Night Sky Viewing for October 2009
Deep Sky Objects and Constellations to Observe This Month
Sep 23, 2009
The days are getting shorter now that fall is here, which means dark skies appear earlier. This is good news for sky watchers in search of deep sky objects or constellations to observe with the naked eye, binoculars or a small to medium sized telescope.
October offers a shift in night sky objects as the stars of fall move into place leaving the summer sky behind.
Globular Cluster M15 in the Pegasus Constellation
Looking towards the south, this globular cluster lies just to the upper right of Enif, the giant and brightest star in the Pegasus constellation. Pegasus is the big square shaped constellation found just overhead in October. M15 is mostly beyond the naked eye range, but it can be easily spotted with binoculars as an elliptical ball of light.
With a small telescope it looks even better as many stars become visible, especially those in the outer edges. It has a very bright center as many of its stars fall to the center due to a process called 'core collapse'.
The Beautiful Bright Star Fomalhaut
Fomalhaut is a while main sequence star in the Piscis Austrinus constellation and it is the brightest in that group. It can be spotted this month by looking towards the low southern horizon.
A fairly young star, Fomalhaut is about 300 million years old and it lies about 25 light years away. The star is actually surrounded by a huge disc of cool material that is about five times as big as the Solar System.
This disc is really a doughnut shaped ring that has given hints of having big planets around it because of distortions that may be caused by their gravity pull.
Polaris and Ursa Minor
Also known as the Little Dipper, Ursa Minor is always visible from the northern hemisphere and it famously resembles its older sibling's shape, The Big Dipper. To locate it one must look to the north and simply find the distinctive dipper shape, which starts with the ever faithful North Star.
The North Star is at the end of Ursa Minor's 'handle' and it is called Polaris, it lies almost on the fixed point in the celestial pole where all other stars seem to rotate around due to the Earth's spin.
Polaris is actually a multiple star, which consists of a bright yellow Supergiant, about 450 times brighter than the Sun, along with a sun-like star as its companion. Then, there is a much smaller faint dwarf star that is orbiting around it.
The Aquarius Constellation
Aquarius is also known as the Water Carrier and it can be found in the southern sky in October right above Fomalhaut. Within the constellation are a few notable deep sky objects that can be observed; one of them being the Saturn Nebula.
The Saturn Nebula is found on the western edge of Aquarius when looking south. It can be easily spotted with a small telescope appearing as a hazy turquoise ellipse.
In the middle of the nebula lies a red giant that is in the midst of a transition to becoming a white dwarf. With larger telescopes the structure of the nebula becomes more apparent making it resemble the planet Saturn's rings.
Also within Aquarius are a globular cluster, another nebula, a couple of giant stars and a multiple star.
The Omega Nebula M17
This nebula is also known as the Swan or Horseshoe Nebula and it is located in the Sagittarius constellation. It can be found just right of Sagittarius by looking low on the southwestern sky, just above the ecliptic line, in early night October, about 8:00pm.
It can also be located by looking southwest from the bright star Altair, which is in the Aquila constellation in the southwestern sky
The nebula is reddish in color with some pinkish graduations. The color comes from the hot hydrogen gas interacting with the hottest new stars that have just formed. The Omega nebula can actually be seen with the naked eye under good observing conditions and from a dark location.
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