Tuesday, December 18, 2012

The DC Women's Hiking Group will hike Tues., Dec. 18th and Thurs., Dec. 20th at Aldrich Park in Ridgefield.
Take Farmingville Rd. to New Rd.
The park is off of New Rd.
Meet in parking area at 8:30am.

Tuesday, December 11, 2012

The DC Women's Hiking Group will hike Tues., Dec. 11th and Thurs., Dec. 13th at Bennetts Pond in Ridgefield.
Take Rt. 7 to Bennetts Farm Rd.
Follow Bennetts Farm Rd. to parking lot on right hand side of road.
Meet at 8:30am.

Saturday, December 8, 2012


December 2012 Constellation of the Month:  Triangulum

To the west of the great square of Pegasus, which we described last month, near the wishbone-shaped Perseus (January, 2012) 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 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.

Monday, December 3, 2012

The DC Women's Hiking Group will hike Tuesday, Dec. 4th and Thursday, Dec. 6th at Bear Mountain Reservation in Danbury, 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 in the parking area at 8:30am.