Astro Bob: Wait a minute now — EIGHT planets in a row?
There are more than five planets at dawn. Hidden in the lineup are Uranus, Neptune and the asteroid Vesta. Oh, and Earth, too.
Did you know that there are three more solar system members hiding in dawn's bright planet lineup? Uranus, Neptune and Vesta, the brightest asteroid, are also part of that graceful arc. You'll need only a little optical aid to spot them. Normally, a pair of steadily held 7x50 or 10x50 binoculars would show all three, but dawn light will be a limiting factor.
Vesta will shine at magnitude 6.7 (easy in binoculars) and Neptune at 7.9 (more challenging but doable). Both are located between Jupiter and Saturn. To make sure you see them try getting out there a little earlier, about two hours before sunrise when the sky is still dark. If you wait until dawn is underway a small telescope will be necessary.
Uranus is a special case. It's located between Mars and Venus and fairly bright at magnitude 5.8 but too low above the horizon before dawn for a good view. I suggest you wait until about an hour and a half before sunrise, when the planet climbs to around 10 degrees. Twilight will still be weak at that time, which makes me fairly confident you'll see the remote planet in binoculars. If not, then a small telescope will nab it and the others.
The five bright planets have special appeal not only because they're easy to see but grouped in order of increasing distance from the sun. Mercury, the innermost planet, shines low in the east, followed by Venus, the moon (a proxy for Earth), Mars, Jupiter and Saturn. Like cosmic tiki lamps, they festoon the sky from from northeast to south.
Uranus, Neptune and Vesta are clearly out of order in terms of distance, but hey, you can't have everything. Besides, how often can you see all eight planets — and a representative from the main asteroid belt — in one swipe? I plan to get to my viewing location early to spot Vesta, Neptune, Saturn, Jupiter and Mars in a darker sky then wait to watch the others rise. I have a pair of 10x50 binoculars ready to go and a small refracting telescope as backup.
Again, the most important thing is finding the right location. You'll need a wide-open view to the east as close to the horizon as possible to see Venus and Mercury. Venus is plenty bright, but Mercury will be immersed in the twilight glow. In some locations haze could also be an issue. All the other naked-eye planets are higher up and more forgiving. If you miss a morning, no worries. The planets will be out to enjoy into early July.
Take this opportunity to get acquainted with interplanetary neighborhood. The lineup beautifully illustrates just how flat the solar system really is. If it weren't, the planets would be strung out willy-nilly in the sky. But no. They're neatly arranged in a line because the Earth also lies in the same flat plane.
The solar system is like a huge, thin-crust pizza. As we look outward across its flat expanse both ahead and behind us, the planets appear to cycle around the sky on a single, narrow "highway" called the ecliptic, which defines the plane of the solar system. For now and for joy, they've even lined up in correct order, something we won't see again until March 2041.
"Astro" Bob King is a freelance writer for the Duluth News Tribune.