October Observing Guide

Hello all,

October's guide is below:

OBSERVING GUIDE
(Please note all times are BST unless otherwise stated and are based on an observing location of Belfast and covers the month of October)

The Sun

At the start of the month the Sun rises at 07:30 and sets at 19:00. By the end of the month, it rises at 07:25 UT and sets at 16:50 UT.

The Planets

Mercury is at inferior conjunction on the 6th, but is well placed for observation from mid-month onwards. It is at greatest western elongation on the 22nd. It is a morning object during the month. At mid-month it rises at 06:20 and is mag +0.6. By the 22nd, it rises at 06:15, almost two hours before the sun and is mag -0.5. By month’s end, it rises at 05:50 UT, an hour and an half before the sun and is mag -0.9. It can be located in Virgo.

Venus is an evening object this month and is currently moving slowly away from the Sun; however it is not well placed for observation as it appears very low in the sky at sunset. It sets less than an hour after the Sun at the start of the month at 19:45 and by month’s end; it sets over an hour after the Sun at 18:05 UT. It brightens from mag -3.9 to mag -4.0 during the month.

Mars is not visible this month.

Jupiter can be found in Sagittarius. It is currently low down in the sky and as a result poorly placed for observation. At the start of the month, it rises during daylight hours and sets at 23:15. By month’s end, it sets at 20:35 UT. It fades from mag -2.3 to mag -2.1 during the month. The four Galilean moons – Io, Europa, Ganymede and Callisto are visible with 10x50 binoculars or a small telescope and are worth a look.

Saturn is a morning object this month and can be located in Leo. It rises at 05:05 at the start of the month and by month’s end; it rises at 02:30 UT. It maintains its brightness at mag +1.0 during the month.

Uranus can be found in Aquarius and is well placed for observation. At the start of the month, it rises during daylight hours and sets at 05:45. By month’s end it sets at 02:40 UT. It is just within naked eye visibility and fades from mag +5.7 to mag +5.8 during the month. It can be located within four degrees to the North-East of Phi Aquarii.

Neptune can be found in Capricornus. At the start of the month, it rises during daylight hours and sets at 03:00 and by month’s end it sets at 23:55 UT. The planet lies to the North and slightly to the West of the pair of stars Delta and Gamma Capricorni. It maintains its brightness at mag +7.9 during the month.

The Moon

The first quarter moon is on the 7th with the full moon on the 14th. The last quarter moon is on the 21st with the new moon on the 28th.

On the evening of the 2nd, look out for the 11% illuminated waxing crescent moon, lying South-East of Venus, very low in the South-West.

On the evening of the 6th, the first quarter moon lies to the West of Jupiter.

On the evenings of the 9th and 10th, the waxing gibbous moon lies close to Neptune. On the 9th, a 73% illuminated moon lies to the West of the planet and the following night, a 82% illuminated moon lies to the East of the planet.

On the evenings of the 11th and 12th, the waxing gibbous moon lies close to Uranus. On the 11th, a 89% illuminated moon lies to the West of the planet and the following night, a 95% illuminated moon lies to the East of the planet.

On the morning of the 17th, a 92% illuminated waning gibbous moon lies to the East of M45 – The Pleiades.

On the morning of the 22nd, a 44% illuminated waning crescent moon lies to the South-East of M44 – The Beehive Cluster.

On the morning of the 25th, a 13% illuminated waning crescent moon lies to the South of Saturn.

On the morning of the 27th, a 2% illuminated waning crescent moon lies to the South of Mercury.

Meteors

The ZHR or Zenithal Hourly Rate is the number of meteors an observer would see in one hour under a clear, dark sky with a limiting apparent magnitude of 6.5 and if the radiant of the shower were in the zenith. The rate that can effectively be seen is nearly always lower and decreases as the radiant is closer to the horizon. The Zenith is the overhead point in the sky for an observer. The radiant is the point in the sky, from which (to a planetary observer) meteors appear to originate, i.e. the Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus.

There is one major shower and four minor showers this month. The first minor one is the Delta Aurigids. It peaks on the 3rd with a ZHR of 3. Lunar conditions for this peak are excellent with the 19% illuminated waxing crescent moon setting at 19:40 on the evening of the 3rd. The second shower of the month is the Draconids. They peak on the 8th with a variable ZHR. They are characteristly slow moving and lunar conditions for this peak are favourable with a 65% illuminated waxing gibbous moon in Capricornus setting at 00:30 on the morning of the 9th. Another minor shower this month is the Epsilon Geminids. They peak on the 18th with a ZHR of 2. Lunar conditions are poor for this peak with a 79% illuminated waning gibbous moon rising at 19:45 in Auriga on the evening of the 18th.

