Astronomy From Your Back Yard - 8/25 to 8/30 2010
Thursday, August 26 2010 @ 01:42 pm EDT
Contributed by: dgrosvold
By Dave Grosvold
With the Moon just past full this weekend, much of the deep sky will be difficult to observe, and the Moon itself is so bright that much of the detail will be lost in the glare. However, that doesn't mean we have to throw in the towel and stay indoors. There are plenty of celestial targets still available for summer observing.
Jupiter rises well below the Moon about an hour after dark. Although they look close together, Jupiter will be 1,500 times farther from us than the Moon is when they pass on the 26th and 27th. A small telescope or larger binoculars will reveal Jupiter's Galilean Moons. The positions of these moons change from night to night, so a planetarium program or online Galilean Moon Graph utility is essential for identifying these four Jovian satellites.
Uranus is only about 2° west of Jupiter. In a telescope Uranus is only 3.7 arcseconds wide, compared to Jupiter's unusually wide 48 arcminutes. Uranus can be hard to spot. Look for a greenish-white object that is slightly more disk-like than the surrounding stars.
Beginning mid-week, look low in the west-southwest during twilight. Here, Venus forms the bottom of an upside down flat, symmetrical triangle with much fainter Mars and Spica a little higher. By now, Saturn has moved far off to Venus' right or lower right. By Monday, the Venus-Spica-Mars triangle distorts significantly as Venus moves closer to Spica.
Don't forget as well that although the Moon is bright and the deep sky is washed out, The International Space Station still presents a bright target for night sky observers. On Wednesday at 8:30 PM CDT, the ISS should pass high overhead in the SE at an altitude of 50°, shining brightly at magnitude -3.4. The ISS makes several more passes this week, though none is as bright as this one.
On Thursday, look for the ISS at 8:57 PM CDT, as it passes a little less than halfway up the sky (34°) in the NW, reaching magnitude -1.9. On Saturday evening, look for it at 8:17 PM CDT, this time just a bit lower in the NW at altitude 29°. The ISS will shine a bit less brightly at magnitude -1.5. The ISS passes overhead just about every night this week, but these are the brightest.
Also this week, Iridium 3 flares to magnitude -2 in the early morning hours on Friday at 5:21 AM CDT. Look for the Iridium 3 flare at an altitude of 52° in the SW. Iridium 76 flares to a stunning magnitude -8 early on Saturday morning at 5:15 AM CDT, also at 52° altitude in the SW. Sunday evening, Iridium 7 will flare to magnitude -1 at 9:37 PM CDT. Look for it low on the northern horizon at an altitude of 12°. Check the charts at Heavens Above to find out when and which direction to look to catch the both the ISS and Iridium Flares.