The Summer
Triangle Part 2 Altair
Altair is
the lowest of the three stars that make up the summer triangle. It is quite
easy to find as it has a fainter star either side of it. Aquila is the brightest
star in the constellation of Aquila the Eagle.
In mythology
the eagle was sent from Olympus to collect the shepherd by Ganymede, who was
destined to become the cup bearer of the gods.
Altair is
about 16 light years away meaning that light left the star in 1999. If you were
born in that year light that left Altair will be entering your eye this summer.
It is also the closest of the summer triangle stars. It is white in colour
which means that like Vega it is hotter than our Sun.
South of
Altair there is a line of three stars; the centre one eta which looks like a
letter ‘n’ is the most interesting. It is another of the so called variable
stars. It was discovered in York in 1784 by Edward Pigott who worked with John
Goodricke who discovered the variability of several stars including that of
beta Lyra. Both Beta Lyra and eta
Edward Pigott
Aquila were discovered on the same night September
12th 1784. Goodricke and Pigott are the fathers of variable star
astronomy.
Eta Aquila
can be seen to vary in brightness around every 7 days.
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