What Can I See in the Sky in March 2021?

The month of March is upon us which means it’s officially spring. The spring equinox occurs on 20th March. This is the time when the Sun crosses the celestial equator and the length of the day and night are equal. After this the nights will be shorter than the days. In Ireland, the clocks also go forward on 28th March so this has the effect of pushing darkness out by another hour. The Sun sets at 20:00 by the end of the month which still leaves plenty of time to get out and look at the sky while still enjoying the bright evening.

I try to ensure that everything in the guide is suitable for observation without equipment, but unfortunately this month is a little short on naked eye sights. The planets of Venus, Saturn and Jupiter, that featured in the night sky during the autumn and winter are now too close to the Sun to be seen easily. There is the opportunity to try and spot the very thin crescent Moon on the evening of the 14th March. On that evening try looking west after sunset and you might be able to see the Moon only 1.8% illuminated. This isn’t easy so if you don’t manage it that evening you can try the following evening when the Moon is still only 5% illuminated.

The spring constellations are now becoming more 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

DateSunrise (Irish Time)Sunset (Irish Time)
Sunrise and sunset times (Dublin)
Moon PhaseDate
Third quarter06/03/2021
New Moon13/03/2021
First quarter21/03/2021
Full Moon28/03/2021
Moon phases (Dublin)



Mercury is in the morning sky early this month, but it very hard to see. Look 30 mins before sunrise at the start of the month in the south east, very close to the horizon.


Too close to the Sun to be visible.


Mars has past its best but is still visible in the March sky. It will appear as a salmon – pink coloured star and will have already risen when the sky gets dark. It will start off high in the southwest and move towards the west as the evening goes on. It has gotten a lot dimmer than it was in the autumn and will continue to get dimmer this month. If you have a small telescope you will also notice the size of the disk is getting smaller as the days go by. This month Mars passes very close to the Pleiades star cluster, which you can see with your naked eye.


Visible in the morning sky just before sunrise but will be very difficult to see.


Visible in the morning sky just before sunrise but will be very difficult to see.

Stars and Constellations

Sky chart for 15th March 2021 23:00 credit: Heavens above

The above sky chart, from heavens-above.com is for 23:00 on 15/03/2021. 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.

Visible in the west will be Orion (the hunter). Most people are somewhat familiar with this constellation and will be able to pick out Orion’s belt. You may also be able to pick out the Orion nebula just below the Orion’s belt. If you start from here and make a line using the 3 stars of the belt you can follow them down to a bright star called Sirius. Sirius is in the constellation of Cannis Major (the dog). This is actually the brightest star in the sky and is really beautiful.

If you follow the line of the belt in the other direction you will come to a red star called Aldebaran. This is the brightest star in the constellation of Taurus (the bull) which has a distinctive “V” shape. Continuing along this line we come to a misty patch of stars called Pleiades or M45. This is a star forming region 1,344 lightyears away.

Above this 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 south and east we have the spring constellations rising. 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.

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