N, Longitude 117.6745W and Elevation 297'.


Warning:  No Pets allowed!  (This is an OC Parks and Nature Conservancy rule).



  The ISS (International Space Station) will make one magnitude -1.1 visible pass Saturday evening starting at 10:02:02 pm 10 degrees high in the west going to 16 degrees high SW at 10:04:11 pm where it will pass into the Earth's shadow and fade from sight. Look for it just after 10 pm passing along side of Venus and then Jupiter and then right next to the New Moon.

  The X-37B (Air Force Boeing space plane) will not make any visible passes as it has landed.

  The HST (Hubble Space Telescope) will make it's first visible magnitude 1.5 pass Saturday evening starting at 8:26:21 pm 10 degrees high WSW going to 36 degrees high S at 8:30:12 pm and then dropping back to 10 degrees high ESE at 8:34:03 pm. The second visible magnitude 1.8 pass will start at 10:07:20 10 degrees high WSW going to 33 degrees high SW at 8:10:21 then dropping out of sight in Earth's shadow.

  Iridium flares: There will be one magnitude 0.5 visible Iridium Flare this Saturday evening at 8:53:37 pm 17 degrees high NNW (342 degrees) from Iridium Satellite 25. I am sure we will also see a number of satellites pass over in the early evening.


Planets & Pluto:

~Mercury, (Mag 1.0) sets about 6:10 pm in constellation Taurus this Saturday evening so cannot be seen at the BSC star party. Mercury will be about 71 million miles from Earth and rises about 4:30 am so could be seen early in the morning. Mercury reaches greatest elongation June 26th when it is 22 degrees west of the Sun. It will have a disk that spans 8” and be about 34% lit. Look for Mercury just 2 degrees from bright Taurus star Aldebaran June 24th.

~Venus, (Mag -4.4) can be seen 30 minutes before sunset Saturday evening and it sets just before 11 pm in constellation Cancer. Venus will be about 56 million miles from Earth with a disc size of 28” and 42% lit. Look for it 5 degrees above the waxing Moon.

~Mars, (Mag 1.9) will be in Constellation Taurus and on the far side of the Sun from Earth so will not be seen again until late summer. It will be about 240 million miles from Earth Saturday evening.

~Jupiter, (Mag -1.6) will be just below Venus Saturday evening with the Moon just below Jupiter. It will be about 555 million miles from Earth getting a little farther every day with a diameter of about 36”. Look for Jupiter in front of Leo the Lion's head and it will not set until 11 pm. At 8:45 pm we should see moon Callisto far east of Jupiter while moon Europa will be much closer to the big planet. Next will be moon Io just west of Jupiter with big Moon Ganymede much farther west.

~Saturn, (Mag 0.9) will be in constellation Libra this Saturday so should be seen after sunset as it rises about 5:30 pm. It has a disk measuring 18” with rings spanning 42” and tilting 24 degrees. Saturn will be about 846 million miles away Saturday evening and will not set until 4 am. Saturn will be just in front and above of the Scorpion's 3-star head.

 Uranus, (Mag 5.9) will be in constellation Pisces this Saturday evening setting about 2:30 pm so will not be seen at the BSC star party. It shows up as a small 3.4” blue-green disc in a telescope. Uranus will be about 1.891 billion miles from Earth this Saturday. It can be seen in the early morning sky after it rises about 2 am.

Neptune, (Mag 7.9) is in constellation Aquarius, about 2.754 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 see it at BSC this Saturday evening as it does not rise until midnight. It can be seen after midnight until sunrise.

 Pluto, (Mag 14.1) will rise in constellation Sagittarius about 11 pm so could be seen Saturday evening. It is about 2.968 billion miles from Earth and is so dim, you would need a 10” or larger telescope to see it visually. Pluto does not set until 7 am.


There are no major meteor showers in June but the minor Bootid meteor shower is active from June 22 – July 2 peaking June 27th. These meteors hit Earth at only 11 miles per second,the slowest of any shower. Not much activity is expected this year and the maximum rate is highly variable. The radiant is high above Bootes, 25 degrees from bright star Arcturus. We always see a few stray meteors during every BSC star party.

