In spite of nasty viruses and all kinds of other misbegotten issues, the sky still performs its celestial dance–and we now have an opportunity to see the planets embrace as they perform a pre-dawn planetary conjunction–that is, two or more planets will line up closely from our point of view here on Earth. Mars and Jupiter will draw close on the morning of March 19, and even closer on Friday, the 20th. After that, they’ll continue to dazzle early risers–especially since Saturn is also nearby, and for part of the dance, at least, our Moon makes a cameo as a beuatiful crescent…
I have created a video covering the next several days’ planetary action, so you can see how these events will look–and which planet is which! It’s a little over four minutes, and I hope it inspires you to get out and look for yourself–here’s the YouTube link: https://www.youtube.com/watch?v=0zqeHokQCs8
If you’ve heard about the November 11 Transit of Mercury (visible 6:39 AM – 11:04 AM, Mountain Standard
Time, here in Denver), you may have a simple question: “What is it, and why
is a transit a rare event?” The “what” is quick to answer; the “why” takes a
bit longer, but isn’t hard to understand.
During a transit of Mercury, we see Mercury’s silhouette
pass across the face of the Sun. It’s very much the same idea as a solar eclipse
(when the Moon passes in front of the Sun), except that Mercury is so much
farther away that it hardly covers the solar disk—all we see (through a telescope
set up for safe solar viewing) is the planet’s “little black dot” move across
the Sun over several hours.
If we could watch this event while looking down from a vantage high above our solar system, we’d see Mercury, the Earth, and the Sun arranged in a fairly straight line, with Mercury between the Earth and Sun (see Chart 1, below). Continue reading “The Mercury Transit Explained”
Mercury ended November lost in the solar glare, but as it sweeps rapidly through its orbit, it will become increasingly visible as a pre-dawn target. After about the first week of December, the planet will sit almost 10° above the southeastern horizon at 6:30 AM, roughly 40 minutes before dawn. (By then, it will look like a fat crescent in telescopic views.) A week later, Mercury reaches its widest angle, as we see it, from the Sun (known as “greatest elongation”), and sits slightly higher at the same hour, brightening by about a half-magnitude as well. After that, the planet will appear closer to the Sun each day. Look for a close conjunction with Jupiter on the morning of the 21st, when the two planets will lie within a degree of each other.
Late-November views of Venus were spectacular, even with the naked eye—the planet’s sheer brilliance in a dark sky made a 5:30 AM rise worthwhile. (Venus was so bright, it made it hard to recognize a nearby, seemingly wan star for what it really was: 1st‑magnitude Spica.)
Happily, the views continue in December—though the planet’s brightness diminishes slightly and the disk appears a bit smaller, it still presents a terrific target, Continue reading “December Skies 2018”
Welllllll… We had a planet-rich summer, but many of the planetary observational opportunities are going away or will do soon. At the same time, we’re in a great position for deep-sky targets, with late-summer objects still in play, and winter targets, like Orion, becoming visible to observers in the wee hours. The earlier onset of night helps, too. Here’s what’s up for October: Continue reading “October Skies 2018”
If you’ve been watching the sky after sunset in August, then you’ve likely noticed the striking vista of four bright planets—Venus, Jupiter, Saturn, and Mars—lined up from southwest to southeast. Even without a telescope, their sweep makes a memorable view, and the arrangement will continue well into September Continue reading “September Skies 2018”
If you follow the planets, you’re likely aware that Marsis just past opposition at the beginning of August, and thus more or less at its biggest and brightest for the year. Dust storms, though, have blanketed the planet, cloaking surface details that should’ve been visible even in moderately sized telescopes. Recent NASA reports suggest Continue reading “August Skies 2018”