April 2023 Skies

April Skies in 2023 offer many interesting astronomical events to observe. One of the great things about April is that, for those of us in the East, we are back on the same time zone after Daylight Saving ends on Sunday, April 2nd. This means that our night shows start earlier, and we can stay out later. Additionally, April is part of the autumn season, so the nights are getting longer and colder.

During this time, the constellation Orion, known for its distinctive three-star belt, is visible in the evening sky in the west. The Southern Cross, a prominent constellation in the southern sky, can be seen all year round, and it will be visible in the evening in April.

EMU in the Sky

April is also a great time to try and find the Emu in the Sky. This pattern is created by the dark patches of the Milky Way, which form the shape of an emu, as imagined by the Indigenous people of Australia.

To see the Emu in the Sky, look towards the southern horizon on a clear, dark night. The Emu’s head is formed by the Coalsack Nebula, a dark cloud of dust and gas that is visible to the naked eye. The neck, body, and legs of the Emu are made up of the dark patches of the Milky Way, which extend from the Coalsack towards the northeast.

The Emu in the Sky holds significant cultural and spiritual meaning for many Indigenous peoples in Australia. These groups have been observing and interpreting the night sky for thousands of years, and the Emu in the Sky is often used in storytelling, mythology, and cultural practices.

According to Indigenous traditional knowledge, the Emu in the Sky is considered a creator figure who brought the land and animals into existence through song and dance. The appearance of the Emu in the Sky is also associated with the seasonal cycle of the year, particularly the onset of winter.

In some Indigenous cultures, the arrival of the Emu in the Sky is seen as a signal to begin hunting for emus, which are an important source of food and resources during the colder months. Overall, the Emu in the Sky remains a vital part of Indigenous culture, holding deep spiritual and cultural significance for many communities in Australia.

While the head and neck of the Emu can be seen in the sky as early as March, it reaches its first appearance in full length after sunset in April and May, when it is seen stretching from the South to the southeast. At this time, the Kamilaroi and Euahlayi people of Northern NSW say the Emu has legs and appears to be running.

The Moon this Month

(All times are in Australian Eastern Standard Time)

  • Full Moon:                      14:34 pm April 6
  • Last quarter Moon:      19:11 pm April 13
  • New Moon:                     14:12  pm April 20
  • First Quarter:                 07:19 am April 28

Did you know that although the exact date of Easter varies each year, there’s a definite period in which Easter can occur? This period is from March 22nd through to April 25th (in the Gregorian calendar, not the Julian calendar). Easter always occurs on the first Sunday after the Paschal Full Moon. This is the first full moon that occurs after the vernal equinox which signifies the beginning of spring in the northern hemisphere. For us this is the autumnal equinox in the Southern hemisphere.

In 2023, the equinox fell on March 20th, 2023, making the first full moon after that date to be April 6  and the following Sunday therefore is April 9.

On April 23 the Moon will be close to Venus and on April 26 it will be close to Mars in the evening sky.

On March 31, at 21:16 the Moon will be at its furthest point from us (Apogee) for this month being a 404,919 km away. On April 16 at 12:23 it will be at Perigee and a mere 367,968 km away

Perigee is the point in the Moon’s orbit when it is closest to Earth, while apogee is the point in the Moon’s orbit when it is farthest from Earth. The distance between the Moon and Earth varies throughout the month due to the Moon’s elliptical orbit, and these points of closest and farthest approach are known as perigee and apogee, respectively.

The greatest difference between high and low tide is around Full Moon and New Moon, known as spring tides or king tides. During these Moon phases, the gravitational forces of the Moon and the Sun combine to pull the ocean’s water in the same direction.

Perigean spring tides have around 5 cm larger variation than regular spring tides, while apogean spring tides have around 5 cm smaller variation than normal spring tides.

Planets in April

Several planets will be visible in the night sky in April, including Venus, Mars, Saturn, and Neptune. Jupiter will remain hidden in the Sun’s glare before returning to the morning eastern twilight sky later in the month.

Mercury is very low in the evening sky this month and mostly lost in twilight. It will not be easy to see aas it will be only a few degrees above the western horizon after sunset.

Venus is unmistakable in the early evening western sky – shining brightly as the ‘evening star’. It starts the month in Aries before moving to Taurus. It will be visible for about an hour after sunset.

On April 11 it will be close to the Pleiades or ‘Seven Sisters’ in Taurus.

