Special to CosmicTribune.com, April 8, 2025

Excerpts from weekly Sky&Telescope report.

SUNDAY, APRIL 6

■ The Big Dipper stands high in the northeast these evenings, tipping over to the left dumping water. Its handle plus the two stars of its bowl closest to the handle form a broad, rough arc. To the right of the arc, not too far from its focus, shines a lone 3rd-magnitude star. That’s Cor Caroli, the brightest star of Canes Venatici. It’s a beautiful telescopic double, magnitudes 2.8 and 5.6, separation 19 arcseconds. They’re spectral types A0 and F2, respectively.

Also in CVn is one of the brightest deep-red carbon stars in the sky. Y Canum Venaticorum, also known as La Superba, varies between magnitudes 4.6 and 5.9. Currently it’s visual mag 5.3. Matt Wedel calls it “arguably the finest carbon star for binocular users” in his Binocular Highlight column in the April Sky & Telescope, page 43. Carbon stars like this are so red because we see them through red filters: their atmospheres are rich in diatomic carbon, C₂ , a red gas.

MONDAY, APRIL 7

■ The Moon is in Leo with Regulus 5° or 6° below it this evening. Gamma Leonis, less bright, is a bit farther left or lower left of the Moon. Those are the two brightest stars of Leo’s Sickle. The entire Sickle extends upper left from Regulus by a little more than a fist at arm’s length.

To see its stars better through the moonlight, cover the Moon with your hand. Or use two fingertips, one for each eye. Close one eye and position a fingertip on the Moon. Then switch eyes and position another fingertip on the Moon. Open both eyes.

TUESDAY, APRIL 8

■ Now the Moon shines below Regulus, Gamma Leonis, and Leo’s Sickle.

■ The huge, bright Winter Hexagon is still in view early after dark, filling the sky to the southwest and west. It’s the biggest well-known asterism in the sky.

Start with brilliant Sirius in the southwest. It’s 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, with Mars to their left). Go lower right from Castor to Menkalinan and then bright Capella, lower left from there past Jupiter to Aldebaran, lower left to Rigel at the bottom of Orion, and back to Sirius.

The Hexagon is somewhat distended. But if you draw a line through its middle from Capella to Sirius, the “Hexagon” is fairly symmetric with respect to that long axis.

WEDNESDAY, APRIL 9

■ In late twilight or thereabouts, 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). Those are the two brightest stars in the sky at this time.

But Capella is a very close runner-up to Arcturus! Spot it high in the northwest.

THURSDAY, APRIL 10

■ Right after dark, Orion is still fairly well up in the southwest in his spring orientation: striding down to the right, with his belt horizontal. The belt points left toward Sirius and right toward Aldebaran and, farther on, the Pleiades. Jupiter grabs your eye above Aldebaran.

■ Mars, Pollux, and Castor very high in the west form a straight line tonight. Watch it begin to bend in the coming days.

FRIDAY, APRIL 11

■ At this time of year, the two Dog Stars stand vertically aligned around the end of twilight. Look southwest. Brilliant Sirius in Canis Major is below, and Procyon in Canis Minor is about two fists above.

The bright Moon pairs with Spica on Saturday evening. (Note: The Moon here is always drawn three times its actual apparent size, and it’s always positioned for an observer near the center of North America.)

SATURDAY, APRIL 12

■ Full Moon (exact at 8:22 p.m. EDT). The full Moon of April always shines in the vicinity of Spica. This year they’re especially close together, as indicated above.

The Moon will occult Spica for most of South and Central America and the southernmost tip of South Africa. Map and timetables.

SUNDAY, APRIL 13

■ Vega, the bright “Summer Star,” rises in the northeast late these evenings. How early or late depends on your latitude and also on your longitude within your time zone.

Exactly where should you watch for Vega 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 will make its appearance!

  April 6-13: The full Moon and Spica on April 12, The Sky