September 2017 Sky Calendar
Dec 7, 2017 4:03:09 GMT
Post by Joe on Dec 7, 2017 4:03:09 GMT
CVAS Monthly Sky Calendar for September 2017
Jupiter – Jupiter is best viewed in the SW/W skies right after it gets dark enough to view it. As it approaches conjunction with the Sun next month on the 26th, it not up for long after sunset; to start the month it is up for less than 2 hours after sunset, at month’s end it is up for less than 1 hour. Even at the beginning of the month it is only 17° high at sunset and only gets lower as the month goes on, so getting a good look at it will be difficult since it will be low on the horizon. During to the month, its magnitude will go from -1.77 to -1.70 and its diameter going from 32.0 to 30.91 arc-seconds.
Saturn- Best viewed in the southern skies as soon as it gets dark enough to view it. During to the month, its magnitude will go from 0.45 to 0.54 and its diameter going from 16.9 to 16.1 arc-seconds. Saturn rings will be tilted 27° to us. The rings them self will be about 37 arc-seconds in size this month. To start the month it is up for close to 5 hours after sunset, at month’s end it is up for less than 4 hours after sunset.
Neptune – Neptune will be at opposition on the 5th this month, which means it will be at its closet point to the Earth for this year. When a planet is at opposition, it is like the full moon, it will be basically up all night. To start the month it is up for about 11 hours after sunset, at month’s end it is up nearer to 10 hours after sunset. Since the planet is rising near sunset, it is best to wait for a few hours until it is higher up when it is in the southern skies. This is a good time also to try to see Neptune largest moon, Triton, which will be around magnitude 14.1, probably at least a 10” or larger telescope will be needed. Neptune’s magnitude will around 7.82 with a diameter of around 2.31 arc-seconds during the month.
Uranus – To start the month it is best viewed later in the night when it higher up in the south, around 3 or 4AM. Later in the month, Uranus will be in the southern skies closer to 2AM. Uranus will be at opposition on October 19th this year. As it approaches opposition it too is basically up all night. To start the month it is up for 9 ½ hours after sunset, at month’s end it is up for 11 1/2 hours after sunset. Its magnitude will around 5.71 with a diameter of around 3.7 arc-seconds during the month.
See is.gd/urnep/ for finder charts for Uranus and Neptune from Sky&Telescope.
Venus – Venus also can be found in the eastern morning sky before sunrise. At the beginning of the month, it is up for little under 3 hours before sunrise, by month’s end it is up for just over 2 hours before sunrise, with it being 29° to 23° high at sunrise for the month. During the month it is at a gibbous phase, going from a 83% phase with a size of 12.4 arc-seconds to a phase of 91% with a size of 11.2 arc-seconds. Its magnitude is close to magnitude -3.95 for the whole month.
Mars – After being in conjunction with the Sun on July 27th, it now can be found low in the Eastern morning skies in Leo. But for the entire month, and actually for the next few months, it will not be much to look at. To start the month it is up for only about an hour before sunrise, by month’s end this will increase to near 2 hours. But with a size only around 3.6 arc-seconds for the month, it is pretty small; Uranus is actually bigger in appearance than Mars for most of this month. Mar’s magnitude will be around 1.8 for the month.
Mercury – For the entire month Mercury is located in the Eastern morning skies. After just being in inferior conjunction with the Sun on the August 26th, to start the month, it is up for about 40 minutes before sunrise. After the first week of month, it climbs higher and is up for around 1 ½ hours before sunrise for a week or so. Then it starts to sink down again and get closer to the Sun again as it approaches Superior Conjunction with the Sun on October 8th and is up for less than 40 minutes to end the month. So for a week, centered on the 11th/12th it is a good opportunity to try to see the planet. To start the month its phase will be at 6%, at a size of 10 arc-seconds, with a magnitude of 3.0. To end the month its phase will be at 97%, at a size of 5 arc-seconds, with a magnitude of -1.33.