Sky This Week is brought to you in part by Celestron.
Friday, March 14
The Moon reaches Full phase early this morning at 2:55 A.M. EDT, with a total lunar eclipse underway. Everyone across the U.S. can watch the event, and no special equipment is needed — just your eyes!
Totality begins about half an hour earlier, at 2:26 A.M. EDT. The moment of greatest eclipse is at 2:59 A.M. EDT, which is the midpoint of the “total” part of the eclipse. Totality ends at 3:31 A.M. EDT, after which early risers can watch the Moon progressively slip out of Earth’s shadow, with the partial phase ending at 4:47 A.M. EDT and the eclipse fully ending at 6 A.M. EDT..
In the evening sky, Mercury reaches its stationary point in Pisces at 5 P.M. EDT. It’s visible for a little over an hour after sunset, standing just to the upper left of Venus, a blazing magnitude –4.3 beacon in the twilight sky. Mercury is much fainter at magnitude 0.8, so you’ll need to let darkness start to fall before spotting it just under 6° from Venus. Binoculars or a telescope will greatly aid your search.
About half an hour after sunset, the pair is 8° high in the west. Compare them through a telescope — Venus is just 3 percent lit but a whopping 58” wide, while Mercury is a slightly larger 18-percent-lit crescent but only 9” in angular size.
Sunrise: 7:13 A.M.
Sunset: 7:06 P.M.
Moonrise: 7:44 P.M.
Moonset: 7:23 A.M.
Moon Phase: Full
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
Saturday, March 15
Mars skims a mere 8’ northeast of 57 Geminorum this evening, and observers can take in the view through binoculars or a telescope.
Mars is now magnitude 0, standing more than 70° high in the south an hour after sunset. It remains visible all night and into the early morning, setting around 4:30 A.M. local daylight time. The Red Planet now hangs below Castor and Pollux, the two 1st-magnitude stars marking the heads of Gemini the Twins, high above Canis Major and Orion and to the left of Taurus the Bull (which currently houses Jupiter) in the early-evening sky.
Once you’ve spotted ruby-red Mars, use binoculars or a telescope to check out 5th-magnitude 57 Gem nearby. Mars itself is not quite full, but roughly 90 percent lit — can you tell? The martian disk currently spans just 9”, the same angular size as Mercury. Although Mars can sometimes appear much larger, it is now more than 90 million miles (145 million kilometers) from Earth. Its small size means surface features are difficult to see except under the best conditions with large scopes and video-capture capabilities, but anyone can note its orange-red color, which comes from sunlight lighting up oxidized (rusted) iron on its surface.
Sunrise: 7:11 A.M.
Sunset: 7:07 P.M.
Moonrise: 8:44 P.M.
Moonset: 7:42 A.M.
Moon Phase: Waning gibbous (98%)
Sunday, March 16
The Moon passes 0.4° south of Spica at 4 P.M. EDT. A few hours after moonrise — say, local midnight — you can spot the pair some 25° high in the southeast. The wanng gibbous Moon is quite bright, but magnitude 1 Spica, to its upper right, should still shine through.
Spica is Virgo’s alpha star. Its position is very close to the ecliptic, meaning it is often occulted by the Moon — and, indeed, some observers in western Africa and parts of Madagascar will see the Moon pass in front of, rather than simply close to, Spica today.
Only some 250 light-years distant, Spica is a blue-white star nearly 2,000 times brighter than our Sun in visible light. It is actually a system of multiple stars that orbit very close together, the two brightest with a period of just over 4 days. They are so close that they cannot be split with a telescope.
Some 14.5° to Spica’s upper right around midnight is a fainter star: magnitude 2.7 Porrima. This is also a multiple star, but one that can be split by small scopes. Its components are roughly 3” apart and shine at similar magnitudes of 3.6 and 3.7.
Sunrise: 7:09 A.M.
Sunset: 7:08 P.M.
Moonrise: 9:45 P.M.
Moonset: 8:01 A.M.
Moon Phase: Waning gibbous (95%)
Monday, March 17
The Moon reaches apogee, the farthest point from Earth in its orbit, at 12:37 P.M. EDT. At that time, our satellite will sit 252,124 miles (405,754 kilometers) away.
With the Moon rising late in the evening, there’s time before moonrise to catch an asteroid in action. Magnitude 9.5 29 Amphitrite is moving through Leo, 50° high in the southeast by 9:30 P.M. local daylight time, with a little over an hour to go before moonrise. First locate 3rd-magnitude Epsilon (ε) Leonis, the star that tips the curved blade of the Sickle asterism outlining the Lion’s head. From there, move 3.4° west to land on 4th-magnitude Lambda (λ) Leo. Finally, drop just over 4° southwest to locate Amphitrite, using the finder chart above to guide you.
