In this occasional series, Dr Niall Smith - a director of CIT Blackrock Castle Observatory in Cork - will guide you through all things astronomical. So get looking ...
THE stars of the winter/spring sky are now giving way to those of summer. You may notice there are fewer bright stars at this time of year.
This happens because in summer the night side of Earth is facing away from the centre of our galaxy (the Milky Way), rather than towards it, so there are literally fewer nearby stars to see.
One star which is visible in the night sky at any time of the year from Ireland is the North Star or Polaris. It is the only star in the entire sky to remain stationary. It is not especially bright and the easiest way to find it is via the two end stars in the constellation of the Plough.
See the accompanying skymatters newsletter for May at the bottom of this article. Just navigate to full screen version and print out.
Once you have identified Polaris you will always have the comfort of being able to find north — at least if the sky is clear!
On the night of May 6 and morning of May 7 you can catch a glimpse of the peak of the Eta Aquarids meteor shower — the best time is after midnight, which is admittedly late, but it is thankfully a Friday night.
These meteors (or shooting stars) are caused when tiny dust particles left over from the tail of Halley’s Comet burn up in the Earth’s atmosphere as the Earth itself ploughs through this vestige of the tail of the comet.
The best way to view meteors is with a warm jumper, the occasional cup of hot tea, and your own eyes — no binoculars or telescopes.
To give yourself the best chance of seeing some Eta Aquarids give your eyes up to 20 minutes to fully adapt to the dark and don’t be tempted to look at your mobile phone while you wait as this will destroy your night vision.
Look generally northwards, but expect meteors from any direction. Meteors last for a fraction of a second (rarely a little longer, if you are very lucky to catch a bright one) and they arrive unannounced, so be vigilant for the greatest chance of success.
This year the Moon is “new” on May 6 meaning it is below the horizon throughout the night making for potentially excellent dark skies.
On May 9, a relatively rare event takes place when Mercury moves across the face of the Sun in a so-called transit.
This event is very well timed for Ireland, starting around 11:12am and ending around 6:35pm, but it is tricky to observe. You will need either binoculars or a telescope, and they must either be fitted with a proper solar filter or use the projection method. (See May’s accompanying skymatters newslette below)
NEVER look at the sun with your own eyes, or with binoculars or a telescope not fitted with a solar filter, as instant blindness can occur.
The Earth and Mars are the closest they have been for 10 years on May 22. Mars will unfortunately be low in the south-east sky about 15 degrees to the east of the full moon and about 15 degrees above the horizon at 1:30 am on the 23rd. If you do stay up to look at Mars, cast a glance to the south-east where you will see Saturn just below and to the right of the full moon.
You can see an average of one satellite every two-three minutes. Satellites can be seen as points of light which take a couple of leisurely minutes to cross the night sky. They can be quite faint and they can brighten and dim as they tumble in space.
Dr Niall Smith is director of CIT Blackrock Castle Observatory in Cork. An astrophysicist, he is also head of research at CIT. If you have any astronomy questions for Niall, email firstname.lastname@example.org
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