The Summer Triangle
An Asterism
The Milky Way Through the
Summer Triangle
Credit and Copyright: Andy Steere
http://apod.nasa.gov/apod/image/9612/sumtri_as_big.jpg
Deneb Vega
Altair
(From left to right)
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Picture represents a 10 minute exposure
Behind the Summer Triangle lies some of the vast star
fields of our Milky Way Galaxy, containing literally
billions of stars.
The dark band across the middle that seems to divide
the stars is actually interstellar dust, which absorbs
more visible light than it emits and so appears dark.
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The first
magnitude stars
of the setting
Summer
Triangle are all
seen in context:
Vega of Lyra
Deneb of
Cygnus and
Altair of Aquila.
http://www.astro.uiuc.edu/~kaler/sow/sumtri-t.html
http://www.perkins-observatory.org/educational%20files/summer.pdf
Lyra,
the lyre
or small
harp
http://upload.wikimedia.org/wikipedia/commons/2/29/Lyra_constellation_map.png
Vega
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In Lyra
25 lt yr away
25x brighter than
our Sun
3rd brightest star in
Northern
Hemisphere
http://stardate.org/images/constellations/lyra.gif
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From Arabic an-nasar al-waqui
meaning ‘swooping vulture’ or
‘swooping eagle’
Inspired song ‘Twinkle, twinkle, little
star’
Will be the next pole star in 14,000 AD
Was pole star in 12,000 BC
First star to be photographed
Central star in Carl Sagan book/movie
Contact
Aquila, the Eagle
http://upload.wikimedia.org/wikipedia/en/7/7c/Aquila_constellation_map.png
Altair
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In Aquila, the Eagle
17 lt yr away
12x brighter than our Sun
8th brightest star in Northern
Hemisphere
At vertex of Summer Triangle
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From Arabic for flier
Was star for planet Altair IV in sci-fi
movie The Forbidden Planet
Cygnus, the Swan
Constellation
Cygnus also
called the
Northern
Cross- Deneb is
at the top
http://www.astronomytoday.com/astronomy/cygnus.html
Deneb
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3,200 lt yr away
in Cygnus, the swan
200,000x brighter than our Sun
14th brightest star in Northern
Hemisphere
‘Dheneb’ is Arabic word for tail
More on Deneb
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One of the biggest supergiants known
Would fill the space inside Earth’s orbit
If at same distance as Vega would
cast shadows at night and be visible
during the day!
A Japanese legend of
star-crossed lovers
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The star Vega represented Orihime, who produced
brilliantly colored fabrics.
Across the "Heavenly River" (the Milky Way), Altair
represented the cowherd Kengyu.
After meeting each other they received divine
permission to marry, whereupon both abandoned
their occupations. This angered the gods who
separated them and sent them back to their original
jobs on opposite sides of the heavenly river. The
couple however, received permission from the gods
to get together for one night each year.
http://www.space.com/spacewatch/070706_ns_summer_triangle.html
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That special night is July 7 – but only if the sky
is clear!
As a result, the evening of July 7 has evolved
into a young-people's holiday in Japan called
Tanabata.
Prayers are then offered for clear skies so that
Orihime and Kengyu, the star-crossed lovers can
be reunited.
One popular Tanabata custom is to write one's
wishes on a piece of paper, and hang that piece
of paper on a specially erected bamboo tree, in
the hope that the wishes come true.
For the Chinese…
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Vega and Altair are two lovers, a fairy
weaver and a cowherd, separated by a
great river (the Milky Way).
Once each year, a huge flock of
magpies form a bridge over Deneb to
allow the lovers to spend the night
together. This night is Qi Qiao Jie, the
Chinese equivalent of Valentine's Day.
http://www.bbc.co.uk/dna/h2g2/A3784773
http://www.astronomy.net/graphics/articles/24/summertriangle_sm.jpg
http://r-clarke.org.uk/summer_triangle.htm
References
LA Astronomy Society
http://www.laas.org/Bulletin/August_20
07.pdf
NewsOK.com
H2g2 (BBC News)
ClarkFoundation.org