What’s in the sky for August 2021 – Ian Bradley

Astronomy weather forecast sites

They are customizable to your location – the links below are set to Kendal.

This satellite view I find quite useful as it shows the cloud cover for the previous 212 hours or so. This lets you have an idea as to what cloud is coming … switch to infra-red to view the clouds at night.

Nice resources

Sky Notes for August – Ian Bradley

The Moon

Phase August September
3rd Quarter 1st
New Moon 8th 6th
1st Quarter 15th 13th
Full Moon 22nd 20th
3rd Quarter 29th 28th

ISS visible passes

No ISS passes visible before August 28th. Have a look at Heavens Above for a Kendal location for detailed timings.

The Planets

Mercury is at superior conjunction, on the far side of the Sun from the Earth, on August the 1st before moving into the evening sky. However, it will be very difficult to see as it will be very low in the sky.

Venus is prominent in the evening sky and 36° east of the Sun at sunset on August 15th at magnitude -4.0. Phase about 80% so should look fairly round in a telescope with an angular diameter of 14”. You will need a good clear unobstructed western horizon to be able to see it. On August 11th, Venus will be about 5° west of a lovely crescent Moon.

Mars at magnitude 1.8 is on a line roughly midway between Venus and the Sun. It sets around 21:16 on August 15th. It is rather tiny compared to Venus with an angular diameter of only 4”. Very difficult at the moment.

Jupiter Meridians
August Time
1st 02:40
8th 02:09
15th 01:30
22nd 01:07
29st 00:32

Jupiter reaches opposition on August 19th. It rises about 9pm mid-month and is very obvious at magnitude -2.9. It isn’t that high in the sky, typically maximum 20° but is still a gorgeous sight in a telescope with its moons spread out in a line. Best time to look is when Jupiter is within an hour or so of due south as it will be at its highest altitude. On August 22nd, the full Moon will be nearby (10° east).

If you are lucky, you may see a moon appear, disappear or even better, transit the disk. Using the Jupiter almanack you can identify and find the times of these events and also the visibility of the Great Red spot.

Saturn is also visible all night but again low in the sky. Opposition on August 2nd. Much fainter than Jupiter at magnitude 0.2 but still an easy naked eye object showing a yellowish hue. A telescope is required to see its rings. The best viewing is as it nears the meridian, about 1 hour before Jupiter. With a telescope, you might also spot some of its moons, Titan is the most obvious one. See Saturn’s moons in motion.

Uranus is visible at magnitude 5.7 nearly all night in August, when it rises around 2300 BST, and transits about 0600. Clearly best to look in the early hours of the morning.

Neptune is visible at magnitude 7.8 throughout the night when it rises around 21:30 BST, and transits about 0300 mid-month. Another early hours object.

Meteor showers

Perseids meteor shower – peak August 12th/13th but active from active from 16th July to 23rd August . Usually one of the better meteor showers to observe, producing up to 150 meteors per hour at its peak. It is produced by comet Swift- Tuttle. Visible throughout the night but probably best just before dawn on the 13th. The shower tends to have a large number of fast bright meteors, some leaving persistent trails. The waxing moon will set early evening, providing dark skies for the rest of the night. But try the nights before and after, too, from late night until dawn.

Draconids meteor shower – October 8th/9th – radiates from the Head of Draco and worth looking for a day either side. Because Draco is almost overhead in the evening, this shower tends to be best in the evening rather than morning. But it is an oddball as generally it doesn’t produce that many meteors per hour but is prone to intense outbursts of 100’s per hour some years. The Moon isn’t an issue as moonset is around 7pm.

Orionids meteor shower – October 21st. The Moon is full so probably not worth looking out for. At best 10 to 20 per hour and usually better early morning. Tend to be fast-moving meteors which occasionally leave persistent trains and sometimes bright fireballs which might be visible over the bright moonlight.

Leonids meteor shower – November 17th/18th.  Another full moon. One of the better shows with the radiant inside the reverse question mark, The Sickle, of Leo. Typically, 10 to 15 meteors per hour but does have occasional very strong showings. Best after midnight.

Sky Charts – 15th August at 2100 BST

Looking up, south is at the bottom.

Dominated by the asterism of the Summer Triangle and the Milky Way. These three very bright stars that form the Summer Triangle, Vega, Deneb and (just off the diagram) Altair are good for getting your bearings. Although very prominent on the charts, the Milky Way will be easier to see clearly later in the year with darker skies. A new Moon on the 8th gives a good photo opportunity for this.

There are lots of Messier objects to see:

  • Planetary nebula:
    • M57, the Ring Nebula, in Lyra which appears as a fuzzy green donut in the eyepiece
    • M27 the Dumbbell Nebula is also pretty good
  • Globular clusters:
    • M3
    • M13
    • M92
  • Galaxies:
    • M51
    • M101

Just less than 2° from Vega is The Double-Double, Epsilon (ε) Lyrae, a binary star in binoculars, but with a telescope, each of these two stars is seen to be a double star itself. And don’t forget the rather pretty and colourful double star at the head of Cygnus, Albireo β-Cygni. The primary is a lovely amber orange at magnitude 3.1 whilst the secondary is a blue-green at magnitude 5.1. The separation is 35” so easily separable in a small telescope.

Click for a larger version.

Looking south

The galactic centre in Sagittarius is visible if you’ve a good southern horizon. Antares is the bright naked eye star just above the horizon. Great photo opportunity for the Milky Way around new Moon, August 8th.

  • Globular clusters:
    • M10
    • M12
  • Stellar clusters:
    • The Eagle Nebula M16
    • M11
  • Planetary nebula: M27 The Dumbbell Nebula

Click for a larger version.

Looking east

The Milky Way and its luxurious star fields and clusters runs right through Cassiopeia, Cygnus and Aquila. The open cluster M52 in Cassiopeia is a nice binocular object. Lower down are two globular clusters, M15 and M2.

Click for a larger version.

Looking west

Telescopically, it might be worth trying for M81 and M82 in addition to M51.

Click for a larger version.

Looking north

Still rather bright in this direction as the Sun isn’t that far below the horizon. The Andromeda Galaxy M31 clearly visible in binoculars. The star clouds of the Milky Way are ‘busy’. The Triangulum Galaxy M33 is still rather low early in the evening.


Next Observing Evening

Given the current situation regarding coronavirus, observing evenings can not occur.