Friday, December 12, 2014

December 2014 Constellation of the Month: Triangulum





To the west of the great square of Pegasus, which we described last month, near the wishbone-shaped Perseus  is Triangulum.  It is a compact triangle with somewhat faint stars, so it will be a little challenging to find.  Some consider it an especially attractive constellation.
The big item of interest in Triangulum is the Triangulum Galaxy, M33.  It is the 3rd largest galaxy in our little Local Group of galaxies – after the Andromeda Galaxy (see Nov. 2012), and our own Milky Way.  When seen through binoculars or a small telescope, like the Discovery Center's, it is about the size of the full moon. 
Which brings us to the question we posed last month:  How many full moons, side-by-side, would it take to stretch across the sky in a line (arc) from the eastern horizon to the western horizon?  The answer is about 360 – which is a lot more than most people guess.  That, coincidentally, is the number of degrees in a circle.  Since the arc we're talking about is a half-circle, the Moon is about ½ degrees in diameter, as it appears to us in the sky.  This, in an extremely unlikely coincidence, is the same size as the disk of the Sun.  That is why, in a full eclipse of the sun, the Moon will almost exactly cover the disk Sun. 

You can prove this half-degree figure for yourself – and maybe win a bet or two, at sunset (or moonset).  When the bottom of the circle of the sun touches the horizon in the West, how long will it take for the Sun to completely set?  The answer is 2 minutes, which is a lot quicker than most people would guess.

Here's how you can use that information to calculate with width of the Sun or Moon in degrees of a circle.  The Sun or Moon traverse across the half-circle (180 degrees) of the sky in 12 hours, which is 720 minutes.  2 minutes is 1/360th of 720 minutes.  1/360th of 180 degrees (the arc of the sky) is ½ degree.


Friday, December 5, 2014

The DC Women's Hiking Group will meet Tues., Dec. 9th and Thurs., 11th at Michael Ciaiola Conservation Area in Patterson, NY.

Take I-84 West to exit 20 for I-684 toward NY-22/White Plains/Pawling.
Keep right at the fork, follow signs for NY 22/Brewster/Pawling and merge onto I-684N.
Continue on NY-22N.
Turn right onto Haviland Hollow Rd.
The Conservation Area will be on the left.
Meet at 8:30am.

Sunday, November 23, 2014

The DC Women's Hiking Group will hike at Quarry Head in Wilton, CT on Tues., Nov. 25th.  No hike Thursday, Nov. 27th.  Happy Thanksgiving!

 Take Rt. 35 past the fountain and follow onto Rt. 33 into Wilton.
There will be a State of CT brown sign on the left hand side between mailboxes #760 and #764.
Turn left into the road and follow up the hill.
There will be a sign for parking up ahead.
Meet at 8:30am.

Sunday, November 16, 2014

The DC Womens Hiking Group will meet at Lewisboro Park in NY this week, Tues., Nov. 18th and Thurs., Nov. 20th.
Located on the south side of Rt. 35 between Mead Street and Bouton Road in South Salem.
Turn at white sign for Lewisboro Park off of Rt. 35 and follow up hill to upper parking area.
Meet at 8:30am.

Monday, November 3, 2014

The DC Women's Hiking Group will hike Thurs., Nov. 13th at Florida Refuge in Ridgefield, CT.
No school on Tues., Nov. 11th, so no hike planned.
Take Rt. 7 and turn onto Florida Hill Road. Make a right onto High Valley Road.
Park along the side of High Valley Road closest to Florida Hill Road.
Meet at 8:30am.
The DC  Women's Hiking Group will hike Thursday, Nov. 6th at Weir Farm.
No school on Tuesday, Nov. 4th, so no hike planned.

 Take Branchville Road and follow National Park signs to Weir Farm.

 Meet in parking lot on Nod Hill Rd. across from historic buildings at 8:30am.

Friday, October 31, 2014

November 2014 Constellations of the Month: Pegasus and Andromeda



High in the sky and a little to the West are our November 2014 constellations of the month, Pegasus and Andromeda.  They are east of July's constellation of the month, the Summer Triangle.

They look like a big square, with some appendages.  This is called the Great Square of Pegasus, even though the northeast star in the square belongs to Andromeda (which is why we needed to have 2 constellations this month).  Can you guess how many side-by-side Full Moons it would take to stretch across one side of the square? 

At the end of one of the appendages is the globular star cluster M15, which has about 100,000 stars.  Globular clusters, unlike other stars and clusters we see in our Milky Way galaxy, are not located in the disk of the galaxy.  They are found "above" and "below" (there is no direction which is "up" or "down" in space) the central part of the disk.  They formed before the rest of the galaxy took shape. 

