BAS Observer November 2017

16 BAS OBSERVER The sky in November by Peter Allison T he nights are getting shorter, and observing now starts later in the evening. This is just one of the summer-month challenges for amateur astronomers, but there are still plenty of astronomical reasons this month to get your telescope out under a dark sky. Dark-sky nights From about Wednesday, 8th November, the Moon starts setting late enough to give some reasonably dark observing hours before it rises late in the evening. After New Moon you will have to wait until the Moon sets to have a properly dark sky. So . . . 8th–1 9 th November looks best this month. BEST DARK-SKY OBSERVING DATES FOR NOVEMBER Day Date Moonrise Dark sky from sundown until moonrise Wednesday 8th Moon rises at 10.26 p.m. Thursday 9 th Moon rises at 11.22 p.m. Friday 10th Moon rises after midnight. Saturday 1 1 th Moon rises at 12.13 a.m. Sunday 1 2 th Moon rises at 1.3 9 a.m. Monday 13th Moon rises at 2.17 a.m. Tuesday 1 4 th Moon rises at 2.53 a.m. Wednesday 15th Moon rises at 3.29 a.m. Thursday 1 6 th Moon rises at 4.04 a.m. Friday 17th Moon rises at 4.41 a.m. Moon interference until evening moonset Saturday 18th New Moon Sunday 1 9 th Moon sets 33 minutes after sunset. Alignment stars Two prominent and widely spaced stars that are good for telescope alignment are Rigel in the constellation Orion (the Hunter) and Achernar in Eridanus (the River). Rigel is the easier to find, as it is very bright and is located at the foot of distinctive Orion. Eridanus is a bit harder to recognise; however, the constellation starts at Rigel and wanders westward in a snaking path to terminate at Achernar. Achernar is reasonably bright in a fairly sparse region of sky. Orion Eridanus Alignment stars: • Achernar • Rigel