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The night sky of May

Dear friends of astronomy, we hope that you are all well and safe. Let’s hope that May will be the moth that finally finds us out in nature for our night sky observations. May is usually associated with the beginning of summer, a season that comes with favourable conditions for night sky observations. In this short article we’ll take you on a journey through May’s night sky!

Say goodbye to Venus

Venus still steals the show in the night sky! However, it will only be observable until mid-May, since after that it will disappear into the twilight. Thus, in the first half of the month we shall be able to spot Venus in the western sky right after sunset. Venus’ next appearance in the night sky will be in July, when it’ll be visible in the eastern sky just before dawn. So make sure you enjoy the bright Venus while it’s still possible.

Fun fact: In Greek culture Venus has the popular name of Augerinos and Aposperitis, which mean “Of the dawn” and “After sunset” respectively. This is due to the fact that Venus is visible before dawn and sometimes after sunset. As for May, you can see Aposperitis (Venus) just after sunset, while in July Augerinos will be Venus before sunrise.

By projecting the imaginary line that connects the two stars of the side of the “frying pan” and can find Polaris, the Northern Star.

Constellations and most prominent stars

A Constellation is just a group of stars in the sky. Constellations are named after mythological heroes and sagas which come from antiquity. Therefore, most of the figures represent mythical animals and heroes of Greek and Roman mythology. There is a total of 88 different constellations on the celestial sphere (northern and southern skies). Here we’ll focus on the most prominent constellations of the month.

The Great Bear and Polaris

The most famous constellation, perhaps, is Ursa Major, which in Latin means “The Great Bear”. The 7 brightest stars in Ursa Major also form what’s known as the Big Dipper, or Plough. This has a characteristic “pan” shape and during May it will become visible in the northern sky right after sunset. By projecting an imaginary line that connects the two stars of the side of the “frying pan” you can find Polaris, the Northern Star.

Fun fact:  Polaris is the only star which is always fixed at the same position on the celestial sphere, since it is located over the Earth’s rotation axis. Using Polaris we can orient ourselves, as it always points due North.

The constellation of Leo and Virgo with star Regulus and Spica

The “king” Leo and the Royal Star Regulus

We will recognize the constellation of Leo near the zenith as soon as night falls. The shape of the constellation is quite reminiscent of a lion, so the process of locating it becomes relatively easy. We can then focus on the brightest star of the constellation. This star is called Regulus and it’s actually a system of multiple stars (at least 4). The ancient Greeks attached great importance to this star, since it’s apparently located in the heart of the lion.

The constellation of Virgo with the bright star Spica

To the East of Leo you will find the constellation of Virgo. Although it is the largest constellation in the zodiac family, we have to use our imagination to see its shape. The constellation depicts a female figure that in Greek mythology was believed to be Persephone, daughter of the goddess Demeter. The very bright star Spica will make it easier for us to locate the constellation.


Mercury and Venus at a close approach of 1 degree
On May 22, Mercury and Venus will appear very close together, right after sunset. Their apparent distance will be just one degree (this is equal to the width covered by our little finger if we project it in the sky). With the naked eye it will be quite easy to locate Venus, but not Mercury. However, if we use binoculars to target Venus we will be able to see both worlds at the same time!

Also known as “the red planet”, Mars rises around 3:00 in the morning and we can locate it in the constellation of Aquarius.

It rises around 1:00 in the morning and we can spot it in the constellation of Sagittarius.

It rises around 1.30 in the morning, we can find it in the constellation of Capricorn.

The magic of the Moon

The moon always magnetises our eyes wherever it is in the night sky. The magic of the moon may lie in the fact that presents a different face every night, both when it comes to its brightness, but also its rising time. In the first days of May the Moon will be in its first quarter. As the days go by, its brightness will increase until May 7, when we will have a full moon. On this particular day, the moon will be at its perigee (the closest distance for Earth), which will give us another Supermoon. As the month progresses, we will see its brightness decreasing to its minimum on May 22 where we will have a new moon.

For advanced astronomers and astrophotographers

For the month of May, Comet C / 2017 T2 (PanSTARRS) will be in the northern sky, with a predicted magnitude of about 8. We can observe it using a telescope with a diameter of at least 150 mm. On the 22nd of the month, the comet will appear close to the galaxies M81-M82, being a special spectacle and challenge for astrophotographers.  


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