Andromeda's stars are relatively faint, and they don't form a recognizable shape.  But the constellation has one major attraction – M 31, the Andromeda Galaxy.   It is a huge spiral galaxy which looks much like our own Milky Way.  It is bigger than the Milky Way and contains about a trillion stars, which is at least twice as many as the Milky Way.  It is bright enough to be seen with the naked eye.   It appears so bright, because it is so close -- only 2.5 million light years (16 trillion miles) away.  With the naked eye, it looks about as wide as 3 Full Moons.

... which brings us to the earlier question of how many Full Moons would stretch across a side of the Great Square – Answer: about 30.  That's a lot more than most of us would guess.  The Moon appears to us as about half a degree wide, and a semicircle across the sky from one horizon to the opposite horizon is 180 degrees.  So, about 360 Full Moons side-by-side would be required to traverse the sky from horizon to  horizon.


Monday, October 27, 2014

The DC Women's Hiking Group will hike this week, Tuesday, Oct. 28th and Thursday, Oct. 30th at Tarrywille Park in Danbury.

From I-84 take the airport exit.
At end of ramp turn right.
Follow through traffic lights and at stop sign turn onto Southern Blvd. ( It will be a sharp right turn).
Follow small brown signs for Tarrywile Park.
The park will be on the right, across from Immaculate H.S.
Meet in lower parking lot at 8:30am.

Monday, October 20, 2014

The DC Women's Hiking Group will hike Tues., Oct. 21st and Thurs., Oct. 23rd at Scott Lot Preserve in Redding, CT.
Coming from the north on Route 7 turn left onto Old Redding Rd. Right after going under RR bear right onto Mountain Rd. Follow Mountain Rd. to end and turn left onto Peaceable St. Parking for the open space will be on the left. If you come to an electrical substation, you went too far.
Meet at 8:30am.

Sunday, October 12, 2014

The DC Women's Hiking Group will hike Tues., Oct. 14th at Seth Low Pierrepont State Park.
Entrance and parking is off Barlow Mountain Rd. across from Scotland and Barlow Mountain Elementary Schools.
Meet at 8:30am in parking area.

Sunday, October 5, 2014

The DC Women's Hiking Group will hike Tues., Oct. 7th and Thurs., Oct. 9th at Bear Mountain Reservation in CT.
Take exit 5 off of I-84. Follow Rt. 37 North past all the shopping centers. Go past the
commercialized district and eventually past the federal prison into the more
rural part of northern Danbury. About 0.2 mile past the prison entrance, on
the right, is Bear Mountain Road which is 2.8 miles from I-84. Turn right
onto Bear Mountain Road and follow it for 0.5 mile. Turn right into the
entrance of Bear Mountain Reservation.
Meet at 8:30am.

Monday, September 29, 2014

The DC Women's Hiking Group will meet at Bennetts Pond this week on Tues., Sept. 30th and Thurs., Oct. 2nd.
From Rt. 7 head North towards Danbury.
Bennetts Farm Rd. will be on the left.
Follow Bennetts Farm Rd. to parking area on right and signage for the Park.
Meet at 8:30am.

Monday, September 22, 2014

The DC Women's Hiking Group will hike this week, Tuesday, Sept. 23rd and Thursday, Sept. 25th at Tarrywille Park in Danbury.

From I-84 take the airport exit.
At end of ramp turn right.
Follow through traffic lights and at stop sign turn onto Southern Blvd. ( It will be a sharp right turn).
Follow small brown signs for Tarrywile Park.
The park will be on the right, across from Immaculate H.S.
Meet in lower parking lot at 8:30am.

Monday, September 15, 2014

The DC Women's Hiking Group will meet at Topstone Park in Redding on Tues., Sept., 16th and Thurs., Sept. 18th.

Take Topstone Rd. off of Rt. 7.
Follow road over RR tracks until it becomes a dirt road.
Shortly after, a parking area will be on the right side of the road.
Meet at 8:30am.

Monday, September 8, 2014

The DC Women's Hiking Group will meet Tues., Sept. 9th and Thurs., Sept. 11th at Lake Windwing.
Now that the children are back at school, come join us for a hike!
Take Rt. 35 to the traffic light at Limestone Rd.
Turn left on to Limestone Rd.
Follow Limestone, it will turn into Bennetts Farm Rd.
Follow to across from Ridgebury Elementary School and turn right on to South Shore Dr.
Turn left into baseball field and parking area.
Meet at 8:30am.

Thursday, September 4, 2014

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.