By Peter Gudgeon
AUGUST: Jupiter and Saturn dominant the evening sky
Sunday 2nd August 2 (dim) comets just over 1º apart (a photo opportunity ?).
Wednesday 12th August Perseid Meteor Shower peak
I hope most of you, or those that wanted to, caught a glimpse of the comet 2020 F3 (NEOWISE) last month. It was only discovered at the end of March so came as a pleasant surprise, although not the easiest of objects, with its limited period of visibility before/after sunrise/sunset, and then often playing a game of hide and seek with the clouds, but compared to other recent comet forecasts this exceeded expectations. It is now an early evening object, but fading rapidly as August progresses.
For many, the main interest this month will be Jupiter, closely followed by Saturn, both prominent in the early evening sky. We also have the Perseid meteor shower that peaks in the second week of August, when the Moon is in its last quarter, so not too much interference from Moonlight. While for those with the right equipment, and a bit of luck, there is an opportunity to capture a photo containing 2 comets.
August 3 Full Moon
August 11 Last quarter
August 19 New Moon
August 25 First quarter
Planets (all times are Local Spanish time)
Mercury:- Mercury starts the month being just visible before sunrise, but passes behind the Sun on the 17th. After that it becomes an evening object but is no more than 1 degree above the horizon after sunset by the end of August.
Venus:– Venus is visible in the mornings before sunrise, it starts to rise approx 3:45. On the 13th, Venus reaches its greatest western distance from the Sun.
Mars:– Mars does not rise until 20 minutes past midnight at the start of August, but is rising earlier each day, so that by the end of August it rises at 10:40 pm. So best observed a few hours before sunrise.
Jupiter:– Jupiter is visible in the evening sky all this month, being the unmistakable bright object in the SE sky once the Sun has set. By the end of the month it will have advanced so the it is due south at 10:35 pm. It never gets higher than 30º above the horizon. It sets around 5:30am at the start of August but by the end of the month it will have set by 3:30am.
Saturn:– Saturn, slightly dimmer and behind Jupiter, about 7º to the left of Jupiter. Saturn will set approx 30 minutes after Jupiter. As well as admiring its rings, see if you can also spot Saturn’s brightest moon, 8th magnitude Titan, see chart to the right. Note:- The positions shown here are inverted, to show how it should appear when seen through an astronomical telescope.
Uranus:- Uranus starts the month not rising until 1 am, but by the end of August rises nearer 11:00 pm. Again, best seen a few hours before sunrise. By the end of the month it reaches its highest, about 65º above the southern horizon just before 6am, when the sky is starting to brighten.
Neptune:- Neptune rises before midnight (11pm at the beginning of August advancing to 10pm by the end of the month). It reaches a maximum altitude of 45º above the southern horizon around 4:50 am at the start of the month moving to 2:45 am by the month’s end.
C/2019 U6 (Lemmon), and C/2017 T2 (PanSTARRS)
These 2 comets are of photographic interest only, both being near magnitude 10, but deserve a mention as on the evening of 2nd August these 2 faint comets will be just over 1º apart (RA 13h 33m, Dec +18º), offering photographers a rare opportunity to capture 2 comets in the same photo (Good luck to anyone who tries).
C/2020 F3 (NEOWISE)
This comet is now well past its best, although it remains above our North/Western horizon just after Sunset for all of this month. It will be gradually be getting dimmer, and each evening moving slightly lower and further west. It is expected to be around magnitude 5.5 at the beginning of August, but dim rapidly to something nearer magnitude 9 the end of the month.
The main meteor shower this month is the Perseids, active from 17th July to 24th August producing its peak around the 12th August.
The radiant of this shower is circumpolar, so this shower is active throughout the whole night, but is best placed around 8am, indicating that the highest rate of visible meteors are likely to be before dawn on Wednesday 12th and again after dusk on the 12th. It is estimated (if you are lucky) that you may see over 130 meteors per hour during these peaks. The Moon will be near its last quarter so should not be a problem in the evening.
Another shower this month is the Aurigids, active from 28th August to 5th September but is expected to have its peak on the night of Monday 31st August/1st September. As the radiant does not rise above the horizon until 0:30am, the peak activity is best seen in the early morning of 1st September but even then, the maximum rate is only expected to be up to 5 meteors an hour.