September 2017 Dark skies
The attached sky chart shows the stars for around 9pm BST in the middle of September.
To the WSW, low in the evening twilight glow, Jupiter is still visible for upto an hour or so after Sunset. This month is realistically the final chance to see the “King of the Planets” in the current observing season as by the middle of October, the Sun will be too close to the planet to observe it for the next couple of months. Around the 5th and 6th of September, the planet is just some 3-4 degrees above Spica, the brightest star in Virgo and on the evening of the 22nd, the grouping is joined by a very thin crescent Moon for those that enjoy a photo challenge.
Saturn still continues to display in the low SW skies, the gorgeous ring system giving the everlasting “wow” factor to observing the planet. Much like Jupiter, the planet has a large retinue of satellites - currently around 62 – and the largest and brightest of these, Titan, can be seen with 7x50 or 10x50 tripod mounted binoculars. Have a look at Saturn between the following dates when Titan passes close to Saturn during it’s 16 day long orbit of the planet and see if you can spot the “starlike” point of light that will be Titan. Best chances to catch Titan are, 3rd - 5th, 11th - 13th, 19th - 21st and 27th - 29th September. Good hunting! A crescent Moon will sit a couple of degrees above Saturn during the evening of the 26th.
Turning to the morning skies now, and things get rather interesting. We’ve a little “planetary dance” going on in which Mercury, Venus and Mars are all involved in.
Venus has been blazing away in the Eastern dawn sky for some time now but it is slowly starting to draw back in towards the Sun over the next couple of months. During September, those early risers amongst us will see Venus close in towards the two other planets on show in the morning sky, Mercury and Mars with the Moon joining this alignment from the 17th to 19th. Venus will become more involved in this morning alignment next month, so for September, we’ll focus on the Mercury – Mars encounter.
Visible in the dawn sky from the start of the month, Mercury will slowly brighten as it closes in to a close approach with Regulus, the brightest star in the constellation of Leo, around the 10th. The planet then drops away towards the Eastern horizon over the rest of the month, having a close encounter with Mars – which is doing a similar trick although moving somewhat slower – over the mornings of the 16th and 17th Sept. Mercury rapidly departs the scene and then the planet Venus starts to close in on Mars for the month end. Just to make things even more interesting, a thin crescent Moon will be passing through the same area of sky over the very same period. Cameras at the ready people!!!!
September unfortunately offers no major meteor showers to look out for, although there will always be non shower or sporadic meteors to be seen.
So, good luck and clear skies to you all,
Les Fry - Mid Wales Astronomy.