December 2017 Sky Calendar
Dec 7, 2017 4:12:27 GMT
Post by Joe on Dec 7, 2017 4:12:27 GMT
CVAS Monthly Sky Calendar for December 2017
Mercury – To start the month it can be found the very low on the south-western horizon right at sunset. During the first week of the month, it is up for over an hour with being around 8° high after sunset. During this first week it will have crescent phase of less than 39%, a magnitude between 0.1 to 0.9., and a size of around 8/9 arc-seconds. But as Mercury approaches Inferior Conjunction on the 13th of this month, it will drop of the evening sky and then can be found in the morning sky the last half of the month. By month’s end it will be up for over 1½ hours and being 15 degrees high at sunrise, which is actually very good for Mercury. During the last 15 days of the month, it phase will go from 3% to 57%, it size from 9.8 to 7.0 arc-seconds, and it magnitude from 3.7 to -0.2.
Saturn- To start the month it might be able to seen very low on the horizon in the south-western skies right after sunset. But as it nears conjunction with the Sun on the 21st it will be not be able to be seen the rest of the month after the first week or so. To start the month it is up for around 1 hour being 11 degrees high right at sunset. The size of Saturn itself (not the rings) will be at 15 arc-seconds with a magnitude of 0.5 for the month.
Neptune – Neptune is best viewed in the evening skies as soon as it gets dark out. It will be in the southern skies, being around 40° high right after civil twilight ends for the whole month. During the month it’s size will be around 2.2 arc-seconds with a magnitude of 7.9.
Uranus – Uranus best viewed a couple hours after sunset when it is higher in the SE/S skies. It is still up for a good part of the night with it being up close to 11 hours to start the month, by months end it is up for only around 9 hours. During the month, its magnitude will around 5.7 with a diameter of 3.6 arc-seconds.
See is.gd/urnep/ for finder charts for Uranus and Neptune from Sky&Telescope.
Mars – Mars can be found low in the south-eastern morning skies during the month. While it is getting easier to see with it being a little over 30 degrees high and up 4 to 4 ½ hours before sunrise for the month, seeing any real details on it will be difficult until around spring next year. With a size of 4.2 to 4.8 arc-seconds for the month, it is still pretty small. Mar’s magnitude increases slightly during the month going from 1.7 to 1.5.
Jupiter – Jupiter can be lower in the south-eastern morning skies this month. To start the month it is up for around 2 hours and being 22° high by sunrise. By month’s end, it will be easier to see being 31° high at sunrise and up for over 4 hours. During the month the size goes from 31.3 to 32.9 arc-seconds with a magnitude will be from -1.7 to -1.8 for the month.
Venus – Venus can be found very low on the south-eastern horizon right before sunrise. As it approaches Superior Conjunction with the Sun on January 9th, it gets even lower as the month goes on and probably will not be visible the last part of the month. At the beginning of the month, it is up for a little under 1 hour before sunrise, with it being only 7 degrees high before the sun comes up.
Its phase for the month will be near 100% with a size near 10 arc-seconds and a magnitude round -3.9 for the whole month.
Gemind Meteor Shower – The Geminds are predicted to peak on the night of 13th. This should be a good year for this shower since the moon does not rise until around 4AM that night with it being only a small crescent. The Geminds typically out-perform the more publicized Perseid meteor shower with the Geminds having a zenithal hourly rate of 120. Also a nice thing about this shower is that some meteors are visible in the evening skies as opposed to all other major showers which are best viewed in the early morning hours right before sunrise. Geminds meteors usually move at medium to slow speeds and often produce fireballs.
Winter Solstice – The Winter Solstice, the office start of winter, arrives at 11:28AM on the 21st.