For the second month in a row, it doesn’t truly gets dark during July. For the sky to be completely dark, the Sun must get at least 18 degrees below the horizon and this only happens on the last 2 days of July from Ireland. Jupiter and Saturn both reach opposition this month. This is when the planet is the opposite side of the sky to the Sun and is when the planet appears largest for this period of observation. Again, this month you should keep an eye out for noctilucent clouds which can be seen some evenings shining in the north after sunset and before sunrise. I have another post about noctilucent clouds and the link is below:
https://thescienceshed.com/2020/05/29/noctilucent-clouds/
Sun and Moon
| Date | Sunrise (Irish Time) | Sunset (Irish Time) |
|---|---|---|
| 01/07/2020 | 05:01 | 21:55 |
| 15/07/2020 | 05:16 | 21:44 |
| 31/07/2020 | 05:40 | 21:21 |
| Moon Phase | Date |
|---|---|
| Full Moon | 05/07/2020 |
| Third quarter | 13/07/2020 |
| New Moon | 20/07/2020 |
| First quarter | 27/07/2020 |
Planets
Mercury
Mercury is hard to see as it is so close to the Sun. Make sure the Sun has set before looking for it. It is possible to see Mercury before sunrise, in the northeast for the second half of the month. From around the 16th July on, look for Mercury in the hour before sunrise, close to the northeast horizon.
Venus
Venus has returned to the morning sky and can be seen shining very brightly in the northeast before sunrise. A small telescope will show a crescent shape. Venus passes through the Hyades open cluster this month. On the 17th July at 3.00am, look northeast and you will see Venus very close to the bright star Aldebaran, the Hyades and the crescent Moon.
Mars
Mars is visible in the southeast. It will look like an orange star. Look for it in the southeast after around 01.45am at the start of the month and from around midnight at the end of the month.
Jupiter
Jupiter is visible is the south. It is very bright this month as it approaches opposition on July 14th and appears close to Saturn which is dimmer. Look for it in the south from around 11.30pm onward at the start of the month or from sunset at the end.
Saturn
Saturn is visible in the south and rising earlier each night. It appears close to Jupiter but is dimmer. Look for it in the south from around 11.30pm onward at the start of the month or from sunset at the end. Saturn reaches opposition on 20th July.
Stars and Constellations
The above sky chart is for 23:00 on 15/07/2020. 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 of Leo (the lion), Bootes (the herdsman) and Virgo (the virgin) still take prominence overhead early in the night. But they have now moved west slightly. An interesting fact about the constellation of Virgo is that the galaxy M87 is located in Virgo. M87 contains the supermassive black hole which astronomers managed to image the shadow of in 2019.
Look out for Cygnus (the swan), Lyra (the liar) and Aquila (the eagle). The brightest stars in these constellations are Deneb, Vega and Altair and they make up the Summer Triangle. By around midnight there are right overhead. Hercules (the hunter) is also overhead at this time of year.
In the south at this time of year is the constellation of Scorpius (the scorpion). This is the direction of the centre of our galaxy, the Milky Way. It never rises very high in the sky from Ireland, but if you look in the direction, from a dark location you should be able to make out that it is almost misty or milky with stars.
Over in the east you can see Pegasus (winged horse in Greek mythology), Andromeda (Princess of Ethiopia) and Perseus (the hero).
Paul Smith 