Comet ZTF is fading and receding into the distance. But the Moon is gone from the early evening sky after February 7th, with the comet very high overhead in Auriga heading toward Taurus. It reached magnitude 5.0 around the beginning of the month. By February 10th it will probably be down to about 6.2.

Comet C/2022 E3 (ZTF on Jan. 21, 2023),
Comet ZTF E3, imaged on January 21st by Pepe Chambó of Valencia, Spain, using an 8-inch short-focus reflector. Note the narrow, straight ion tail and the broad, curved dust tail.

The comet is heading almost due south after its brush past the Little Dipper. See Bob King's article Understanding the Tails of Comet ZTF, with a finder chart for use in February. (On that chart, the comet symbols are labeled with the dates for evening in North America, not the UT date.)

If/when the comet becomes too faint for that chart to suffice, use the more detailed one in the February Sky & Telescope, page 48 (where the dates are for 0:00 UT; subtract one day from those to get the North American civil date.)

On the evening of February 8th, with the sky now moonlessly dark for an hour or so after the end of twilight, the comet will be passing close by Iota Aurigae and probably t about magnitude 6.0. After that, the Moon rises about an hour later each evening affording dark views of the receding comet high overhead for the next two weeks as it moves south across Taurus toward the shield of Orion.

On the evenings of February 10th and 11th the comet will be less than 2° from Mars. By then it will probably be about mag 6.2, some 250 times fainter than Mars but still waiting for your binoculars or telescope.


■ The nearly full Moon shines just below Pollux and Castor during evening. It forms a straight line with them when the stars come out over the eastern Canadian Maritimes. The line becomes slightly curved by the time of dusk for the rest of the continent.


■ The Moon is farther below Castor and Pollux in the evening now. It makes a very broad, gentle arc with Procyon to its right and bright Sirius far off to the right or lower right of Procyon.


■ Full Moon (exactly full at 1:29 p.m. EST). The Moon, in Leo, rises in the east-northeast within a few minutes of sunset. Once the Moon is well up after dark, you can see it forming an isosceles triangle once again with Regulus and Algieba, the two brightest stars of Leo's Sickle glimmering through the moonlight. Regulus is about a fist below the Moon. Algieba (Gamma Leonis) is a fist to the Moon's lower left.


■ Orion is now high in the southeast after dark. Left of it is Gemini, headed up by Castor and Pollux at far left. The stick-figure Twins are still lying on their sides.

Well below their legs is bright Procyon. Standing 4° above Procyon is 3rd-magnitude Gomeisa, Beta Canis Minoris, the only other easy naked-eye star of Canis Minor. The Little Dog is seen in profile, but only the ourline of his back and the upper part of his head. Procyon marks his rump, Gomeisa is the back of his neck, and two fainter stars just above that are the top of his head and his nose. Those last two are only 4th and 5th magnitude, respectively. He's a little dog indeed. Binoculars help through light pollution.


■ At this time of year, if you live near latitude 40° north, twilight lasts 1½ hours after the Sun sets. The end of twilight is when you want to be all set up and ready to observe Comet ZTF in a moonless sky for the first time in a week.

It's in Auriga overhead, a bit faded since it was closest to Earth last week. Use the finder chart covering these dates at the bottom of Circumpolar Comet ZTF (C/2022 E3) is Here! Turn the chart upside down, and ignore the horizon, for the Northern Hemisphere's view. The dates on the comet symbols are for 0:00 Universal Time, which in North America falls on the evening of the previous date. Or use the more detailed printed chart in the February Sky & Telescope, page 48.


■ Spot the big, bright, equilateral Winter Triangle in the southeast, lower left of the Moon. Sirius is its brightest and lowest star. Betelgeuse stands above Sirius by about two fists at arm's length. To their left shines Procyon.

Can you discern their colors? Sirius (spectral type A0) is cold white, Betelgeuse (M2) is yellow-orange, and Procyon (F5) is white with just a slight touch of yellow.

■ The inside of the Winter Triangle is mostly occupied by the front half of Monoceros, the dim Unicorn. Now that the Moon is out of the early-evening sky, pick out some telescopic sights here using Matt Wedel's Binocular Highlight column and chart in the February Sky & Telescope, page 43. Fourth-magnitude Delta Monocerotis is a wide optical double. Five degrees west of it is the open cluster NGC 2301, sixth magnitude. A telescope shows "a ragged line of stars trending roughly north-south across the center of the cluster."


■ Go out late this evening to catch the waning gibbous Moon near 3rd-magnitude Gamma Virginis (Porrima), as shown below. Gamma Vir is a fine telescopic double star at high power. The two equal components are separated by 3 arcseconds and are aligned north-south.

Late tomorrow evening the Moon stands with lower Spica.

Moon passing Gamma Virginis and Spica, Feb. 8-10, 2023
On two nights, the Moon pairs with Gamma Virginis and Spica, the two leading stars of Virgo. (The Moon is shown three times its actual apparent size.)


