Papers of John Guy Porter

Two copies of Porter's script for 'The Night Sky in August' on Mercury in the morning sky; Jupiter and Saturn in the evening sky; Mars becoming the most interesting planet over the next few months, its path between the Pleiades and the Hyades, its path in coming months and its similarity in colour to Aldebaran, which it already exceeds in brightness; star clusters in Taurus, Auriga and Perseus, the advantages of the study of clusters, their common origin and distance, the Hyades cluster, and Aldebaran being unconnected with the Hyades, which have a common recession, seen as an eastward movement from the Earth; the use of this movement to determine the size and distance of this cluster, a method which cannot be applied to the Pleiades, which is a reflection nebula; the possible origin of the gas and dust causing this nebulosity, Pleione being a shell star, and the intermittent spectroscopic evidence for this; the stars making up the Pleiades, their great variation in size and temperature and their similarity to the Hyades, although the stars of the Hyades are much older; the majority of all stars being like the Sun, and not giants, although the giants such as Capella and Aldebaran are prominent; Capella being also a double star and unusual in that both stars are similar; and the supergiants of Auriga, Epsilon and Zeta Aurigae, both double stars, and the sizes of each component compared to the solar system.