Astronomical Observing at Fishcreek - Friday 9/12/2008 Sunset 7:42pm Civil twilight ends: 8:07pm ( When the Sun is 6 degrees below the horizon ) Nautical twilight ends: 8:40pm ( When the Sun is 12 degrees below the horizon ) Astronomical twilight ends: 9:13pm ( When the Sun is 18 degrees below the horizon ) Tonight's event will be somewhat limited by the nearly full Moon the entire night. Despite the brightness of the moon, we will be able to see Jupiter, colorful double stars, open clusters made up of hundreds of stars, globular clusters comprised of hundreds of thousands of stars, planetary nebula formed by dying stars, diffuse nebula and emission nebula where stars are being born, and galaxies. Jupiter, the King of the planets, is a beautiful sight. With a high-power view through the telescopes, details in the cloud bands is possible, and the four Galilean moons actually appear as disks instead of just point light sources. Uranus and Neptune are visible now as well and appear as small bluish-green 'large' stars in our telescopes. And, for a special treat, we'll be able to watch the Moon occulting Neptune at 8:43:36pm tonight and reemerge from the bright side at 9:48:05pm. How better to actually observe the solar system behaving as it has for eons? We hope to see you here for a night under the stars - now in our thirteenth year! Summary data for 9/12/2008 at 8:39:36pm EDT (nautical twilight) for our location: Longitude: W 81°25' 37.4" Latitude: N 41°11'11.2" Altitude: 350m Above Horizon: Object Mag Const Rise Set Jupiter -2.4 Sgr 16:12 01:29 Uranus 5.7 Aqr 19:32 07:11 Neptune 7.8 Cap 18:20 04:47 Pluto 14.2 Sgr 14:47 00:52 Moon -12.0 Cap 18:17 05:06 Below Horizon: Object Mag Const Rise Set Sun -26.7 Leo 07:00 19:42 Mercury 0.2 Vir 09:22 20:28 Venus -3.9 Vir 09:11 20:43 Mars 1.7 Vir 09:10 20:40 Saturn 0.9 Leo 06:23 19:31 New moon: Aug 1 2008 6:13 Aug 30 2008 15:58 Sep 29 2008 4:12 First quarter: Aug 8 2008 16:20 Sep 7 2008 10:04 Oct 7 2008 5:04 Full moon: Aug 16 2008 17:17 Sep 15 2008 5:13 Oct 14 2008 16:02 Last quarter: Aug 23 2008 19:50 Sep 22 2008 1:05 Oct 21 2008 7:55 Sun data: Rise 7:00am Transit: 1:21pm (Time of highest position in the sky, due South) Sets 7:42pm Constellation: Leo Distance: 1.00614183 AU = 150,516,675 km = 93,526,727 miles = 8.38 light-minutes Magnitude: -26.7 Apparent size: 31.79 arcminutes in angular diameter Civil twilight ends at 8:07pm ( When the Sun is 6 degrees below the horizon ) Nautical twilight ends at 8:40pm ( When the Sun is 12 degrees below the horizon ) Astronomical twilight ends at 9:13pm ( When the Sun is 18 degrees below the horizon ) Fall Equinox: Monday Sept 22, 2008 at 11:45am (when Fall will officially be here) Next Solar Eclipse: Partial eclipse (>80%) on Monday August 21, 2017 2:30pm EDT Next TOTAL Solar Eclipse: Monday April 8, 2024 at 3:15pm On 9/12/2008 at 8:39:36pm the Sun will be 12º below the west horizon Moon data: Rise: 6:17pm Transit: 11:37pm (Time of highest position in the sky, due South) Sets: 5:06am Sept 13 Constellation: Capricornus Phase: 93.88% illuminated (waxing gibbous) 13.20 days since last New Moon Distance: 0.0025821 AU = 386,277 km = 240,021 miles = 1.29 light-seconds Magnitude: -12.0 Apparent size: 30.92 arcminutes in angular diameter Elongation from Sun: 151.28 degrees (evening sky) Next Phase: Full Moon on Monday Sept 15, 2008 at 5:13am Next Lunar eclipse: Total eclipse (100%) on Sunday Sept 27, 2015 at 10:10pm EDT On 9/12/2008 at 8:39:36pm the Moon will be 21.1º above the east-southeast horizon and will look like this. Left image shows Neptune about to be occulted by the Moon. Image on the right shows Neptune re-appearing from the bright side of the Moon a little over an hour later. On 9/12/2008 at 8:39:36pm the Moon will be 21.1º above the east-southeast horizon Mercury data: Rise: 9:22am Transit: 2:55pm (Time of highest position in the sky, due South) Sets: 8:28pm Constellation: Virgo Phase: 53.40% illuminated Distance: 0.92904637 AU = 138,983,359 km = 86,360,257 miles = 7.74 light-minutes Magnitude: 0.2 Apparent size: 7.24 arcseconds in angular diameter Elongation from Sun: 26.79 degrees (evening