■ Sirius the Dog Star blazes in the southeast after dinnertime, below Orion. It's the brightest star of Canis Major. In a dark sky with lots of stars visible, the constellation's points can be connected to form a convincing Big Dog profile. He's currently standing on his hind legs. Sirius is on his chest, to the right or lower right of his faint triangular head.

But through the light pollution under which most of us live, only his five brightest stars are easily visible. These form the Meat Cleaver. Sirius is the cleaver's top back corner, its blade faces right, and its short handle is down below pointing lower left.

■ The waning gibbous Moon rises around 11 p.m., depending on your location, with 1st-magnitude Spica about 3° to its lower right as shown above.

Mars, Aldebaran and the Pleiades, Feb. 10, 2023
Mars is moving eastward (left) against the stars; the angle from the Pleiades to Mars to Aldebaran has become acute.


■ Right after nightfall this week, the W of Cassiopeia shines high in the northwest standing almost on end.

The brightest star between Cassiopeia and the zenith right after dark, seen from the world's mid-northern latitudes, is Alpha Persei (Mirfak), magnitude 1.8. It lies on the lower-right edge of the Alpha Persei Cluster: a large, elongated, very loose scatter of fainter stars about the size of your thumbtip at arm's length. At least a dozen are 6th magnitude or brighter. They show best in binoculars.

Alpha Per, a white supergiant, is a true member of the group and its brightest light. It and the rest are about 560 light-years away.


■ High in the northern sky these evenings, in the seemingly empty wastes between Capella overhead and Polaris due north, sprawls big, dim Camelopardalis, the Giraffe — perhaps the biggest often-visible constellation you don't know. Unless you have a really dark sky, you'll need binoculars to work out its loose, faint, nondescript pattern using the constellation chart in the center of Sky & Telescope — a challenge project that will build your skills for correctly relating what you see in binoculars to what you see, much smaller, on a sky map.

If you're new at this, start with brighter, easier constellations and save the shy Giraffe until you get good at it.



This Week's Planet Roundup

Mercury starts coming down from its good dawn apparition. Look for it low in the southeast starting about 40 minutes before your local sunrise time. It's the brightest thing there, still about magnitude –0.1 all week. Binoculars may help.

Don't confuse Mercury with lesser Altair about three fists at arm's length to its upper left, or Antares four or five fists to Mercury's upper right.

Venus, the brightest planet at magnitude –3.9, shines low in the west-southwest in evening twilight. It's lower right of Jupiter, the second-brightest planet. Venus sets about a half hour after twilight's end. Telescopically it's still just a shimmering little ball, 11 arcseconds in diameter and noticeably gibbous (90% sunlit).

Mars, in Taurus, shines very high toward the south, almost overhead, in early to mid-evening. Mars continues to fade, from magnitude –0.2 to 0.0 this week, and is 10 arcseconds wide. It too is gibbous (91% sunlit).

Spot Aldebaran, mag +0.8, below Mars (by 8°) in early evening, and lower left of Mars later in the evening.

Receding Mars as imaged on February 2nd by Christopher Go in the Philippines. South here is up. Upper left of center, the most prominent diagonal dark marking is Mare Sirenum. The North Polar Cap has become obvious. A little above it the small gray patch is Elysium with thin clouds across and around it. The dark arc just inside the bright limb is partly a processing artifact, but the dark margin of the North Polar Cap at bottom is a known thing.
Mars imaged on Jan. 16, 2023, with Sinus Meridiani
Mars as imaged on January 16th by Christopher Go. South here is up. Sinus Meridiani with its two downward prongs is at center. Sinus Sabaeus is the dark band running left from there. Through northern clouds, the whiter north polar cap is visible. Syrtis Major is departing on the left limb.  Hellas Basin, above Syrtis Major, has turned brighter with cloud or frost.
Mars on Dec. 22, 2022, with Mare Cimmerium and Mare Tyrrhenum
The nearly opposite side of Mars, imaged by Go on December 22nd. Syrtis Major is the dark arc near the lower right limb. Just above center, the two large, parallel, mottled diagonal bands are Mare Cimmerium (left) and Mare Tyrrhenum. The pointy lower-right end of Mare Cimmerium is Tritonis Sinus. Two small prongs point down from Cimmerium; the darker one is Gomer Sinus.

Jupiter, magnitude –2.2 at the Pisces-Cetus border, shines in the southwest in twilight upper left of Venus, then sinks toward the west and sets around 9 or 10 p.m. Telescopically, Jupiter has shrunk to only 35 arcseconds wide.

Jupiter imaged on January 15, 2023
Jupiter on January 15th, imaged by Christopher Go. South is up, east is right. Notice that Jupiter's eastern limb is shadier than the western limb, Jupiter being near eastern quadrature with the Sun. The black dot is the shadow of Io. The Great Red Spot is rotating onto the disk from the east.

