The night sky in October 2017

posted 30 Sep 2017, 15:49 by Pete Collins
by Anne Holt

Sunrise    1st:  07.10             31st: 07.06
Sunset     1st:  18.45             31st: 16.38

Astronomical darkness
!st:  20.42 to 05.18       31st: 18.36 to 05.09

Full Moon:  Oct 5th at 19.40     New Moon:  Oct 19th at 21-12

British Summer Time ends Sunday 29th at 02.00

Highlights

This month we have lots of astronomical darkness,  one major and several (very) minor meteor showers, a few very faint comets and another near Earth asteroid - but don't panic,  despite what you my have seen on some not very scientific internet sites, it isn't Nibiru and it isn't going to destroy the Earth. There are also some bright early evening passes of the ISS during the first half of the month. See Heavens Above for times.
Constellations

The Summer Triangle, made up of Vega in Lyra, Deneb in Cygnus and Altair in Aquila, is losing its dominance in the night sky.  It is still visible during the first part of October high in the south west but by the end of the month all three constellations will have set by 4am. It's place in the southern sky is being taken by the Great Square of Pegasus, autumn's signature constellation.

The beautiful star cluster the Pleiades (also known as the Seven Sisters) followed by the rest of Taurus, will be visible by 11pm in early October and by 8pm (now back to GMT) at month end.

By the end of October Orion will be easily visible by midnight, with Sirius just above the eastern horizon at this time.

Perseus and Andromeda are still high in the sky for most of the night, making it a good time to look for M31, the Andromeda galaxy.   If you are at a very dark sky site, it should be visible to the naked eye, especially when using averted vision.

Cassiopeia is now high in the sky for most of the night, so the Plough, on the opposite side of the North Celestial Pole, is low in the north.

Planets

Again, not the best time for planetary observation, the position of Mars does improve during the month but Venus and Saturn are both becoming less prominent.  However, it's better news for telescopic observations, the distant ice giants are both quite well placed.

Mercury:  in Virgo, mag -1.4. Hardly visible at all this month.  On 1st it rises only 44 minutes before the Sun and sets at sunset.  Brightens slightly over the next few days but rises closer and closer to sunrise.  Reaches superior conjunction on 8th but is not visible in the evening twilight for the remainder of the month.  Moves into Libra on 23rd.  By month end it will have faded to mag -0.4 and sets at 16.53 - only 15 minutes after the Sun.

Venus:  in Leo,  mag -3.9. Still very bright in the dawn sky but is visible for a minute or two less each day.  On 1st it rises at 04.41, almost two and a half hours before the Sun,  on 5th and 6th it is very close to the much fainter Mars - 22 arcminutes at its closest. It is now moving away from us so the disc appears quite small when seen through a telescope.  It moves into Virgo on 10th and by month end is rising less than 2 hours before the Sun.

Mars:  in Leo, mag 1.8. Not easy to see at the start of October.  On 1st it rises at 04.58,  just over 2 hours before the Sun, but is too faint to be seen in the dawn glow as it is now on the far side of its orbit, relative to Earth.  It moves into Virgo on 13th and on 17th is about 3 degrees below the 6% lit Moon.  By the end of October it rises more than 3 hours before the Sun and should be visible for a short while before the sky begins to brighten.

Jupiter:  not visible this month.

Saturn:in Ophiuchus, mag 0.5. On 1st it sets at 21.43 and should be visible very low in the SSW as the sky darkens.  It isn't easily seen after the first week of October,  on 24th it is 3.5 degrees SW of the 21% lit Moon but both are very low in the sky.  By month end it sets aboutt 2 hours after the Sun but isn't bright enough to be seen in the twilight.

Uranus:  in Pisces, mag 5.7. Still very well placed, it reaches opposition on 19th and is visible for most of the night throughout October.  On 1st it rises half an hour after sunset and reaches its highest point, about 45 degrees, at 02.10. On 31st it rises just before sunset and culminates (i.e. at its highest in the sky, due south) soon after 23.00.   Still bright - for Uranus - possibly visible to the naked eye from a very dark sky site, and a reasonable binocular target.  An amateur telescope should show a small greenish blue disc.

Neptune:  in Aquarius,  mag 7.8. The other distant ice world is also reasonably placed in October. On 1st it rises 45 minutes before Sunset and culminates at 23.00, about 29 degrees above the S horizon.  By month end it culminates at 20.20 and sets at 01.43, so can be seen during the earlier part of the evening.  It is much too faint to be seen with the naked eye or maybe even binoculars, but its blue colour should show in a reasonable sized scope.

For more details on planetary positions see

Meteor Showers

This month we have one major and a few minor showers - some so minor that they may well be non existent.

Orionids:  active late Sept to mid (or maybe late, depending on which source you believe) October.  Max Oct 21st/22nd  ZHR 20.  Enhanced activity probable for a few days either side of the peak.   These are fast moving meteors often leaving trails,  possibly including some fireballs.   This shower is caused when the Earth passes through dust clouds left by Comet 1P/Halley.  This year the Moon will be just past new on the date of maximum activity so will not interfere.

Minor Showers

Camelopardids:  peak 5th/6th   ZHR 1.   Not much activity in the last few years.

Draconids (AKA Giacobinids)  max 8th/9th  ZHR 2.  Usually includes many more meteors which are so faint that they can only be detected using radio or radar.   This shower occasionally shows more activity but is not predicted for this year.  2018 may be better.   parent comet 21P/ Giacobini-Zinner.

Delta Aurigids:  active mid Sept to mid October,  peak 11th ZHR 2.   Best seen in the early hours.

Southern Taurids:  active late September to Nov 19th,  peak 10th,  ZHR 5.  There are also several minor peaks in October and November.  These are bright, slow moving meteors often with coloured fireballs.  This shower is best seen around midnight. It is thought that the Southern and Northern Taurids were originally just one shower which was split into 2 by a close encounter with Jupiter many thousands of years ago.  The parent comet is long defunct - it broke into pieces, one of which is now Comet Encke.

Epsilon Geminids:  active 19th - 27th,  peak 18th/19th,  ZHR 2  fast moving meteors, probably debris from Comet Nishikawa-Takamizawa-Tago.

Leonids Minorids:  peak 24th,  ZHR 2.  parent comet C/1739K1.


Comets 

We have a few faint fuzzies this month.

2016B2 PanSTARRS passes through Orion's Belt.  It starts the month to the South of Alnilam, then between 10th and 14th passes only 10 arcminutes East of the star,  It then moves NE finishing October about half a degree North of Mintaka.  Magnitude at brightest expected to be around 10.

2017/01(ASSASN) passes through Perseus and Camelopardis, heading towards Polaris.  It s thought that this one could possibly brighten to mag 8, or even 7.

24P/Schaumasse travels Southwards through Leo's sickle asterism during October.   Starts the month at mag.12.1, expected to brighten to 10.7 by month end.

Moving in a parallel path to this, about 3 degrees South and a few days behind is the fainter 62P/Tsuchinshan, mag 13 brightening slightly to 12.4 by late October.

For exact positions of these at any time see www.cometwatch.co.uk or either of the websites given for planetary positions.

And finally ...

On Oct 12th, we have another close encounter with an asteroid.  At 10 - 30 metres long 2012 TC4 is smaller than last month's Florence, but will get much closer to us.  At 07.00 BST it will pass Earth at a distance of around 50,000 km.  Because it is so close, it will appear to move quite quickly against the background stars,  about half a degree per minute through Capricornus.  It will be very faint- mag 13 or 14 at maximum.
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