Andromeda is a large constellation, more than 1400 times the size of the full moon. However, it is only 55% of the size of Hydra, the largest constellation. It is a northern sky constellation with one hour right ascension and 40° north declination. As its name implies, the Andromeda galaxy can also be found within this constellation. The Andromeda galaxy is the closest barred spiral galaxy to us and one of the brightest Messier objects. The constellation's brightest star is Alpheratz, the star closest to Pegasus.
To locate Andromeda, the author believes that the best way is to find first find Pegasus using the Great Square of Pegasus, and utilising that to locate Alpheratz. Alpheratz forms one of the four corners of the square.
This is a rough drawing of Andromeda, with its neighbouring constellations.
Alpheratz, also known as Alpha Andromedae, appears to the naked eye as a single star. However, it is a binary system with two stars in close orbit. The brighter of the two stars have a unusual chemical composition of mercury and manganese, and is 100 times brighter than the Sun. Interestingly, this chemical peculiarity has been attributed to the idea of "radiation pressure". In stars with calm atmospheres, heavier elements sink due to gravity, while others are pushed to the surface by "radiation pressure". Essentially, this is the pressure exerted upon a surface due to exchange of momentum between the object and an electromagnetic field. Sadly, this force is too small to be noticed under everyday circumstances.
Up next is Antlia.