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[...] you too will get bitten by the ‘quasar bug,’ and hunt for crosses,microquasars, BL Lacertae objects, Seyfert galaxies and more. The February 12th 2020 occultation of quasar 3C [...]
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.
Astro-Challenge: Spy a Microquasar.
So, you’ve seen everything the night sky has to offer? You say you’ve seen all breeds of eclipses and deep sky objects, and have grown tired of showing the neighbors Saturn and the Ring Nebula? Well, we’ve got a challenge for you. This week’s object will require dark skies, a good finder chart, and a generous aperture telescope. About 4 degrees northwest of the 3rd magnitude star Delta Aquilae lies +14.1 magnitude SS 433.
At about the same brightness as Pluto, this star like point amid a star rich field belies its truly amazing nature. Discovered in 1977 by Sanduleak and Stephenson during a routine survey, something was immediately noticed as odd about the system; spectral shifts were alternately blue and red shifted, to a degree of about 16% the speed of light. The system was also embedded in the supernova remnant W50, and clearly located within our galaxy about an estimated 18,000 light years distant. The system is also the source of a copious amount of X-rays… just what could create a star that’s both coming and going? Astrophysicists believe that SS 433 is a microquasar, one of the first ever discovered. The pair consists an 11 solar mass type A star orbiting either a neutron star, or more than likely, a black hole. The simultaneous motion is due to alternating jets of matter streaming away and towards us from the poles. How can anything escape a black hole? Well, don’t forget that while the black hole may be collapsed to an infinitely small point, it still retains its signature mass; the Schwarzschild radius merely defines the region within which the escape velocity exceeds the speed of light… beyond those bounds, escape is still fair game. The polar jets are inclined about 79 degrees to our line of sight, and the relativistic jets precess over a period of about 163 days. The system is a radio and x-ray eclipsing binary, and has been much studied by the Chandra and Arecibo telescopes due to its proximity compared to extra-galactic quasars. Of course, don’t expect SS 433 to look like anything more than a faint star; this is one of those challenges where knowing the true nature of what you’re looking at is part of the fun. The AAVSO has excellent finder charts and the position of SS 433 is;
R.A.: 19H 11’ 50”
Dec: +04 58’ 58”
Good Luck!
This week’s Astroword is, you guessed it, Microquasar. A microquasar shares the same characteristics of their more massive extragalactic cousins, namely a large accretion disk surrounding an ultra-compact massive object accompanied by relativistic radio and x-ray jets. But while traditional quasars house sources in the millions of solar mass variety and can be seen half way across our galaxy, microquasars contain black holes of the stellar mass variety and are known to exist within our galaxy. SS 433 was the first such beastie discovered, and other known microquasars included GRS 1915+105 and the infamous (cue Rush music) Cygnus X-1. Microquasars are sometimes also interchangeably known as radio-jet x-ray binaries.