The major shower this month is the Orionids. They peak on the morning of the 21st at around 04:00 with a ZHR of 25. Lunar conditions are poor for this peak with a 56% illuminated waning gibbous moon rising at 22:20 on the evening of the 20th in Gemini. The shower is noted for fast meteors with persistent trains. The final shower of the month is the Leo Minorids. They peak on the 24th with a ZHR of 2. This peak is also affected by lunar interference with a 15% illuminated waning crescent moon rising at 04:00 on the morning of the 25th in Leo.

Asteroids

(4) Vesta is at opposition on the 31st when it will be mag +6.4. At the start of the month, it can be found in the head of Cetus, North of Menkar (Alpha Ceti). It then moves Westward as the month progresses and by month’s end has moved out of the head of Cetus, lying three degrees to the West of Gamma Ceti.

Comets

Comet 17/P Holmes is visible during October as a morning comet low in the East. It can be located in Cancer, lying roughly North-East of M44 – The Beehive Cluster. Its situation improves as the month goes on. Current predictions estimate its brightness around mag +7 with it expected to slowly fade.

Comet 29P/Schwassmann-Wachmann is also visible in Cancer during October. It lies roughly to the North of M44 – The Beehive Cluster. It was in outburst at the end of September which saw a three magnitude brightening down to mag +11.

Comet 2008/A1 McNaught can be located very low in the West after sunset. It starts October in Libra, moving into Ophiuchus by month’s end. It is predicted to start the month at mag +7 fading by one magnitude during October. Around the 21st, it will lie roughly to the North-West of globular cluster M107 and around the 25th; it will lie roughly to the North-West of Zeta Ophiuchii.

Comet 2006 OF2 Broughton starts October in Camelopardus and moves into Lynx by month’s end. It is circumpolar and thus well placed for observation. It is predicted to remain around mag +10 for the month.

Comet 2006 W3 Christensen starts October in Cassiopeia and moves into Cepheus by month’s end. It is also circumpolar and is predicted to remain around mag +10 for the month.

Comet 85P/Boethin is predicted to brighten from mag +12 to mag +9 during October. It can be located low in the South-West, moving Eastward away from Sagittarius towards Capricornus. It lies roughly North-East of Jupiter and South-West of Neptune.

Deep Sky

On the deep sky front this month, galaxies M81 and M82 can be observed in Ursa Major. Check out the constellation Canes Venatici with several galaxies including M51 - the Whirlpool Galaxy and M63 - the Sunflower Galaxy. In Lyra – M57 – The Ring Nebula can be observed. In Vulpecula – M27 – The Dumbbell Nebula can be found. In Andromeda, M31 – The Andromeda galaxy can be observed along with its satellite galaxies M32 and M110. In Perseus, there is the open cluster M34 and the excellent Double Cluster – NGC 869 and 884. In Triangulum, there is the galaxy M33. Finally Auriga is reappearing with its three open clusters M36, M37 and M38 as is Taurus with the excellent Pleiades – M45.

For further observing information, check out www.eaas.co.uk/stargazers.html

General Notes

Always keep an eye out for Aurorae. Check out www.stronge.org.uk/spaceweather.html for the most up-to-date information on the aurorae. On the morning of the 26th at 02:00, the clocks go back one hour and daylight saving ends.

Other interesting naked eye phenomena to look out for include the Zodiacal Light and the Gegenschein. Both are caused by sunlight reflecting off dust particles which are present in the solar system. The Zodiacal Light can be seen in the West after evening twilight has disappeared or in the East before the morning twilight. The best time of year to see the phenomenon is late-Feb to early-April in the evening sky and September/October in the morning sky -- it's then that the ecliptic, along which the cone of the zodiacal light lies, is steepest in our skies. The Gegenschein can be seen in the area of the sky opposite the sun. To view either, you must get yourself to a very dark site to cut out the light pollution. When trying to observe either of these phenomena, it is best to do so when the moon is below the horizon. If you are observing them when the moon has risen, restrict your efforts to the period 4 days either side of the new moon as otherwise the moonlight will be sufficient to drown them out.

Finally check out www.heavens-above.com for the latest passes of the International Space Station and satellites, details of Space Shuttle launches and passes and for details of Iridium Flare activity.

Clear Skies

Neill McKeown


Information Sources Used

www.skyviewcafe.com - Used for the Sun and Planets section. Also partly used for the Moon Section

Sky at Night Magazine Observing Guide and Interactive Planetarium

www.aerith.net and cometchasing.skyhound.com – Used for the Comet Section for information and finder charts

www.imo.net – Used in the Meteor section

BAA Handbook

Stardust Magazine

Sky Guide 2008 – South Dublin Astronomical Society

Excellent stuff as usual Neill.

It was great to finally meet you in person last week at Whirlpool.
Although I was worse for wear at that stage...
having been up 'observing' in the bar till 6:30 the night before and
of course after the meal I was running on adrenaline (and Becks!)

Thats great stuff Neill, thanks a million.