Updating to 3 71 m33
The Triangulum galaxy (M33) will be well placed for observation.It will reach its highest point in the sky at around midnight local time.Knowing the sizes and temperatures of the stars they were able to measure the absolute magnitude of the stars.When the visual and absolute magnitudes are known, the distance to the star can be measured.In 1922–23, John Charles Duncan and Max Wolf discovered variable stars in the nebulae.Edwin Hubble showed in 1926 that 35 of these stars were classical Cepheids, thereby allowing him to estimate their distances.The Triangulum Galaxy is sometimes informally referred to as the "Pinwheel Galaxy" by some amateur astronomy references However, the SIMBAD Astronomical Database, a professional astronomy database that contains formal designations for astronomical objects, indicates that the name Pinwheel Galaxy is used to refer to Messier 101, Being a diffuse object, its visibility is strongly affected by small amounts of light pollution.It ranges from easily visible by direct vision in dark skies to a difficult averted vision object in rural or suburban skies.
It is one of the largest H II regions known, with a diameter of nearly 1500 light-years and a spectrum similar to that of the Orion Nebula.
The galaxy was independently discovered by Charles Messier on the night of August 25–26, 1764.
It was published in his Catalog of Nebulae and Star Clusters (1771) as object number 33; hence the name M33.
The Triangulum Galaxy was probably discovered by the Italian astronomer Giovanni Battista Hodierna before 1654.
In his work De systemate orbis cometici; deque admirandis coeli caracteribus ("About the systematics of the cometary orbit, and about the admirable objects of the sky"), he listed it as a cloud-like nebulosity or obscuration and gave the cryptic description, "near the Triangle hinc inde".