sky) Next maximum elongations... Morning: Wednesday, October 22, 2008 (18° 19' 05") Evening: Sunday, January 04, 2009 (19° 20' 36") On 9/12/2008 at 8:39:36pm Mercury will be 3.2º below the west-southwest horizon FINISHED (12:05 PM 8/24/2008) Venus data: Rise: 9:11am Transit 2:57pm (Time of highest position in the sky, due South) Set: 8:43pm Constellation: Virgo Phase: 89.79% illuminated Distance: 1.48200898 AU = 221,705,387 km = 137,761,342 miles = 12.34 light-minutes Magnitude: -3.9 Bright, but lost in the glare of the setting sun Apparent size: 11.26 arcseconds in angular diameter Elongation from Sun: 25.84 degrees (evening sky) Next maximum elongations... Evening: Wednesday, January 14, 2009 (47° 07' 21") Morning: Friday, June 05, 2009 (45° 51' 07") On 9/12/2008 at 8:39:36pm Venus will be 0.5º below the west-southwest horizon Mars data: Rise: 9:10am Transit 2:55pm (Time of highest position in the sky, due South) Set: 8:40pm Constellation: Virgo Phase: 98.15% illuminated Distance: 2.44578966 AU = 365,884,926 km = 227,350,356 miles = 20.37 light-minutes Magnitude: 1.7 Apparent size: 3.83 arcseconds in angular diameter Elongation from Sun: 25.30 degrees (evening sky) Next close approach of Mars is on Friday, Jan 29, 2010 On 9/12/2008 at 8:39:36pm Mars will be 0.9º below the west-southwest horizon No, Mars was *not* "...as big as a Full Moon on August 27!" Please see the following links for more information about this annual 'Mars Hoax' http://www.skyandtelescope.com/news/8708182.html http://www.snopes.com/science/mars.asp http://www.hoax-slayer.com/mars-earth-close.html http://www.universetoday.com/2007/07/25/will-the-mars-look-as-big-as-the-moon-on-august-27-nope/ Jupiter data: Rise: 4:12pm Transit 8:50pm (Time of highest position in the sky, due South) Set: 1:29am Sep 13 Constellation: Sagittarius Phase: 99.17% illuminated Distance: 4.6923188 AU = 701,960,901 km = 436,178,287 miles = 39.08 light-minutes Magnitude: -2.4 Apparent size: 42.01 arcseconds in angular diameter Elongation from Sun: 111.96 degrees (evening sky) On 9/12/2008 at 8:39:36pm Jupiter will be 25.6º above the south-southeast horizon Next transit of the Great Red Spot: Tonight at 10:23pm GRS longitude: 125.3° Jupiter satellite events: None tonight Saturn data: Rise: 6:22am Transit 12:57pm (Time of highest position in the sky, due South) Set: 7:31pm Constellation: Leo Phase: 99.99% illuminated Distance: 10.33174395 AU = 1,545,606,896 km = 960,395,612 miles = 1.43 light-hours Magnitude: 0.9 Apparent size: 16.09 arcseconds in angular diameter Elongation from Sun: 7.75 degrees (morning sky) On 9/12/2008 at 8:39:36pm Saturn will be 13.3º below the west-northwest horizon Uranus data: Rise: 7:32pm Transit 1:22am Sep 13 (Time of highest position in the sky, due South) Set: 7:11am Sep 13 Constellation: Aquarius Phase: 100.00% illuminated Distance: 19.09223685 AU = 2,856,157,980 km = 1,774,734,311 miles = 2.65 light-hours Magnitude: 5.7 Apparent size: 3.69 arcseconds in angular diameter Elongation from Sun: 179.19 degrees (morning sky) On 9/12/2008 at 8:39:36pm Uranus will be 11.2º above the east horizon Neptune data: Rise: 6:20pm Transit: 11:34pm (Time of highest position in the sky, due South) Set: 4:47am Sep 13 Constellation: Capricornus Phase: 99.99% illuminated Distance: 29.14865532 AU = 4,360,576,769 km = 2,709,536,820 miles = 4.05 light-hours Magnitude: 7.8 Apparent size: 2.34 arcseconds in angular diameter Elongation from Sun: 151.49 degrees (evening sky) Special note: The unilluminated side of the Moon will occult the 7.8mag planet Neptune at 8:43:36pm tonight! On 9/12/2008 at 8:39:36pm Neptune will be 21.2º above the east-southeast horizon Pluto (Dwarf Planet aka Asteroid 134340) data: Rise: 2:47pm Transit 7:50pm (Time of highest position in the sky, due South) Set: 12:52am Sep 13 Constellation: Sagittarius Phase: 99.97% illuminated Distance: 31.36802367 AU = 4,692,589,549 km = 2,915,839,999 miles = 4.35 light-hours Magnitude: 14.2 Apparent size: 0.11 arcseconds in angular diameter Elongation from Sun: 97.84 degrees (evening sky) On 9/12/2008 at 8:39:36pm Pluto will be 30.3º above the south horizon