Saturn has disappeared into the bright glow of sunset.

Uranus, magnitude 5.8 in southern Aries, is high in the southwest in early evening. It displays a tiny, very slightly blue-greenish gray disk 3.6 arcseconds wide. It a telescope at high power it's obviously non-stellar. See the Uranus finder charts in the November Sky & Telescope, page 49.

Neptune, magnitude 8.0 at the Aquarius-Pisces border, is getting low in the southwest between Jupiter and Venus. You could still try for it immediately after dark, using the Neptune finder charts in last September's Sky & Telescope, page 49.

All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time (EST) is Universal Time minus 5 hours. Universal Time is also called UT, UTC, GMT or Z time.

Want more sky scenes? Use our Interactive Sky Chart to get sky views in any direction, for any date, any time, and any location on Earth!

Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For a more detailed constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a much more detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows all stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading outdoors by red flashlight. Sample charts. More about the current editions.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And be sure to read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet as to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner.

Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically. And as Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."

Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the heavens above. It's free.

"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
            — Carl Sagan, 1996

"Facts are stubborn things."
             John Adams, 1770


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February 5, 2023 at 4:16 am

■ The waning gibbous Moon rises around 11 p.m., depending on your location, with 1st-magnitude Spica about 3° to its lower right ..."

The Sun is in conjuction with Spica every year around October 15th, so when eclipses occur in April and October, one of the nodes is passing by Spica and a series of occultations of Spica occurs.

In fact, the Annular Solar Eclipse this year occurs with the Sun and Moon near Spica, with the Moon near its descending node..Something similar happened during the August 2017 total eclipse when Regulus was in conjuction with both the Moon and the Sun, it and was very close to both of them. Of course with an annular eclipse the sun is not completely blocked so the sky is too bright to see Spica (but bright Venus may be visible a little further away).

Spica lies below (South) of the Ecliptic, and the Moon is a few days away from the descending node, so the Moon will pass North of the Sun (as seen from the center of the Earth) and a little further North from Spica. As the descending node retrogrades westward, the Moon will pass further south and eventually start occulting Spica starting in 2024.
But you can watch each month as the Moon passes Spica, and see it pass closer and closer each month.

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February 5, 2023 at 4:19 am

While waiting for the Spica occultation series to begin in 2024, you can watch the Moon pass closer and closer to Antares each month. An lunar occultation series for Antares begins six months from now in August, so you/we can watch the moon pass closer to that star between now and August.

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mary beth

February 5, 2023 at 11:00 am

Thank you for this interesting information. I’m a big fan of both stars and have a great almost unobstructed view from my yard here in Houston all summer and early autumn long.

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February 6, 2023 at 10:20 pm

Did you see last week's occultation of Mars?
My neighbor has family living near Houston, and for them, the December Moon/Mars conjunction was just a "near-miss" and not an occultation.

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mary beth

February 9, 2023 at 4:00 pm

Unfortunately did not see. Was able to enjoy the Venus/Saturn conjunction a few weeks ago though. And yes, the December was a near-miss at out latitude, but still was fun to watch!

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February 6, 2023 at 10:17 pm

... speaking of Regulus and the Moon, tonight (Monday Feb 6th) the passes by Regulus.
Back in Summer 2017 the Moon's ascending node was near Regulus and there were a series of occultations (including a daytime occultation during the total solar eclipse but only "visible" a few hundred miles south in Mexico).

Now the ascending node has retrograde about 120 degrees to the West (it was 90 degrees from Regulus a year ago in Spring 2022). The Moon is still near its maximum 5 degrees north of Regulus, so if you look at them tonight you can get an idea of how much the Moon's orbit is tilted from the Ecliptic.

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February 6, 2023 at 10:48 pm

"Comet ZTF is only observable through moonlight for part of this week, but have a look with binoculars or a telescope anyway!"

I did get out and view the comet tonight 🙂

Observed 2100-2200 EST. Waning gibbous Moon in Leo. I viewed C/2022 E3 (ZTF) using 10x50 binoculars and 90-mm refractor telescope at 111x using TeleVue 9-mm Nagler. The comet is magnitude 5.7 according to and easy to see just a bit more than 11 arcminute from the orange color K5 II+B7V double star, eclipsing binary Saclateni or Haedus I in Auriga. The Telrad made for quick locating in Auriga tonight. The comet using 10x50 binoculars near the distinct orange color of Haedus I, no problem viewing. The orange color combination with comet in the FOV, made for a good view and at 111x, distinct coma, fuzzy, with hint of tail with Haedus I orange color. The sky clear, temperature 3C, winds 320/6 knots.

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February 7, 2023 at 7:21 pm

A great report here! 🙂

I tried to see the green comet and totally failed. I needed more planning and equipment than I expected.

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