The sky, April 1-7: Jupiter, due West at twilight

Special to, April 1, 2024

Excerpts from weekly Sky&Telescope report.


■ The huge, bright Winter Hexagon is still in view early after dark, filling the sky to the southwest and west. Start with brilliant Sirius in the southwest, the Hexagon’s lower left corner. High above Sirius is Procyon. From there look higher upper right for Pollux and Castor (lined up nearly horizontal), lower right from Castor to Menkalinan and then bright Capella, lower left from there to Aldebaran, lower left to Rigel at the bottom of Orion, and back to Sirius.

■ Last-quarter Moon tonight (exactly so at 11:15 p.m. EDT). The Moon doesn’t rise until around 3 a.m. daylight-saving time Tuesday morning, depending on your location. Once it’s fairly well up in the southeast just before dawn begins, you can see that it’s right near the handle of the Sagittarius Teapot, which sits horizontally at that time.

Crescent Moon with low, difficult Mars and Saturn in the bright dawn, April 5-6, 2024


■ This is the time of year when the dim Little Dipper juts to the right from Polaris (the Little Dipper’s handle-end) during late evening. With the Moon gone from the evening sky, the subtle Little Dipper stands out as well as it ever does.

The much brighter Big Dipper curls over high above it, “dumping water” into it. They do the reverse water dump in the fall.

■ Vega, the bright “Summer Star,” rises in the northeast these evenings. How early or late depends on your latitude and on your longitude within your time zone. Exactly where should you watch for it to come up? Spot the Big Dipper almost overhead in the northeast. Look at Mizar at the bend of its handle. If you can see Mizar’s tiny, close companion Alcor (binoculars show it easily), follow a line from Mizar through Alcor all the way down to the horizon. That’s where Vega makes its appearance.


■ Castor and Pollux shine together west of the zenith after dark. Pollux is slightly the brighter of these “twins.”


■ The bright star very high in the west-northwest during and after dusk is Capella. Its pale-yellow color matches that of the Sun, meaning they’re both about the same temperature. But otherwise Capella is very different. It consists of two yellow giant stars orbiting each other every 104 days.

Moreover, for telescope users, it’s accompanied by a distant, tight pair of red dwarfs: Capella H and L, magnitudes 10 and 13.

On Friday and Saturday mornings, the thin waning Moon can help locate difficult Mars and Saturn low in bright dawn. Bring optical aid! The visibility of faint objects low in the brightening sky is greatly exaggerated here.


■ Shortly after nightfall around this time of year, Arcturus, the bright Spring Star climbing in the east, stands just as high as Sirius, the brighter Winter Star descending in the southwest (for skywatchers at mid-northern latitudes).

These are the two brightest stars in the sky at the time. But Capella is a very close runner-up to Arcturus! Spot it high in the northwest.

Jupiter under the Pleiades and Aldebaran at dusk, April 5, 2024.

Mercury has faded and set. Watch the Pleiades settle a little closer to Jupiter until they both become lost in twilight late this month.


■ More Sirius doings: The two Dog Stars stand vertically aligned around the end of twilight. Sirius in Canis Major is the bottom one, and Procyon in Canis Minor is high above it.


■ High above the Big Dipper late these evenings, nearly crossing the zenith, are three pairs of dim naked-eye stars, all 3rd or 4th magnitude, marking the Great Bear’s feet. They’re also known as the Three Springs (or Leaps) of the Gazelle, from early Arab lore. They form an east-west line that lies roughly midway between the Bowl of the Big Dipper and the Sickle of Leo. The line is 30° (three fists) long. See the evening constellation chart in the center of the April Sky & Telescope.

According to the ancient Arabian story, the gazelle was drinking at a pond — the big, dim Coma Berenices star cluster — and bounded away when startled by a flick of Leo’s nearby tail, Denebola. Leo, however, seems quite unaware of all this, facing the other way.

Another version sees Coma Berenices as Leo’s extended tailtip and the pond as formed by stars in Ursa Major.


Mars, magnitude +1.2 in Aquarius, rises after dawn begins. Try for it just above the east-southeast horizon about 45 minutes before sunrise. Binoculars help.

Jupiter, magnitude –2.1 in Aries, is the bright “star” shining due west in twilight, not very high. It sinks lower after dark and sets around 10 p.m. It’s the only easy planet in the entire sky now.

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