Early evening sky April 11 looking west – Venus and the Pleiades (Stellarium Web)

Earth On April 20, 2023, a rare hybrid solar eclipse will take place — such eclipses occur about once every decade. Called the Ningaloo Eclipse: this hybrid solar eclipse takes its name from an Aboriginal word. The path of totality passes over North-West Cape, a remote peninsula of Western Australia. A hybrid eclipse changes from annular to total and vice versa along its path.

Unfortunately, the transition will be visible only in distant locations in the Indian and Pacific Oceans. The southern Indian Ocean, parts of Antarctica, most of Australia, Indonesia, the Philippines, most of Oceania, Southeast Asia, and the western Pacific Ocean will see at least a partial eclipse.

Never look directly at the Sun. You can seriously hurt your eyes, and even go blind. Proper eye protection, like eclipse glasses or a special solar filter, is the only safe option. Sunglasses don’t work.

What the Sun will look like near the maximum point of the eclipse

The eclipse will occur from 9:34am WST over in Exmouth where I will be viewing from the Pacific Dawn Cruise ship with Maximum eclipse starting at 12:16 and the partial eclipse will finish at 3pm WST.

Mars is visible in the north western evening sky in the constellation of Gemini. Even though it is starting to dim as it is long past opposition.

Night sky April 26 looking North and West – Moon will be close to Mars (Stellarium Web)

Jupiter is in conjunction with the Sun and remains hidden in the Sun’s glare before returning to the morning eastern twilight sky later in the month. However, those of you lucky enough to be in Exmouth for the eclipse will see Jupiter below the Sun during the eclipse.

Saturn is now rising higher in the morning sky. Located in the constellation of Aquarius it looks like  a yellow star-like object. It will remain in Aquarius until 2025.

Uranus is now lost in the evening twight and so will no longer be visible. It will remain in Aries until 2024 when it will move into Taurus. It will disappear from view as it moves towards conjunction in early May.

Neptune returns to the morning sky in Pisces as it passed through conjunction with the Sun late last month.

Meteor Showers

Finally, two meteor showers, the Lyrid and the pi Puppids, will be active in April. The Lyrids are active each year from about April 16 to 25, and the pi Puppids will be active from April 15 to 28, producing its peak rate of meteors around April 23.

Normally a small number of “sporadic” meteors can be seen each hour of a moonless night. Sporadics are likely to be seen in any part of the sky. During a shower, the number of meteors visible may increase considerably. The meteors will appear to originate from a small area of the sky, called the radiant. The spreading out from the radiant is a perspective effect due to the meteors travelling in parallel lines but as they approach the observer they appear to fan out. The shower is named after the constellation which contains the radiant. In general, the meteor trails do not start from the radiant, but a few degrees from it.

Lyrid Meteor Shower

In 2023, the likely peak morning for the Lyrids is Saturday morning, April 23. But the mornings from 19 – 23 should be good, too. The Moon should not be an issue  for a change as New Moon is on the 20th.  The Lyrids are active each year from about April 16 to 25.

Because this shower’s radiant point is so far north on the sky’s dome, the star Vega rises only in the hours before dawn, for you. It’ll be lower in the sky for us in the south so we are best to look out before dawn.

It is named Lyrid because the meteors seem to come from the constellation Lyre.

The Lyrid meteor shower has the distinction of being among the oldest of known meteor showers. Records of this shower go back for some 2,700 years. The ancient Chinese are said to have observed the Lyrid meteors falling like rain in the year 687 B.C. That time period in ancient China, by the way, corresponds with what is called the Spring and Autumn Period (about 771 to 476 B.C.), which tradition associates with the Chinese teacher and philosopher Confucius.

Comet Thatcher (C/1861 G1) is the source of the Lyrid meteors. Every year, in late April, our planet Earth crosses the orbital path of this comet which last visited the inner solar system in 1861,  and is not expected to return until the year 2276.

Pi-Puppid Meteor Shower

The pi Puppids are a meteor shower associated with the comet 26P/Grigg-Skjellerup. The ?-Puppid meteor shower will be active from 15 April to 28 April, producing its peak rate of meteors around 23 April.

The meteor stream was viewable around April 23 but only in years around the parent comet’s perihelion date, the last being in 2003. However, as the planet Jupiter has now perturbed the comet’s perihelion to beyond Earth’s orbit it is uncertain how strong the shower will be in the future.

Clear Skies