This Week’s Sky at a Look, April 12 – 20

April 12, 2019 - Comment

The Moon crosses Gemini because it reaches first quarter. . . . . .after which it crosses Leo whereas waxing gibbous. Friday, April 12 • First-quarter Moon (precisely so at three:06 p.m. EDT). Early this night, the Moon shines excessive within the southwest with Pollux and Castor to its higher proper and brighter Procyon decrease

Moon and stars, April 10-12, 2019

The Moon crosses Gemini because it reaches first quarter. . .

Moon under Leo, April 14-15, 2019

. . .after which it crosses Leo whereas waxing gibbous.

Friday, April 12

• First-quarter Moon (precisely so at three:06 p.m. EDT). Early this night, the Moon shines excessive within the southwest with Pollux and Castor to its higher proper and brighter Procyon decrease left of it, as proven right here.

Saturday, April 13

• At the moment of yr, the 2 Canine Stars stand vertically aligned across the finish of twilight. Look southwest. Far beneath the Moon this night is Procyon in Canis Minor. Good Sirius, in Canis Main, is an analogous distance beneath Procyon.

Later within the night the association strikes decrease and rotates a bit clockwise, as seen right here. The Canine Stars are following Orion down towards making their seasonal exits within the southwest.

• Use binoculars tonight to search for M44, the scattery Beehive Star Cluster in Most cancers, roughly three° to the correct of the glary Moon (as seen from the longitudes of North America).

Sunday, April 14

• The gibbous Moon shines higher proper of Regulus this night.

• The large, brilliant Winter Hexagon nonetheless fills the sky to the southwest and west on the finish of twilight. Begin with sensible Sirius within the southwest, the Hexagon’s decrease left nook. Excessive above Sirius is Procyon. From there look even larger for Pollux and Castor, rightward from Castor to Menkalinan and brilliant Capella, decrease left from there to Aldebaran, decrease left to Rigel means down on the backside of Orion, and again to Sirius.

Monday, April 15

• Arcturus shines brightly within the east these evenings. The Massive Dipper, very excessive within the northeast, factors its curving deal with lower-right towards it.

Arcturus varieties the sharp finish of a protracted, slim kite asterism shaped by the brightest stars of Bootes, the Cowherd. The kite is presently mendacity on its facet to Arcturus’s left. The pinnacle of the kite, on the far left, is bent barely upward. The kite is 23° lengthy, about two fists at arm’s size.

Tuesday, April 16

• As Arcturus climbs the japanese sky these evenings, equally brilliant Capella is descending excessive within the northwest. They stand at precisely the identical peak above your horizon at some second between about 9 and 10 p.m. daylight-saving time, relying totally on how far east or west you reside in your time zone.

How precisely are you able to time this occasion on your location? Like the whole lot constellation-related, it occurs four minutes earlier every evening.

Wednesday, April 17

• Vega, the intense “Summer season Star,” rises within the northeast proper across the finish of twilight relying in your latitude.

Precisely the place must you look ahead to it to come back up? Spot the Massive Dipper nearly overhead within the northeast. Take a look at Mizar on the bend of its deal with. In the event you can see Mizar’s tiny, shut companion Alcor (binoculars make it straightforward), comply with a line from Mizar by way of Alcor all the best way all the way down to the horizon. That is the place Vega makes its look.

Thursday, April 18

• The Moon this night, practically full, shines between Spica to its decrease proper and brighter Arcturus about 4 instances farther to the Moon’s higher left (for North America).

Friday, April 19

• Full Moon (precise at 7:12 a.m. Jap Daylight Time). This night search for Spica a couple of fist and a half to the Moon’s higher proper, and brighter Arcturus about twice as far to the Moon’s higher left.

Saturday, April 20

• About an hour after darkish now, the Pointer stars forming the top of the Massive Dipper’s bowl level straight down towards Polaris, three fists at arm’s size beneath them. Face north and look means up.


Need to turn out to be a greater astronomer? Be taught your means across the constellations. They’re the important thing to finding the whole lot fainter and deeper to hunt with binoculars or a telescope.

