The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy 21 million light-years (6.4 megaparsecs)away from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.
On February 28, 2006, NASA and the European Space Agency released a very detailed image of the Pinwheel Galaxy, which was the largest and most-detailed image of a galaxy by Hubble Space Telescope at the time. The image was composed of 51 individual exposures, plus some extra ground-based photos.
On August 24, 2011, a Type Ia supernova, SN 2011fe, was discovered in M101.
Pierre Méchain, the discoverer of Messier 101, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear. It is difficult to distinguish when one lits the wires."
William Herschel noted in 1784 that "...in my 7-, 10-, and 20-feet reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed."
Lord Rosse observed M101 in his 72-inch-diameter Newtonian reflector during the second half of the 19th century. He was the first to make extensive note of the spiral structure and made several sketches.
To observe the spiral structure in modern instruments requires a fairly large instrument, very dark skies, and a low-power eyepiece.
Statistics for this Xoptio
Most beautiful Galaxy 50
%
50
% Not particular beautiful
I like it 50
%
50
% Nothing to say
Would like to go some day 50
%
50
% Might not exist any more
See statistics
