The solar system gets its ducks in a row – Sky & Telescope
Like a peacock spreading its feathers, the five brightest planets in the solar system will unfurl in a magnificent spectacle at dawn until early July. Even more amazing, they will be in it the right order outward from the Sun beginning with Mercury at the eastern horizon followed by Venus, Mars, Jupiter and ending at Saturn. Standing under the spread will feel like looking out the window of spaceship Earth at our place in the cosmic order.
This rare event last occurred in the morning sky in December 2004. In the evening sky, we saw similar planetary lines in October 1997 and September 1995, but Mercury’s elongation at these times was no more than 10°, limiting sight to clear vision. attentive observers in tropical latitudes. For American skywatchers, the last major similar broadcast was in July 1957. Ouch, I was barely four years old!
I encourage you to get up early at least one morning for a look. Invite friends. Bring the kids. There will be multiple viewing options, but both better opportunities occur on June 24 (described above) and June 26, when Venus and the thin-filament Moon meet in conjunction. While not a once-in-a-lifetime event, the next opportunity won’t be until March 2041. Call me impatient, but I’m not making any assumptions about the future.
Alignment is essentially a naked eye event – the only requirements are clear to partly cloudy skies and a clear east-northeast horizon. That said, I highly recommend bringing a pair of binoculars to help unearth Mercury, which will hover low in the solar glow a few degrees above the horizon for mid-north and mid-south latitude observers. . Assuming a clear view and haze-free air, I think you’ll see Mercury unaided. But a backup pane will ensure you won’t be short-circuited on a planet. The other four will be much easier to spot.
You’ll want to get out a little early to get your bearings and find a comfortable place to sit to take in the views. An hour and 15 minutes before local sunrise is perfect. A lake, agricultural field, or high vantage point with a clear east-northeast horizon is an ideal location. Venus will be bright and low, with Mercury poised to rise at that time. The five planets will be best visible, depending on your latitude, from about 1 hour to 40 minutes before sunrise. Since this time is essential for planning, use this sunrise calculator to find out when the sun rises for your location.
Since many of us will want to photograph the span, you may want to do some pre-scouting to include suitable foreground scenery. On June 20, the pack covers about 102° of sky, increasing to 116° by the end of the month. For a full-frame DSLR, you’ll need at least a 12-14mm lens – with horizontal fields of view of 104° and 112°, respectively – to squeeze them all in. Cropped sensor cameras require even shorter focal lengths. Since these lenses aren’t cheap, a better alternative would be to take multiple shots of the scene with a standard lens and combine them into a single image using an imaging program like Paint (which comes with Windows 10/11), Mac OS Photos, or Photoshop. Check YouTube for videos showing how it’s done.
Your creative hand will also be needed during post-processing due to the vast difference in lighting between the darker southern sky, where Mars, Jupiter and Saturn reside, and the bright belly of the eastern horizon, where the inner planets.
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Don’t forget to include the Earth in the programming! You can do this by using the waning moon as a proxy. Or just look around and take in the scenery. If you’re a completist, you’ll also want to research Uranus and Neptune. They’re up there too, even if they screw up the order. Both are visible in binoculars or a small telescope. And while we’re at it, let’s include 4 Vesta, a representative of the main asteroid belt. The maps below provide the positions of these three additional objects.
How beautifully these five tiny lights demonstrate the essential flatness of the solar system. Looking up, you can practically see the ecliptic etched into the sky. When pointed out, even a neophyte will quickly grasp the “shape” of our neighborhood and the place of the Earth within it. And while flat earthlings will argue with you to the death about our planet’s sphericity or lack thereof, at least we can all agree this month that the solar system is as flat as a thin-crust pizza.
Read more about this and other celestial events this month in the June 2022 issue of Sky & Telescope.