This Week’s Sky: October 24 to 31

All Week

1-hour-after-sunset-ssw — The view facing south-southwest, one hour after sunset.

Most of the planetary action at the moment is in the evening sky. Saturn is slowly losing its battle with twilight and hangs less than ten degrees above the horizon one hour after sunset. Venus is even lower (about five degrees), but is sixty times brighter (magnitude –3.9 versus 0.6). This means you can spot Venus much earlier when it’s higher up. Last of the evening planets is Mars. Shining at magnitude 0.3, the red planet is keeping slightly ahead of twilight’s glow as it drifts eastward through Sagittarius. Mars will continue to linger in the evening sky well into next spring. Meanwhile, the morning sky’s sole planet is Jupiter. The magnitude –1.7 object rises nearly two hours before the Sun, but is still a few weeks away from being a good telescopic sight.

October 27

sw-45-minutes-after-sunset — Facing southwest, 45-minutes after sunset.

This evening Saturn, Venus and Antares line up in the southwest as darkness falls. A touch more than seven degrees will separate Saturn (on top) from Antares (on the bottom). The two planets will be quite easy to spot, but Antares, being both the lowest and faintest of the trio, will present a challenge.

October 28

moon-and-jupiter-bino-view — The Moon and Jupiter together as seen in 10×50 binoculars.

A razor thin crescent Moon rises along with Jupiter this morning. For observers in eastern Canada, the celestial duo will be separated by only one degree. By the time they rise over western Canada, the Moon will have shifted eastward and lie nearly twice as far from the planet. The pairing will be a fine naked-eye sight and very striking in binoculars or a small telescope.

October 29

This evening Venus and Saturn are closest together in the sky as the brilliant evening “star” passes just three degrees south of Saturn. You’ll have no trouble finding Venus soon after sunset, but Saturn will take a while longer to appear to your unaided eye. Binoculars will help show the ringed planet above Venus in twilight.

October 30

The Moon is new today at 1:38 p.m., EDT.

Weekend Stargazer

sw-weekend — Summer constellations dominate the southwest sky at the end of evening twilight. (Click on the chart for a full-size view.)

The end of October is an interesting time for sky watchers. Although the cooler autumn weather is a reminder that winter is coming, some of the stars overhead suggest that summer isn’t quite over yet. On the moonfree October 28 – 30 weekend you can still enjoy many of the constellations that have been around for months. For example, at nightfall the Summer Triangle (consisting of Vega, Altair, and Deneb) is well positioned high in the southwest. If you get out early enough, you can explore the Sagittarius Milky Way before it descends into the southwest horizon. Even Hercules and its magnificent globular cluster, M13, are visible halfway up the western sky.

This extended celestial summer is a result of our northerly latitude. Although the constellations that dominated from June through August now set earlier, our nights are growing longer at the same time. Cygnus the Swan benefits most richly from this effect. It first climbs into view in the midnight eastern sky in April and can be seen lingering in the northwest even in February! (You can read more about this effect in David A. Rodger’s article here.) But don’t wait any longer: take some time this weekend to enjoy the treasures these constellations hold before cloudy weather dictates the terms their of surrender.