M31 - The Great Galaxy in Andromeda
M31 is the "most
distant naked-eye object visible to the naked eye". It is pretty
difficult to see with the naked eye except under extremely dark and
clear skies. It is easily found with binoculars, however.
This is a telescopic photograph made with the new CCD camera and an
8-inch telescope. Students Chloe Stuber and Jake Lyerly helped
operate the telescope and camera on Wednesday, Oct. 10,
2007. The galaxy is so huge that it takes many frames to piece
together to capture the whole galaxy which is about 3 times the angular
size of the Moon. We made 11 overlapping frames that will
eventually be stitched together into one large image. The result
here is only two frames. Students will soon help assemble the
The galaxy is extremely distant, but it is the closest spiral galaxy to
our own Milky Way galaxy and is believed to be very similar in
structure and size as our own Milky Way galaxy. The distance is
over 2 Million light years, and the galaxy is about 100,000 light years
across. The stars number about 100 billion (1011).
The individual stars cannot be seen except in very large
telescopes. All the stars in the photograph are foreground stars
in our own Milky Way galaxy.
Notice that dust lanes can be clearly seen in the photograph.
These are areas of material that will form new stars during some
epoch. Similar dust dominates the Milky Way.
M31 is featured on another Physics Photo of the Week on November
17, 2006. Watch for more images of this when students finish
assembling the complete image.
Photo of the
published weekly during the academic year on Fridays by the Warren
Wilson College Physics
Department. These photos feature an interesting phenomena in
the world around us. Students, faculty, and others are invited to
submit digital (or film) photographs for publication and
explanation. Atmospheric phenomena are especially welcome.
Please send any photos to firstname.lastname@example.org.