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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.
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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.
AstroChallenge: Beta Monocerotis: A True Triple.
This week, we�d like to turn your attention towards an interesting object in an often overlooked constellation; Monceros. Sandwiched between the flashier constellations of Orion and Canis Major, this rambling constellation sports an interesting multiple star that should be part of your spring repertoire; Beta Monocerotis.
This is a true ternary system discovered by Sir William Herschel in 1781. Low power will easily split the AB pair at about 7.4� arc seconds, and a bit of a boost under clear steady skies will split the B-C pair at 2.8� The visual magnitude for the system is +4.6, and the entire system resides about 700 light years distant. The entire system weighs in at about 18 solar masses, and the C component is�suspected but not confirmed to be a double itself!
The Astroterm for this week is the Annual Aberration of Starlight. This term refers to the apparent displacement of stars as a result of our movement about the sun. This curious effect is separate from Parallactic, or true apparent shift that astronomers measure to gain a distance estimate. First noticed in 1725 by�astronomer James Bradley,�this motion gave astronomers a first hint that the speed of light was indeed finite. The annual aberration of starlight is distance independent, meaning that the same value�of displacement is�seen for objects�across the celestial sphere. The analogy often given is the apparent tilted motion of raindrops as you move�forward in the rain; in this case, you are the Earth bound observer, and the rain is the incoming starlight. A smaller diurnal aberration also occurs because of the Earth�s rotation. All of this had to be untangled before astronomers could measure the first true parallax measurements of stars in the mid-19th century. The yearly value for the annual aberration of starlight is 40� in a circular motion for stars inclined 90 degrees to the ecliptic, and linear for those along the ecliptic plane. A system like Beta Monocerotis would exhibit a flattened oval due to this effect if it were carefully plotted over the course of a year.