If you ever wanted to do some real scientific meteor counting, the International Meteor Organization (IMO) always needs more observers. You will need to follow the IMO's standards so your counts will be meaningful. See for more information.

Brightest visible Comets:

All the comets in the sky are very dim again this month, but the brightest one that is visible Saturday evening is Comet Lovejoy.

Comet C/2014 Q2 Lovejoy is a magnitude 8.5 (according to the Heavens-above website) and will be 228 million miles from Earth Saturday in constellation Ursa Minor. It has passed by Polaris and is heading directly towards the other magnitude 2 star in the Little Dipper, the end bucket star. It is about 2/3 of the way there.

This comet was discovered on August 17th, 2014 by amateur astronomer Terry Lovejoy from Brisbane, Australia, his 5th discovery. It now looks to have a period of 13,280 years.

Brightest visible asteroids:

Finding an asteroid at the BSC star party is always very challenging as they are dim and are just small dots.

Minor Planet 4 Vesta (Mag 7.7), the 2nd most massive object in the asteroid belt is the brightest asteroid again this month. It would be found in constellation Pisces this month, just below the Ecliptic. Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 203 million miles from Earth at this time and has an orbit period of 3.63 years. It will not be seen Saturday evening as would not be visible until about midnight. NASA’s Dawn spacecraft was in orbit around this asteroid and sent back stunning close-up pictures.


Minor Planet 1 Ceres (Mag 8.0) is the biggest object in the asteroid belt with a diameter of about 590 miles. It is in constellation Capricornus just 10 degrees below the Ecliptic near the bottom of the Goat. It will be about 193 million miles from Earth Saturday and has a period of 4.61 years. It was discovered in 1801 and for 50 years was classified as the 8th planet. But don’t expect to see anything more than a small dot. It will be visible Saturday evening starting about 10 pm. The Dawn spacecraft has reached this asteroid and will be orbiting it taking pictures for at least a year.

Asteroid 2 Pallas (Mag 9.4) is the second asteroid to have been discovered (after Ceres), and one of the largest in the Solar System. It will be in constellation Hercules Saturday evening so visible all evening long. This asteroid has a diameter of about 338 miles and is about 226 million miles from Earth. When Pallas was discovered by astronomer Heinrich Wilhelm Matthaus Olbers on March 28, 1802, it was counted as a planet, as were other asteroids in the early 19th century. The discovery of many more asteroids after 1845 eventually led to their re-classification. It has an orbit period of 4.62 years and the path it is taking is shown in the June Astronomy Magazine on page 43. It will become visible at sunset so might be seen at the BSC star party.

Deep Sky:

This month let’s consider looking at some globular clusters in the Scorpion:

M4 is a magnitude 3.1 globular star cluster, known as the “Cat's Eye” as it looks like a bit like the eye of a cat. It is in constellation Scorpius, is about 14,000 light years away and spans 107 light years. You can find it about one degree west of bright star Antares. Its age is estimated to be 10 billion years old and has a looser compactness than average. Messier observed this object in 1764 and logged it on May 8th.


M80 is a magnitude 7.3 globular star cluster in constellation Scorpius. It is about 33,000 light years away and spans 86 light years. You can find it just above and about half way between bright stars Antares and the center star of the Scorpion's 3 star head. This is a very tight cluster of well over 100,000 stars. Messier observed this object in 1781 and logged it on January 4th.


NGC 6144 is a 10th magnitude globular star cluster in constellation Scorpius, about 33,000 light years away and spans 24 light years. It is a very large cluster of small stars in a very tight cluster. You can find it just north of bright star Antares and its brighter famous neighbor, M4. William Herschel discovered this object in 1785 with an 18.7-inch F/13 scope. .



Don't forget to bring your gloves, coats & sweaters as it can get cold after the sun sets and even colder 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,


| Search