We are now in the month of April and the spring equinox is behind us. The clocks have gone forward and the Sun now sets at 20.00 at that start of the month. This still gives loads of time to get out and observe but also means we can enjoy longer evenings.
The last two months have been very poor in terms of naked eye objects with most of the planets lost to the glare of the Sun. Things start to improve now but some of them will still be difficult to see and also you will need to get up very early to see them.
The spring constellations are now prominent in the sky so now is a good time to familiarise yourself with them. The best time to look will be around the middle of the month when the Moon is new.
Sun and Moon
|Date||Sunrise (Irish Time)||Sunset (Irish Time)|
Mercury starts in the morning sky this month. It draws closer to the Sun, becoming impossible to see for a few days around the 19th. After this, it reappears in the evening sky. Your best chance to see it is to look for it close to the horizon in the west as the sky darkens after sunset towards the end of April. On 25th April, Mercury will be very close to Venus in the evening sky.
Venus reappears in the evening sky in April. It will be visible low on the western horizon after sunset. It will become easier to see as the month progresses and close to a very thin crescent moon on the evening of the 12th and close to mercury on the evening of 25th.
Mars is well past its best but is still visible in the April sky. It will appear as a salmon – pink coloured star in the west after Sunset. It will be a lot dimmer than it was in previous months.
Jupiter is back in our sky this month but you will need to get up very early as it rises only 70 mins before sunrise. Look low in the southeast.
Similar to Jupiter, you will need to get up very early to see Saturn. Visible in the morning sky around 70 mins before sunrise in the southeast.
Stars and Constellations
The above sky chart, from heavens-above.com is for 23:00 on 15/04/2021. You can click on the chart to open a new tab and bring you to Heavens Above. On this website you can generate a custom chart for the time and date you wish. The winter constellations are fading in the west to be replaced by the spring constellations.
In the west after sunset is the constellation of Gemini (the twins), Auriga (the charioteer) and Perseus. To the northwest are Cepheus (the house), Cassiopeia (the queen), Andromeda and Pegasus (the flying horse). Andromeda is the location of the Andromeda galaxy which is the furthest object that can be seen with the naked eye. Although, you will need very dark skies to see it. Andromeda and the Milky Way galaxy are headed for a collision and will collide in an estimated 4.5 billion years.
Over in the southwest have the spring constellations. You will see Leo (the lion) and the plough is now rising higher in the sky. Taking the curve of the handle of the plough and following it toward the eastern horizon will bring you to a bright red star called Aldebaran. This is the brightest star in the constellation of Bootes. Although this constellation represents a herdsman it actually looks more like a kite. It’s always nice to see this constellation appearing. It will be high in the sky in the summer and is a sign that we are heading out of winter and into spring. Finally, to the east of Bootes is the constellation of Hercules. You can identify this by its distinctive “Keystone” shape. To the north is Lyra (the harp) and Cygnus (the swan).