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What’s In May’s Night Skies


Mercury will reappear from the Sun’s glare in the evening sky in the Taurus (The Bull) Constellation in the middle of the second full week of May and will move into the Gemini (The Twins) Constellation by the end of the month. Mercury will set at 06:02 pm (AWST) on Friday the 15th of May and by the end of the month it’ll set at 06:47 pm (AWST). Venus can be found in Taurus (The Bull) Constellation this month and at the start of May it’ll set at 07:36 pm (AWST). It will be lost to the Sun’s glare by the end of month.

Mars will start the month of May in the Capricornus (The Sea Goat) Constellation as an orange dot and will move into the Aquarius (The Water Bearer) Constellation in the second week of the month. The planet will rise at 00:32 am (AWST) at the beginning of the month and by the end of the month, it’ll rise at 00:11 am (AWST). Jupiter, the king of the planets can be still be found in the Sagittarius (The Centaur with a Bow) Constellation this month. At the beginning of the month, it’ll rise at 10:33 pm (AWST) and by the end of May, it’ll rise at 08:34 pm (AWST). Saturn will be in the Capricornus (The Sea Goat) Constellation during the month of May rising at the beginning of the month at 10:57 pm (AWST) and by the end of the month it’ll rise at 08:57 pm (AWST).

Uranus reappears in the morning sky at end of the first full week of May in the Cetus (The Sea Dragon) Constellation and it’ll rise at 05:59 am (AWST) on Saturday the 9th of May. By the end of the month it’ll rise at 04:38 am (AWST). Neptune, the last planet in our Solar System can be found in the early morning sky between the Aquarius (The Water Bearer) and Pisces (The Fish) Constellations for the whole of May. The planet will rise at 02:49 am (AWST) at the beginning of the month and by the end of the month at 00:54 am (AWST)

Mercury and Venus on the 15/05/20 at 06:00 pm. Image Credit: Stellarium Mars and Neptune on the 15/05/20 at 04:00 am. Image Credit: Stellarium
Jupiter and Saturn on the 15/05/20 at 02:00 am. Image Credit: Stellarium Uranus on the 15/05/20 at 06:00 am. Image Credit: Stellarium

Conjunctions and Occultation

Conjunctions involve object(s) in the Solar System and/or more distant objects, such as a star. It’s an apparent phenomenon in which multiple objects which aren’t close together appear close in the sky and it’s caused by the observer’s perspective. An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.

  • 02/05/20 – Conjunction of the Moon and Regulus (Where to look)
  • 05/05/20 – Conjunction of the Moon and Spica (Where to look)
  • 08/05/20 – Conjunction of the Moon and Antares (Where to look)
  • 12/05/20 – Alignment of the Moon, Jupiter and Saturn (Where to look)
  • 13/05/20 – Conjunction of the Moon, Jupiter and Saturn (Where to look)
  • 14/05/20 – Alignment of the Moon, Mars, Jupiter and Saturn (Where to look)
  • 15/05/20 – Conjunction of the Moon and Mars (Where to look)
  • 16/05/20 – Conjunction of the Moon, Mars and Formalhaut (Where to look)
  • 22/05/20 – Conjunction of Mercury and Venus (Where to look)
  • 26/05/20 – Conjunction of the Moon, Pollux and Castor (Where to look)
  • 29/05/20 – Conjunction of the Moon and Regulus (Where to look)

Astronomical Events This Month:

The Eta Aquarids:

Starting early in the morning of the 6th of May the Eta Aquarids meteor shower be their peak. The shower is active from 19th of April through to the 28th of May, and its normal meteor per hour rate can vary between 10 – 20 meteors per hour for Perth. Unfortunately, the Moon will be near its Full Moon phase so you’ll see a reduced number of meteors this year.

The cause of the Eta Aquarids is the famous Comet Halley, named after Astronomer Edmund Halley, who first determined in 1705 that the comet was periodic. The Eta Aquarids are one of two meteor showers caused by Comet Halley, with the other shower being October’s Orionids. Halley’s orbit around the Sun takes 75 years with next entering the inner system again in 2061.

The meteors will seem to appear from the constellation Aquarius which gives the meteor shower its name. Aquarius will appear in the sky over the Perth hills around 11:30 pm so you should go out around 4:00 am and give your eyes 15 minutes to fully adjust to the lighting conditions and look between North and North East. While it’s always best to find a nice park or a large open space for best viewing of a meteor shower, you can go out to our front or back yard and still get a good view.

The Eta Aquarids on the 06/05/20 at 04:00 am. Image Credit: Stellarium Meteors from the Eta Aquarids.

Things to Look at This Month

Eight-Burst Nebula:

The Eight-Burst Planetary Nebula (NGC 3132) also known as the Southern Ring Nebula is a bright planetary nebula in the constellation Vela. It’s 2,000 light-years away from us and is 0.4 light-years across. The name “planetary nebula” refers to the round shape and in reality, nothing to do with planets but due to it appearing like a planet. The round shape is actually huge shells of gas ejected a star as it nears the end of its life and are expanding away from the central star at a speed of 9 miles per second.

