October Skies

October Skies

No telescope necessary

Check out these amazing astronomical view this October.

Tonight is the full Moon and if we in the Northern Hemisphere it would be the first of 2 this month making their Halloween Moon a ‘blue’ Moon. This being the term for when there are 2 full Moons in a month as opposed to actually appearing blue!

The Moon will be fully illuminated as it appears on the opposite side of the earth to the Sun and this results in a full moon.

Along with tonight’s full Moon tonight is the best time to see Mercury as it is at its highest point above the horizon in the western sky after Sunset.

Mars will also rise an hour after the Moon making it easy to find in the Eastern Sky.

On the 13th, Mars will be at opposition – meaning it will be at its closest approach to Earth and its face will be fully illuminated by the Sun.

It will be brighter than any other time of the year and will be visible all night long.

Orionid Meteor Shower

The Orionid meteor shower marks the second occasion the Earth encounters the stream of debris left behind by Halley’s comet each year.

In October, Earth passes farther from the centre of Halley’s debris stream than in May, with the result the observed rates for the Orionids are lower than for the Eta Aquariids. Despite this, the Orionids remain a treat for meteor enthusiasts in the northern autumn and southern spring.

The Orionids peak on October 21/22 but that maximum is often quite broad with activity hovering close to the peak rates for as much as a week around the maximum.

There is a train of thought that suggests the peak rates vary over time, with a roughly 12 year periodicity, as a result of perturbations by the giant planet Jupiter Jupiter orbits the Sun once every 12 years.

Around 2008-2009the Orionids were markedly more active than expected, with maximum rates in the range 40-70. So if the theory is accurate it is now 12 years on from the peak of activity so it is possible the Orionids will again put on a better than expected show.

The radiant rises just before local midnight, meaning the meteors are best observed in the early hours of the morning. The radiant reaches its highest altitude in the hours before dawn. The Moon will not interfere this year, setting in the early evening, long before the radiant rises.

And as added bonus….

Observers watching the Orionids are in for an extra treat. While the Orionids are active, so too are the Northern and Southern Taurid meteor showers. Where the Orionids are fast meteors, Taurids are slow, and often bright and spectacular.

Although the rates of both the Northern and Southern Taurids are lower than those of the Orionids (typically just ~5 per hour), their activity makes observations of the Orionids even more fun and exciting.

As mentioned Mercury is the western evening sky after sunset and will be an easy target for the first half of October. Since it will be setting two hours later than the Sun for the first few days of the month. it will get harder to spot as the month goes along and it begins it moving back to the morning sky.

Venus this month is shining brightly in the eastern morning sky starting the month in Leo and moving to Virgo on the 23rd.

Mars reaches opposition this month and is at it brightest – rising early and visible all night this is a great chance to see the red planet.

Jupiter and Saturn are still in Sagittarius and only seven degrees apart at the beginning of October and right overhead at the start of the month. Because Jupiter travels faster around the Sun, by the end of the month the pair will be even closer to each other.

Donna the Astronomer

I am a keen astronomer lucky enough to live and work in Coonabarabran the Astronomy Capital of Australia! I am a ‘Drover’s Brat’ and discoverer of a couple of comets and asteroids. I operate Milroy Observatory and can show you how to best integrate dark sky experiences into your tourism, farm stay or AirBnB business.

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