Still image from a four-minute video showing you how to see the beautiful planetary alignments in late March. –Click image to go to the video on YouTube.
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”
Chart of the area surrounding the constellations Andromeda, Triangulum, and Aries, as seen from Denver in mid-December at 9:00 PM, viewing just south of the zenith (nearly “straight up”). Telrad circles are shown centered on 6 Trianguli (6 Tri), one of this month’s targets. As an aid to finding 6 Tri, note how the circles center on the imaginary line running from Almach to Beta Tri, and how the outermost circle touches another imaginary line running between Gamma and Alpha Tri. –Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. (Tap on image above for larger version.)
The Solar System
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”
Looking just west of south in Denver at 9:00 PM on October 15th. Telrad circles are included for scale; their center is about 30° above the horizon. Note that with 3rd- and 4th- magnitude stars in its outline, most of Capricornus will likely not be visible to the naked eye under city lights. –Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. (Tap on image above for larger version.)
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”
Viewing almost straight up in Denver at 9:00 PM on September 15th. Telrad circles are shown positioned to put NGC 6871 near the center of a finderscope field, after centering on Eta (η) Cygni and slewing toward Sadr. From here, a 1° slew to the southeast (perpendicular to the swan’s “neck,” or the line from Sadr to Albireo) will get the cluster in or near your low-power eyepiece field. Note position of Eta Cygni at trailing edge of the 4° Telrad circle. Also note the dotted line showing the alignment of M29, Sadr, and Omicron1 Cygni. The Cygnus Rift, illustrated above, is an area of dust and gas that obscures the Milky Way’s stars and nebulae. It is the same type of structure as the “dust lanes” often seen in edge-on galaxies. –Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. (Tap on image above for larger version.)
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”
Viewing southward in Denver at 10:00 PM on August 15th. Telrad circles are centered on the Lagoon Nebula, M8; note position of the Trifid Nebula, M20, just inside the 4° circle, and thus in most finderscopes’ field of view (remember that M20 will be shown at the bottom of an inverted finderscope view). Vesta passes between b Ophiuchi and C Ophiuchi this month, as illustrated by the thin curving arrow at center-right. Look at last month’s chart to get a feel for this area of Ophiuchus, located right above Scorpius (just off this month’s chart at bottom-right). –Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. (Tap on image above for larger version.)
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”