That is an out of doors nature interest. For an easy-to-use constellation information masking the entire night sky, use the large month-to-month map within the heart of every concern of Sky & Telescope, the important information to astronomy.

Jumbo Pocket Sky Atlas cover

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and tons of of telescopic galaxies, star clusters, and nebulae amongst them. Proven above is the Jumbo Version for simpler studying within the evening. Pattern chart.

When you get a telescope, to place it to good use you will want an in depth, large-scale sky atlas (set of charts). The fundamental normal is the Pocket Sky Atlas (in both the unique or Jumbo Version), which exhibits stars to magnitude 7.6.

Subsequent up is the bigger and deeper Sky Atlas, plotting stars to magnitude eight.5; practically thrice as many. The following up, as soon as you already know your means round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) and Uranometria (stars to magnitude 9.75). And skim methods to use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, reminiscent of Sue French’s Deep-Sky Wonders assortment (which incorporates its personal charts), Sky Atlas Companion by Sturdy and Sinnott, or the larger Evening Sky Observer’s Information by Kepple and Sanner.

Can a computerized telescope change charts? Not for newbies, I do not assume, and never on mounts and tripods which are lower than top-quality mechanically (which means heavy and costly). And as Terence Dickinson and Alan Dyer say of their Yard Astronomer’s Information, “A full appreciation of the universe can not come with out creating the talents to seek out issues within the sky and understanding how the sky works. This data comes solely by spending time beneath the celebs with star maps in hand.”

Jupiter, Ganymede, Europa and double shadows, March 25, 2019

Europa and Ganymede, the smallest and largest of Jupiter’s 4 traditional Galilean moons, have been each casting their shadows onto the planet when Damian Peach used the 1-meter Chilescope to take this picture on March 25th at 9:31 UT. South is up. The extraordinarily excessive decision right here reveals many floor markings on Ganymede. Click on and open in a brand new tab for full-size view.

Venus-Mercury problem continues. Venus (magnitude –three.9) and far fainter Mercury (about magnitude +zero.2) are each very low within the brightening daybreak. Choose up Venus close to the east horizon about 20 or 25 minutes earlier than dawn. Then use binoculars or a wide-field telescope to search for little Mercury 4½° all the way down to its decrease left.

Mars (magnitude +1.5, in Taurus) glows within the west after nightfall. Begin with Orion within the west-southwest, and look to the correct from there for the orange pair of Aldebaran and Mars. Mars, barely dimmer, is the one on the correct or, later within the week, higher proper. They continue to be about 7° aside.

Examine the colours of those two similar-looking, however completely completely different objects. To me Mars seems to be very barely redder.

And bear in mind — nowhere in human expertise however astronomy are issues so completely different than they seem.

Jupiter (magnitude –2.three, on the ft of Ophiuchus) rises within the southeast round midnight or 1 a.m. daylight-saving time. It shines pretty excessive within the south earlier than the start of daybreak, in order that’s one of the best time to look at it telescopically. Arrange your scope about two hours earlier than your native dawn time.

At the moment you will discover Antares to Jupiter’s decrease proper, and the dimmer Sagittarius Teapot an analogous distance to Jupiter’s decrease left. The Teapot is concerning the dimension of your fist at arm’s size.

As well as, Saturn (magnitude +zero.6, in Sagittarius) might be glowing pale yellow-white about 25° to Jupiter’s left or decrease left.

Uranus and Neptune are out of sight within the glare of the Solar.


All descriptions that relate to your horizon — together with the phrases up, down, proper, and left — are written for the world’s mid-northern latitudes. Descriptions that additionally rely on longitude (primarily Moon positions) are for North America.

Jap Daylight Time (EDT) is Common Time (UT, UTC, or GMT) minus four hours.


Audio sky tour. Out beneath the night sky along with your earbuds in place, hearken to Kelly Beatty’s month-to-month podcast tour of the heavens above. It is free.


“I appear to have been solely like a boy enjoying on the seashore, and diverting myself in every now and then discovering a smoother pebble or a prettier shell than atypical, while the good ocean of reality lay all undiscovered earlier than me.”
— Isaac Newton, 1642–1727



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