Saturn rules this month! And that’s very unusual, because Saturn is the faintest and least noticeable of the bright planets. So why is Saturn top dog in August, 2015? Only because Mercury, Venus, Mars and Jupiter – the other planets visible to the eye alone – all are hiding in the glare of evening or morning twilight throughout this month. Maybe they’re just not wanting to be upstaged by this August’s awesome Perseid meteor shower. Follow the links below to learn more about August planets.
Brilliant Venus disappears in sunset glare by mid-August. Venus is the brightest planet and third-brightest sky object overall, after the sun and moon. When it’s visible, it’s very, very prominent in our sky. But it’s not easily visible this month. In August 2015, Venus moves out of the evening sky and into the morning sky. This happens officially on August 15, 2015, when Venus will pass nearly 8 degrees south of the sun as seen from our earthly perspective. If you are blessed with an unobstructed horizon in the direction of sunrise, you’ll probably see Venus low in the east, about an hour before sunrise, sometime during the last week of August, 2015.
The real challenge is to see Venus in the west at evening dusk in early August. At mid-northern latitudes, Venus sets roughly 45 minutes after the sun, and at temperate latitudes in the Southern Hemisphere, Venus sets over an hour after sunset in early August.
In other words, the Southern Hemisphere has the advantage over the Northern Hemisphere for catching Venus in the evening sky in the first part of the month.
Southerly latitudes might even see Venus with Jupiter and Mercury toward the end of the first week of August, though only for a brief while after sunset. Click here to find out more. Thereafter, Venus and Jupiter rapidly sink into the sun’s glare and disappears from the evening sky, while Mercury remains an evening object for the rest of the month. But Mercury, too, is better from Earth’s Southern Hemisphere.
Bright Jupiter lost in sunset glare in early August. Jupiter shines more brilliantly than any star. It’s the second-brightest planet after Venus. Both Venus and Jupiter will transition over into the morning sky in August, 2015.
In late June and early July, Venus and Jupiter staged their closest conjunction until August 27, 2016, and displayed a second – though less close – conjunction in the evening sky on July 31 – the same date as this year’s Blue Moon.
Now these two brilliant worlds are heading for their third and final conjunction of the year in the morning sky on October 26, 2015.
By a wonderful coincidence, as Venus and Jupiter showcase their final conjunction of the year – on October 26 – Venus will reach its greatest eastern (morning) elongation from the sun.
Moreover, the year’s closest grouping of three planets – Venus, Mars and Jupiter – will also take place on October 26. That’s a big deal because the next planetary trio won’t occur again until January, 2021!
If you live in the Southern Hemisphere or the northern tropics, you might catch the conjunction of Jupiter and Mercury in the evening sky after sunset on August 6 or 7. Have binoculars on hand for the conjunction will take place near the horizon and in the murk of evening dusk. It’ll be their closest conjunction since May 22, 2012; and closer one won’t happen again until November 27, 2018.
Normally, if you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto. In August of 2015, however, Jupiter’s moons will have a hard time competing with the sun’s glare.
These moons circle Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we get to view a number of mutual events involving Jupiter’s moons through a high-powered telescope. Click here or here or here for more details.
Click here for a Jupiter’s moons almanac, courtesy of Sky & Telescope.
Mercury up in evening twilight, best from Southern Hemisphere. Mercury is our solar system’s innermost planet and always stays near the sun in our sky. Mercury passed out of the morning sky and into the evening sky in July, 2015. Mercury will remain an evening object for an unusually long time – till the very end of September, 2015. It will be a real challenge to catch Mercury and Jupiter in conjunction at the end of the first week of August – especially from northerly latitudes.
For the Southern Hemisphere, August and September present Mercury’s best appearance in the evening sky for all 2015. By mid-August, Mercury will set about 90 minutes after the sun. By the month’s end, Mercury will set a whopping two hours after sunset, and Mercury’s great evening apparition will continue throughout the most of September – in the Southern Hemisphere and the northern tropics.
Those residing at northerly latitudes aren’t nearly as lucky. At mid-northern latitudes, Mercury sets a maximum of one hour after the sun in late August. Try scanning with binoculars in the glow of evening dusk.
At temperate latitudes in the Southern Hemisphere, this world actually sets after the end of evening twilight from about mid-August to mid-September. Look for Mercury over the sunset point on the horizon as dusk gives way to darkness. Click here to find out Mercury’s setting time in your sky, and for the time at which astronomical twilight ends.
Binoculars are always recommended to enhance sky views! Click here for recommended almanacs. They can help you know when Mercury sets in your sky.
Mercury will stay in the evening sky until September 30, 2015. Then it’ll pass into the morning sky, to give the Northern Hemisphere its best morning apparition of Mercury for the year.
Saturn easily visible from nightfall until late night. Throughout August 2015, the golden planet Saturn comes out at nightfall. Depending on where you live worldwide, Saturn sets at late evening or after midnight.
Binoculars don’t reveal Saturn’s gorgeous rings. For that, you need a small telescope.
Saturn’s rings are inclined at about 24o from edge-on in August 2015, exhibiting their northern face. A few years from now, in October 2017, the rings will open most widely, displaying a maximum inclination of 27o. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27o by May, 2032.
Earth and Mars travel in orbit as similar speeds (Earth at 18 miles per second, Mars at 15 miles per second). So it takes awhile for Mars to come out of the sun’s glare, and, when it finally does so, Mars always lingers in our predawn sky for several months. That’s going to be the case in northern autumn, 2015.
In August, most likely – although Mars is technically up before sunrise – you likely won’t see the Red Planet. Try using the moon to guide your eye to Mars before sunrise on August 11 and 12. Binoculars will be helpful!
Mars will be easier to see in late August and September. By that time, Mars will rise sooner before sunrise and be higher up at dawn. Plus the dazzling planet Venus will be fairly close to Mars, and Venus can serve as your guide to the Red Planet.
What do we mean by visible planet? By visible planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.
Bottom line: Saturn is the dominant planet in August, 2015. Four of the five visible planets – Mercury, Venus, Mars and Jupiter – hide in the glare of evening or morning twilight.