It’s autumn and the Sun is now setting before 7pm which means more time for observing. This is exaggerated even more at the end of the month, when, on the 31st of October summer time ends and the clocks go back 1 hour.
October nights can get very chilly so it’s time to start taking out the heavy clothes again. Wrapping up and keeping warm can be the difference between enjoying a night’s astronomy and coming inside early.
Jupiter will be the main feature in the sky during October this year. The king of the planets will be prominent in the sky throughout the month. If you have a small telescope or binoculars, it’s the perfect time to take a look at the four largest moons of Jupiter which are Europa, Ganymede, Calisto and Io,
Sun and Moon
| Date | Sunrise (Irish Time) | Sunset (Irish Time) |
|---|---|---|
| 01/10/2021 | 07:26 | 19:01 |
| 15/09/2021 | 07:52 | 18:28 |
| 31/10/2021 | 07:22 | 16:53 |
| Moon Phase | Date |
|---|---|
| New Moon | 06/10/2021 |
| First quarter | 13/10/2021 |
| Full Moon | 20/10/2021 |
| Third quarter | 28/10/2021 |
Planets
Mercury
Mercury appears in the morning sky in the second half of October. From around the 20th October, look for it about 60- 90 mins before the Sun rises. Make sure the Sun hasn’t risen before looking and stop looking as soon as it rises. It will be low in the southeast.
Venus
Venus is visible after sunset in the southwest during October. The chance of seeing it will increase as the month goes on. At the start of the month, it will set around 60 mins after the Sun but by the end this will have increased to about 90 mins. Venus will be very bright which should help it stand out in the twilight.
Mars
Not visible this month.
Jupiter
Jupiter remains prominent this month. It will be high in the South as the sky darkens during October. If you have a small telescope or binoculars, it’s the perfect time to take a look at the four largest moons of Jupiter which are Europa, Ganymede, Calisto and Io,
Saturn
Saturn is visible to the west of Jupiter, it will also be high in the south as the sky darkens. It will be the dimmer of the two stars.
Stars and Constellations
The above sky chart is for 23:00 on 15/10/2021. 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 spring constellations are gone and the winter constellation are appearing on the eastern horizon after sunset.
High overhead 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.
In the south at this time of year, is the constellation of Pisces (the fish) and Aquarius (the water bearer). Mars is also in this area of the sky. Over in the east we have the winter constellations rising. You will see Taurus (the bull) which has a distinctive “V” shape and beside it the Pleiades or M45.
Paul Smith 