Observing

Track Down Uranus (24th October 2017)

Having just passed opposition on the 19th October, the distant icy planet Uranus is nicely placed for observing in the evening sky during the coming weeks.  It is just a fraction too faint to be seen with the unaided eye, so you will need to use a pair of binoculars or a telescope.  Use the Stellarium charts below to assist you in tracking down this planet, discovered by William Herschel in 1781.

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Comet 2P Encke

Comet 2P is the shortest period comet with an orbital period of just 3.3 years.  Like Comet Halley, Comet Encke is named after the person who computed it’s orbit rather than it’s discoverer.

Currently (11th February), Comet 2P is around magnitude ten amongst the stars of Pisces in the south-western evening sky looping around the circlet of stars in Pisces.  It is however rapidly descending into the evening dusk and will lost from view by the first few days of March, by which time it should have reached around magnitude six.  Perihelion is reached in mid-March after which it is only visible to observers in the southern hemisphere.  A finder chart for pre-perihelion is below:

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Comet 45P Honda-Mrkos-Pajdusakova

Comet 45P reached it’s closest point to the Earth on 11th February (7.7 million miles away) away passed through perihelion on 31st December 2016.  It is classified as a short period comet, having been discovered in 1948 and has an orbital period of 2,015 days.

Predictions initially had Comet 45P reaching around magnitude 6.5 at around the time of closest approach to the Earth, however it has fallen short of this with brightness estimates placing it around magnitude 8 instead.  It is however in the range of binoculars and small telescopes and is therefore still worth tracking down.

Bright moonlight is currently (11th February) is hampering observing, however as the Moon starts to wane then observing prospects will improve.  Comet 45P is visible in the southern part of Hercules on 11th February, but quickly races along, passing through Corona Borealis, Bootes, Coma Berenices and then onto in Leo by the end of February, fading as it does so.  The chart below shows the comet’s position up until the end of February:

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Mars & Neptune Get Close – 31st December 2016:

Over the evenings of 31st December 2016 to 2nd January 2017, Mars & Neptune close up on each other in the western evening sky.  The below Stellarium generated graphics show the view on the evenings of 31st December 2016 and 2nd January 2017.

Neptune will require a reasonably sized pair of binoculars or small telescope to spot.  Alternatively a timed exposure photograph of say 20 to 30 seconds exposure from a tripod mounted camera should just about be able to pick up the dim eighth magnitude light from Neptune.

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The Moon, Jupiter & Spica Line Up -22nd December 2016:

On the morning of Thursday 22nd December, the crescent Moon, Jupiter and Spica in Virgo will line up in the pre-dawn sky.  Below image is generated from Stellarium:

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December’s Meteor Showers – The Geminids and the Ursids

Looking at meteor showers remains a popular past-time for the amateur astronomer and indeed more casual sky watchers as well.  No specialist equipment is needed, just your own eyes, warm clothing, a reclining chair, plus a clear sky of course!  During December, we have the chance to observe the year’s most active meteor shower plus an often overlooked one as well.

After the Perseids in August, the Geminids are probably the second most observed meteor shower of the year.  Active between December 6th and 17th, they reach maximum this year during the late evening of December 13th.  Unusually for meteor streams (which are usually associated with debris left over from comets) , the Geminids are linked with debris from asteroid 3200 Phaethon.  At maximum, the Geminids produce a Zenithal Hourly Rate*  of around 100 and with the radiant above the horizon from early evening through to dawn they can be observed right through the night if you are so inclined!

This year however, the Geminids have a bright Full Moon to contend with which unfortunately will ‘wash out’ all but the brightest meteors.  To counter this and to give yourself the best possible chance of observing as many meteors as you can it is advisable to observe with your back to the Moon or if you can use a local building or fence to hide the Moon while you look skywards.

The final meteor shower of 2016 are the Ursids.  The radiant lies near the star Kochab in Ursa Minor and is active from December 17th to the 25th, reaching maximum on the night of December 23rd/24th.  This radiant is circumpolar so is available all night, however best observing conditions will be before moonrise at around mid-night.  The Ursids are associated with Comet 8P/Tuttle and typically produce a Zenithal Hourly Rate of ten meteors at maximum.

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A meteor captured by NVAS Member Steve Williams

With meteor observing there is no particular ‘best direction’ to look, meteors can appear anywhere in the sky, however if you trace the path of each meteor you see back, then they will appear to come from one particular area called the radiant.  The Geminids are so called because they come from the constellation of Gemini, whilst the Ursids come from Ursa Minor.

Observing meteors can require a little patience.  There can be quite a few minutes between meteors whilst at other times you can observe two or three in very quick succession.  To give yourself the best possible chance of spotting meteors, give yourself 10 – 15 minutes to allow your eyes to get accustomed to the darkness and avoid bright lights.

 

*Zenithal Hourly Rate is the number of meteors you could expect to observe if the meteor radiant is at the zenith under a moonless sky with no light pollution, in reality this is unlikely to occur!  It is a measure of the meteor shower’s activity.