Images of the nebula shows two stars close together within the nebulosity with the white dwarf that created the nebula being the fainter of these two stars. The white dwarf is at a temperature of 100,000 K and has now blown off its layers. The intense ultraviolet radiation comes of the white dwarf is making the nebula fluoresce brightly.

The Eight-Burst Nebula on the 15/05/20 at 09:00 pm. Image Credit: Stellarium The Eight-Burst Nebula. Image Credit: Hubble Heritage Team (STScI/AURA/NASA/ESA)
Centaurus A:

Centaurus A or NGC 5128 is an elliptical galaxy that we see edge-on. The galaxy is the fifth brightest galaxy in the sky and one of the closest radio galaxies to earth. It’s between 10 to 16 million light years away from us and It can be found in the Centaurus constellation. The galaxy itself has a diameter of 60,000 light years making it 40% smaller than our galaxy and at its centre it has a supermassive black hole with a mass of ~55 million suns. It was discovered in 1826 by Scottish astronomer James Dunlop from Parramatta, in New South Wales.

It’s a starburst galaxy meaning that it is undergoing a period of intense star formation compared to an average galaxy. Studies have confirmed that this high rate of star birth is caused by a collision between itself and a smaller spiral galaxy. The bright central bulge and the dark dust lane can be easily viewed using an amateur telescope however a larger telescope is required to view greater detail and contrast. Centaurus A is an extremely bright radio object, X-Rays in particular. The central supermassive black hole is the source of this with two long radio jets extending well beyond the visual bounds of the galaxy.

Centaurus A on the 15/05/20 at 09:00 pm. Image Credit: Stellarium The Centaurus A Galaxy - Image Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)
The Jewel Box:

An open cluster the Jewel Box can be found very close in the Crux (Southern Cross) Constellation, the Jewel Box is located some 6,440 light years away from Earth and is 14 light-years across. The cluster contains just over 100 stars, and with an estimated age of its stars being just 14 million years, this star cluster is one of the youngest clusters that we’ve found. The Jewel Box cluster also has some of the brightest stars in the Milky Way galaxy. These stars are supergiants and the red, white and blue stars in the centre of the cluster look very much like the lights of a traffic light.

Jewel Box on the 15/05/20 at 09:00 pm. Image Credit: Stellarium The Jewel Box in perspective - Image credit: ESO, NASA/ESA, Digitized Sky Survey 2 and Jesús Maíz Apellániz
Eta Carinae and the Carina Nebula:

Variable brightness and Colour, Eta Carinae is one of the most remarkable stars in the heavens. When we say “Eta Carinae” we refer to the star itself which for Perth is a circumpolar star (We see the star all year round) and not the nebula.

Eta Carinae is 100 times the Sun’s mass and 4 million times brighter, those this brightness has been unstable with the star being recorded over the past 300 years between magnitude -0.8 which is as bright as Canopus and +7.9. It’s a star that’s sometimes in the news as it’s expected to become a supernova within the next 1 million years and will be a spectacular sight when it occurs, being visible by day and possibly bright enough to read by at night.

Eta Carinae is very likely a binary star with the smaller partner orbiting in a highly elliptical orbit of 5.5 years. The Carinae Nebula (NGC 3372), which surrounds Eta Carinae, is a large, bright star-formation region which has produced a number of very massive stars including Eta Carinae. At around 260 light years the Carina Nebula is around 7 times the size of Great Orion Nebula, but due to its greater distance, it only spans twice the width. There are many O-type stars, young (~2 million years), hot and bright that energise the entire Eta Carinae nebulae.

Carina Nebula on the 15/05/20 at 09:00 pm. Image Credit: Stellarium The Carina Nebula. Image Credit: Roger Groom Eta Carinae. Image Credit: NASA
Omega Centauri:

Omega Centauri or NGC 5139 is the largest and brightest globular cluster of 180 in Milky Way and is the second largest known, with only Mayall II in the Andromeda Galaxy being larger coming ins about twice its mass. The Globular cluster is located in Centaurus Constellation and it’s a naked eye ‘star’ and clearly visible in binoculars as a ‘fuzzy blob’. Omega Centauri contains at least 3 million stars and the cluster has a diameter of roughly 150 light-years and the stars are roughly 12 billion years old. The average distance between the stars at the centre is around 10% of a light year or more than 100 times the diameter of our solar system. It may be a dwarf galaxy that has been captured and disrupted by the Milky Way galaxy and measurements of its star movement by Hubble has indicated that a black hole may be located at the core of the cluster.

Omega Centauri on the 15/05/20 at 09:00 pm. Image Credit: Stellarium Omega Centauri - Image Credit & Copyright: Joaquin Polleri & Ezequiel Etcheverry (Observatorio Panameño en San Pedro de Atacama)

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