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[...] Perseid meteor shower is the most well-known and dependable shower of the year; typically, 60 to 100 meteors are seen, [...]
The Sky is Waiting.
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Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.
The Algonquin Indians had names for each of the seasonal Full Moons, many of which survive today. The Full Snow Moon pictured occurs in the month of December, when the first large winter storms coat the ground with snow. This Full Moon also tends to fall near the Winter Solstice, and thus rides high in the nightly sky opposite to the Sun on long winter nights.
Every rocket launch is unique, but twilight shuttle launches where by far the most impressive. The image pictured was of the April 5th, 2010 launch of Space Shuttle Discovery from the Kennedy Space Center at dawn. The exhaust plume caught the rising Sun overhead just right, and numerous noctilucent clouds persisted right up until sunrise. Unfortunately, space shuttle launches are now relegated to the pages of history.
10.8.9: Will the Perseids Perform?
Are we in for a Perseid spike? (Credit: NASA/Spaceweather).
Set your alarm clocks; one of the best meteor showers of the year is about to gear up this week! The Perseid meteors are one of the most dependable annual showers of the summer season, with a typical zenithal hourly rate (ZHR) of up towards 60-100 per hour. This year however, we could be in for a treat; there is evidence that we may intercept a fresh stream shed by progenitor comet Swift-Tuttle in 1610. We have never passed through this particular stream before; predictions are trending towards a brief ZHR of up towards 200! Don’t forget, however, that ZHR is optimal; this assumes the radiant is directly overhead and that there is no light pollution. The shower peaks morning of Wednesday August 12th, although it would be worth it to peek at the sky a few days prior to see what we might be in for. This year, the timing actually favors the North American continent! Now for the bad news; the waning gibbous Moon will be rising just before midnight in the constellation Aries, and be about 63% illuminated. If this is your chief source of light pollution, try to position yourself for observing in a way that blocks the Moon behind a hill, peak of a roof, whatever is handy. The Perseids are a true treat because they occur in the northern hemisphere summer, when its generally pleasant to lay outside. And school’s still out, to boot! Be sure not to miss this one; the only observing equipment you need is your eyes. If you can convince a friend to observe with you in the wee hours, you can collectively cover more sky. The radiant is located in the constellation Perseus (hence the name) which will be high in the north east. And don’t forget the bug spray!
The astro-term for this week is meteor stream. All meteors originate from a parent comet, or very rarely, an asteroid. Even the largest fireball you see in a given meteor shower is probably not larger than a pea, and most meteor streaks are caused by mere dust grains. These grains are dispersed along the orbit of the comet that shed them, and if that path intersects Earth’s, a shower occurs. Meteor streams evolve over time; some are pretty evenly distributed, while others like the Leonids tend to be clumpy. Only in the last decade or so has the modeling of meteor streams approached effective prediction of what we see in reality. And don’t forget, the front wind shield of the car gets the bug splatter, meaning that you’ll see many more meteors in the early AM!