An annotated copy of Porter's script for 'The Night Sky in January' on Venus (now the morning star), Saturn visible at dawn, Jupiter (the most visible planet in the evening sky), Mars below the Square of Pegasus, Mercury becoming visible, and Jupiter near Castor and Pollux in Gemini; Orion and Sirius, Uranus near Jupiter, and the Moon full when near Jupiter; the variable brightness of Mars; errors in the prediction of the brightness of Uranus; the brightness of stars and correlation of size, temperature and distance; Ptolemy and classification by magnitude, modern measurements of magnitude, human perception of the brightness of stars and the use of photographic and electronic methods; and the difficulties of exact comparison of stars in the southern hemisphere.