The Night Sky in December

Abstract

New moon occurs on Dec. 12d. 12h. 53m., u.t., and full moon on Dec. 27d. 20h. 27m. The following conjunctions with the moon take place: Dec. 3d. 14h., Saturn 4° S.; Dec. 4d. 04h., Mars 3° S.; Dec. lid. llh., Mercury 2° N.; Dec. 14d. 20h., Venus 3° N.; Dec. 30d. 21h., Saturn 4° S.; Dec. 31d. 23h., Mars 2° S. In addition to these conjunctions with the moon, Mercury is in conjunction with Jupiter on Dec. 15d. 02h., Mercury being 0·6° S. Mercury is a morning star throughout most of the month, rising at 6h. 04m., and 7h. 12m. at the beginning and middle of the month respectively; on Dec. 31 the planet rises 12m. after the sun. Venus, an evening star, is conspicuous in the western sky for some time after sunset as an object of stellar magnitude – 3·4; about 0·9 of the illuminated1 portion of the apparent disk is visible during the month. Mars, in the constellation of Leo, can be seen throughout the greater portion of the night, rising at 22h. 23m., 21h. 52m., and 21h. 04m., at the beginning, middle and end of the month, respectively, and is easily recognized from its proximity to Regulus, from which it moves eastward during the month. Jupiter, in conjunction with the sun on Dec. 1, is unfavourably placed for observation until the end of the month, when it is a morning star rising about 1¾ hours before the sun. Saturn, in the constellation of Leo, is well placed for observation, rising at 21h. 46m., 20h. 50m., and 19h. 44m., at the beginning, middle and end of the month, respectively. Occultations of stars brighter than magnitude 6 are as follows: Dec. 2d. 04h. 53·2m., λ Cane. (R); Dec. 8d. 06h. 20·5m., m. Virg. (R); Dec. 25d. 23h. 40·2m., x Taur. (D); Dec. 26d. 00h. 09·7m., u Taur. (D). The times are given for Greenwich, and D and R refer to disappearance and reappearance, respectively. The Geminid meteors are active in the early part of the month; they have usually short paths and are not very bright. Winter solstice takes place on Dec. 22d. 17h.