Saturday July 11th Black Star Canyon star party
By: Steve & Bonnie Short
July 8, 2015 4:29AM PDT
Views: 2126


Black Star Canyon Star Party notice - Saturday July 11th, 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 (80F), have clear skies and humidity near 50%.  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 not make any visible passes Saturday evening at BSC but can be seen making early morning passes.

  The HST (Hubble Space Telescope) will not make any visible passes Saturday evening.

  Iridium flares: There will be one magnitude -3.8 visible Iridium Flare this Saturday evening at 8:59 pm 18 degrees high NNW (344 degrees) from Iridium Satellite 30. I am sure we will also see a number of satellites pass over in the early evening.


Planets & Pluto:

~Mercury, (Mag -0.9) sets about 7 pm in constellation Gemini this Saturday evening so cannot be seen at the BSC star party. Mercury will be about 112 million miles from Earth and rises about 4:50 am so could be seen early in the morning. Mercury reached greatest elongation June 26th when it was 22 degrees west of the Sun. It will have a disk that spans 6” and be about 70% lit. Mercury passes behind the Sun from our view July 23rd.

---Venus & Jupiter made a dazzling conjunction July 1st where they looked less than 1 degree apart.---

~Venus, (Mag -4.4) can be seen 30 minutes before sunset Saturday evening and then sets at 10 pm in constellation Leo. Venus will be about 41 million miles from Earth with a disc size of 40” and 25% lit. Look for it 8 degrees to the lower right of 1st magnitude star Regulus.

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

~Jupiter, (Mag -1.6) will be seen just below Venus Saturday evening. It will be about 575 million miles from Earth getting a little farther every day with a diameter of about 30”. Look for Jupiter in front of Leo the Lion's head and it will not set until almost midnight. At 8:45 pm we should see moon Callisto far west of Jupiter while moon Ganymede will be much closer to the big planet. Next will be moon Io passing in front of Jupiter with Moon Europa off to the east of Jupiter.

~Saturn, (Mag 1.0) will be in constellation Libra this Saturday so should be seen after sunset as it rises about 4 pm. It has a disk measuring 18” with rings spanning 40” and tilting 24 degrees. Saturn will be about 867 million miles away Saturday evening and will not set until 2:30 am. Saturn will be just in front and above of the Scorpion's 3-star head.

 Uranus, (Mag 5.8) will be in constellation Pisces this Saturday evening setting about 1 pm so will not be seen at the BSC star party. It shows up as a small 3.5” blue-green disc in a telescope. Uranus will be about 1.859 billion miles from Earth this Saturday. It can be seen in the early morning sky after it rises about 30 minutes after midnight.

Neptune, (Mag 7.8) is in constellation Aquarius, about 2.725 billion miles away this week slowly moving closer to Earth. It is seen as a bluish gray 2.3” disc in a telescope and might be seen at BSC this Saturday evening after it rises at 10:45 pm. It can be seen until sunrise as does not set until about 10 am.

 Pluto, (Mag 14.1) will rise in constellation Sagittarius about 7:30 pm so could be seen Saturday evening. It is about 2.967 billion miles from Earth and is so dim, you would need a 12” or larger telescope to see it visually. Pluto does not set until 5:30 am. The New Horizons probe will reach Pluto July 14th and the path Pluto & the probe are taking is shown in the July Sky & Telescope Magazine on pages 52-53.


There are no major meteor showers in June but the minor Southern Delta Aquarid meteor shower is active from July 12 – August 3rd peaking July 27th. This shower typically produces 15-20 meteors per hour. The radiant is just above bright star Fomalhaut with meteors seeming to come out of Aquarius. 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 244 million miles from Earth Saturday in constellation Ursa Minor. It has passed by Polaris and the end bucket stars and can be found about a bucket below the “bucket”. 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 13,332 years.

Brightest visible asteroids:

Finding an asteroid is always very challenging as they are dim and are just small dots.

Minor Planet 4 Vesta (Mag 7.5), the 2nd most massive object in the asteroid belt is the brightest asteroid again this month. It would be found in constellation Cetus this month, just below the Ecliptic. Vesta has a diameter of about 330 miles and was discovered in 1807. It is about 182 million miles from Earth at this time and has an orbit period of 3.63 years. It might be seen Saturday evening as would be visible just after 11 p. NASA’s Dawn spacecraft was in orbit around this asteroid and sent back stunning close-up pictures.


Minor Planet 1 Ceres (Mag 7.7) is the biggest object in the asteroid belt with a diameter of about 590 miles. It is in constellation Microscopium just 10 degrees below the Ecliptic near the bottom of the Goat. Ceres will be about 182 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 after sunset. The Dawn spacecraft has reached this asteroid and will be orbiting it taking pictures for at least a year. The path Ceres is taking this month can be seen on page 42 of the July Astronomy Magazine. A better picture of the orbit Ceres is taking up to November is shown on page 50 of the July Sky & Telescope Magazine.

Asteroid 2 Pallas (Mag 9.6) 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 236 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 July 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 3 of the most fabulous globular clusters in the night sky:


M13 is the most famous, a magnitude 5.8 globular star cluster, known as the “Great Hercules Cluster”. It is in constellation Hercules about 21,000 light years away and spans 104 light years. You can find it along two cornerstone stars, about 1/3 of the way down from the most northern, right-side corner star. Its age is estimated to be 14 billion years old and the estimated 500,000 stars have a tighter compactness than average. Messier observed this object in 1764 and logged it on June 1st.


M3 is a magnitude 6.2 globular star cluster in constellation Canes Venatici. It is about 35,000 light years away and spans 165 light years. You can find it about half way between bright star Arcturus and the bright “corner” star of Canes Venatici. The cluster contains about 50,000 stars and its compactness is considered average. Its age is estimated to be 6.5 billion years. Messier observed this object in 1764 and logged it May 3rd.


M5 is a magnitude 5.7 globular star cluster in constellation Serpens, about 26,000 light years away and spans 132 light years. It is slightly oval in shape and the compactness is tighter than average. There is a bright 5th magnitude star 5 Serpentis ½ degree from the cluster. You can find it along a line from Arcturus to Antares, about 1/3 of the way to Antares. Its age is estimated to be 13 billion years. Messier observed this object in 1764 and logged it May 23rd.


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,


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