Jasper Dark Sky Festival

This Week’s Sky: August 22 – 29

Venus meets Jupiter and the Moon visits the Hyades.

Dickinson-Saturn,Mars,Antares Aug21 2016r

SkyNews editor emeritus Terence Dickinson captured this view of Saturn, Mars and Antares (along with the Sagittarius Milky Way) on August 21. The two planets will line up with the star this week. (See August 23/24 below.)

All Week

Monday eve, SSW

The view facing south-southwest on Monday evening, one hour after sunset.

The evening sky is host to two pairs of planets, but seeing one set requires an unobstructed western horizon and binoculars. The challenging pair is Venus and Jupiter—two planets heading in opposite directions. Jupiter is wrapping up its current apparition and sets roughly an hour after the Sun. Venus, on the other hand, is at the start of what will be a lengthy evening appearance. The brilliant planet will gain elevation over the coming months, but with painful slowness. (For more on Jupiter and Venus, see August 27, below.) The easy planetary duo are Mars and Saturn, which lie in Scorpius near first-magnitude Antares. Neither planet is at its best—both are quite low in the south-southwest as twilight fades—but they are the most rewarding solar system targets for telescope users. Saturn is always and arresting sight thanks to its magnificent rings, but Mars is well past its opposition date and has shrunk to about 11 arc minutes diameter.

August 23/24

Mars, Saturn, Antares

Facing south-southwest, one hour after sunset on August 24.

Mars, Saturn and Antares line up in a nearly straight row in the south-southwest and are a lovely naked-eye sight. Binocular users will discover that Mars and Antares fit easily in one field of view. Mars and Saturn, separated by a little more than four degrees, will also fit into any binocular field. Those with wide-angle binos can try framing the full trio, which spans six degrees.

August 24

Last-quarter Moon occurs at 11:41 p.m., EDT. However the lunar disc doesn’t rise until after midnight.

August 25


The Moon in the Hyades as seen in 10×50 binoculars.

This morning the first-quarter Moon passes through the Hyades cluster in Taurus, occulting several reasonably bright stars as it drifts eastward. This will be a fun event to view in a small telescope or binoculars.

August 27

Venus and Jupiter

Venus and Jupiter at their closest, as viewed in a small telescope at 66×.

Venus catches up to Jupiter low in the west during early twilight this evening. The two bright planets (magnitudes –3.8 and –1.7, respectively) will be at their closest at 6:32 p.m., EDT, when they’re separated by a scant 4 arc minutes. By the time the Sun sets, they will have moved apart a couple of arc minutes, but still remain close enough to be viewed together in a telescope at fairly high magnification—a very rare sight. If you have a telescope equipped with a GoTo mount, you should be able to see them in daylight when they’re at their absolute closest. Venus will be a relatively easy catch, but Jupiter is much more ghostly.

Weekend Stargazer


The last-quarter Moon is a fine telescopic sight and this week passes through the Hyades cluster in Taurus. Photo courtesy Gary Seronik

The August 26 – 28 weekend is a fine one for enjoying the last-quarter Moon, favourably situated in Taurus. The best time to view it is in the dawn sky when its highest and relatively free from the distorting effects of our atmosphere.

Watching the terminator slowly sweep cross the lunar surface is one of the great joys of Moon observing. It’s interesting to note how familiar features look different during sunset illumination (when the Moon’s phase is waning) as opposed to sunrise (when the phase is waxing). So, even though the same swath of lunar real estate is on the terminator at last quarter as at first quarter, everything appears altered. To fully appreciate the effect, pick one or two features and examine them at both first and last quarter. The Apennine Mountains region is a good choice, as are the prominent craters Ptolemaeus, Alphonsus and Arzachel. By viewing this attractive trio under different lighting conditions over many nights, you can develop a better sense of each crater’s true morphology.

At SkyNews we love to read about your experiences and see your photos. You can share them with us by e-mailing skynews@skynews.ca.

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