Sept. 2014 Constellation of the Month - Sagittarius

We can use our either our July constellation of the month -- the Summer Triangle --  or our August constellation -- Scorpius --  to find our September constellation of the month – Sagittarius.  The Summer Triangle points south to a spot just east of the teapot-shaped Sagittarius, which, in turn, is just east of Scorpius.  Sagittarius is easy to recognize, being compact in shape and comprised of moderately bright stars.

Sagittarius is unique in at least one respect: when you look in the direction of Sagittarius, you are looking toward the center of our Milky Way Galaxy.  Not surprisingly, the band of the Milky Way appears brightest in that direction.  

The center of our galaxy is about 27,000 light years from the Earth – or 27,000 times 6 trillion miles.  At the center is a super-huge black hole with a mass of about 4 million of our Suns.  It is constantly adding to its mass by sucking in everything which is "nearby" by astronomical standards, including stars, nebulae and other black holes.

 

 Sagittarius has several nebulae and star clusters which can be seen in small telescopes, such as those we use in Discovery Center astronomy events.  The most famous of these are the spectacular Lagoon Nebula (below), the Omega Nebula and the Trifid Nebula.

 
 

The DC Women's Hiking Group will hike Tues., Sept. 2nd and Thurs., Sept. 4th at
Saugatuck Falls Natural Area in Redding, CT.
The entrance is located between
mail box # 65 and 73 on Diamond Hill Road in Redding. Follow
straight in until you see the large sign (entrance marker) on your left.
Meet at 8:30am.

The Green Corn Supermoon

For those who missed the July 12 rendition of a supermoon, your second chance is coming up.  It will happen on Sunday, Aug. 10^th at 2:09PM ET.  It will continue to look “super” throughout Sunday evening and into early Monday morning.  This will be the largest and brightest moon of the year.  A supermoon occurs when the moon becomes full on the same days as its perigee, when it is closest to the earth in its orbit.  In his case a mere 221,796 miles away.  This is a fairly common occurrence but it does make for a good “Moon Media Event”.   This month’s moon will appear 12% bigger and 30% brighter than the January 2014 event.  However, it is not the brightest of the supermoons.  That occurred on March 19, 2011 at 14% bigger; a fullness that won’t occur again till 2030.  However, to the casual observer, it is hard to tell this minor difference.   To view a supermoon for its maximum effect, look to the distant horizon making sure you have objects such as mountains or buildings in the foreground.  As the moon rises behind these objects, it creates an optical illusion, which makes it look even larger to the naked eye.  Don’t worry if you miss it, the moon will appear full for several more days.  However, if you miss it all together, the next supermoon will occur on Sept. 28, 2015. Enjoy the night sky! (Photo by David Haworth - Nightskyinfo.com)

July 2014 Constellation of the Month – The Summer Triangle

Our July 2014 Constellation of the Month is not one of the official 88 constellations, but it is nonetheless a prominent and memorable shape made by stars.  The Summer Triangle is comprised of the brightest stars of 3 constellations.  You can't miss them; they are the brightest stars in the East an hour or two after sunset, about midway between the eastern horizon and overhead.

The brightest of the 3 stars – Vega, in the constellation of Lyra (the Harp) – is the easternmost one.   To the west and north is Deneb, in the constellation Cygnus (the Swan, also known as the Northern Cross).  To the west and south of Vega is Altair in the constellation Aquila, the Eagle. 

The Summer Triangle is a good non-constellation star pattern ("asterism") to get to know.  (Asterisms can also be well-known parts of constellations, e.g.,  the Big Dipper is a part of the constellation Ursa Major).   The Summer Triangle is visible about half the year, and it can be useful as a starting point for finding other constellations -- as we'll describe in coming months.

Vega is an important star, because it was used to define the zero point in the scale used to specify the apparent brightness of stars – the magnitude.  I say "apparent" brightness, because it describes how bright a star appears to us on earth.  A very bright star (one with a large "absolute" brightness) which is very far away can appear to us as less bright than a star of average brightness which is much closer to earth.  "Close" in astronomical terms, could be 50  trillion miles away.

So, Vega was defined as having a magnitude of 0.  And the brightness of other stars was measured in relation to that.  In order to avoid very large numbers, the magnitude scale is logarithmic, like the Richter scale for earthquake intensity.  A magnitude 1 star is 2.5 times as bright as a magnitude 0 star.  And a magnitude 2 star is 2.5 times fainter than that.  So a magnitude 2 star is 2.5 x 2.5 (6.25) times fainter than a magnitude 0 star. 

Stars brighter than 1.5 magnitude are called 1^st magnitude, from 1.5 – 2.5 are 2^nd magnitude and so on.  The naked eye in Ridgefield can probably see no fainter  than 4^th magnitude, due to light pollution. The other two stars in the Summer Triangle – Altair and Deneb – are magnitudes 0.77 and 1.2, respectively.  So they are also 1^st magnitude stars.  By way of comparison, the stars in the Big Dipper are magnitude 2 stars. 

Be Prepared!

Sturges Park came alive with 14 third and fourth grade Club Scouts as they learned how to "Be Prepared" in the outdoors.  Part of their training involved learning the 10 essential items to pack for a day hike, why "cotton is rotten", and how synthetics and wool are better, especially when worn in layers.  After decorating hiking sticks, they went off on an adventure in the woodlands.  Learning trail blazes was secondary to being prepared for anything that might be lurking among the trees.  Maybe a bear or wolf would jump out at any moment!  They were all in agreement that their new hiking stick could be used as a defensive weapon and not just a helpful balancing tool.  Disappointingly, only two toads and a very large snail were sighted.  They went on to learn the “Rule of Threes for Survival” which is in any extreme situation one cannot survive 3 minutes without air; 3 hours without shelter; 3 days without water; 3 weeks without food.   The two dens then went on to experiment in constructing debris huts using only the natural materials they could find.  They discovered that smaller shelters were warmer and quicker to build. They decided that this is an important survival technique in case one is lost or caught in bad weather. No outdoor training session would be complete without proper campfire building and safety lessons, which culminated in feasting on hot dogs cooked on a stick.    Somehow it just seems they taste so much better this way.     By the end of the session, everyone concluded that thanks to the volunteers at the Discovery Center, they were better prepared for the great outdoors.

Today is the “Longest” day of the year - the Summer Solstice. Called a variation of Midsummer by most northern cultures, this marks a day of great celebration. When man determined time by the sun and moon, midsummer was the middle of the growing season. Most celebrations took on a joyous quality. At Midsummer food was easier to find, herbs could be gathered and crops had been planted in anticipation of a bountiful harvest. It was considered by some cultures a good time to wed as it fell between the intense work of planting and harvesting of crops. The “downtime” could be spent in preparation and celebrations. In China it was a time of balance. Midsummer celebrated the earth, the feminine, and the yin forces. It complemented the winter solstice which celebrated the heavens, masculinity and yang forces.

Now with modern technology driving our lives, it is barely noticed. However, the natural world will be resetting its internal clocks to reflect the eventual slide toward the cold season. Now is the time for second clutches of eggs or litters and for the young to start their intense survival training. Sunlight drives the natural rhythm of plants. The work of photosynthesis has reached its peak and now food production will decline. With the gradual decrease in sunlight some plants will start setting buds for the next growing season. We owe this all to the 23.5º tilt of Mother Earth. It causes sunlight to be unevenly distributed over our planet’s surface as it orbits around the sun. This creates the seasons – the main driver behind the Rhythm of Life. (Originally posted 6-20-12)