Once you’re done enjoying the sight of the main-belt world through your scope, skim back over toward Epsilon and then some 9° southeast to enjoy 2nd-magnitude Gamma (γ) Leo, a lovely gold and yellow double star pair separated by some 5”.
Sunrise: 7:08 A.M.
Sunset: 7:09 P.M.
Moonrise: 10:46 P.M.
Moonset: 8:22 A.M.
Moon Phase: Waning gibbous (90%)
Tuesday, March 18
Let’s visit Jupiter in Taurus tonight to check out one of several double transits of Ganymede and Europa this month.
An hour after sunset, Jupiter is nearly 60° high in the west, starting to slowly set amid the stars of Taurus. At magnitude –2.1, it’s the brightest point of light in the Bull by far, located to the upper right of Aldebaran as the constellation sets.
Telescopic observers on the East Coast and in the eastern Midwest will be able to catch Jupiter before either transit has started, as Ganymede lies close to the planet’s southeastern limb with Europa a little farther away. Just west of the planet is Io, while Callisto lies far to the west.
Ganymede’s transit begins around 9:30 P.M. EDT; the large moon travels in front of the disk alone for almost an hour before Europa begins to transit at 10:18 P.M. EDT. Keep your eyes west of Jupiter as you track the two moons across — Io disappears behind the planet a few minutes after 10:50 P.M. EDT.
At that time, Ganymede is roughly halfway through its transit. It finally reaches Jupiter’s southwestern limb around midnight EDT. Less than an hour later, around 12:50 A.M. EDT (now the 19th in the Eastern time zone), Europa’s shadow appears on the cloud tops at Jupiter’s southeastern limb. Some five minutes later, Europa’s transit ends.
Ganymede’s shadow won’t appear until roughly 12:50 A.M. MDT, with Jupiter some 6° high in the Mountain time zone. Europa’s shadow transit ends around 12:30 A.M. PDT, with Jupiter only visible for the West Coast. The planet will set before the huge blot of Ganymede’s shadow can fully cross it.
Sunrise: 7:06 A.M.
Sunset: 7:11 P.M.
Moonrise: 11:49 P.M.
Moonset: 8:47 A.M.
Moon Phase: Waning gibbous (83%)
Wednesday, March 19
Neptune is in conjunction with the Sun at 7 P.M. EDT, rendering the ice giant invisible from our point of view. It will reappear in just a few weeks, gracing the morning sky by mid-April.
Following last night’s transits of Ganymede and Europa, Io and its shadow are now transiting Jupiter. Through your telescope, you’ll see that Io is already in front of the disk and transiting as the sky grows dark for U.S. observers farthest east. Again, Jupiter is the brightest light in Taurus, high in the western sky as daylight fades.
As Io crosses, the other three Galilean moons already lie far west of the planet. Europa is closest, with Ganymede slightly farther and Callisto still the most distant from Jupiter. Io is joined by its shadow, roughly over the gas giant’s equator, shortly before 9:30 P.M. EDT. The moon finishes its transit at 10:20 P.M. EDT, with its shadow now centrally located on the disk. This time, the entire shadow transit is visible to all in the U.S., ending shortly before 11:40 P.M. EDT.
Sunrise: 7:05 A.M.
Sunset: 7:12 P.M.
Moonrise: —
Moonset: 9:17 A.M.
Moon Phase: Waning gibbous (76%)
Thursday, March 20
The vernal equinox occurs at 5:01 A.M. EDT, ringing in the start of astronomical spring in the Northern Hemisphere. Today, the Sun crosses from south to north of the celestial equator and Earth sees roughly equal amounts of daylight and darkness.
If you’re up early this morning, you can catch the Moon standing close to the red giant Antares, which marks the heart of Scorpius the Scorpion. Around 5 A.M. local daylight time, the entire constellation is above the southern horizon from mid-latitudes. Antares, which glows at magnitude 1.1, lies just to the upper left of the Moon. Even with our satellite’s bright light nearby, you’ll likely still be able to tell that this star has an orangey hue. That’s because it is an aging red giant that has swelled in size but cooled off as it did so, causing its light to redden.
Antares is a huge star that, if dropped into the center of our solar system, would stretch roughly out to rest in the middle of the main belt of asteroids between Mars and Jupiter. Even at a distance of 550 light-years, astronomers have been able to image the star’s disk and observe darker, cooler starspots on its surface.
The Moon will pass 0.5° due south of Antares at 1 P.M. EDT this afternoon, when both are below the horizon in the daytime sky.
Sunrise: 7:03 A.M.
Sunset: 7:13 P.M.
Moonrise: 12:52 A.M.
Moonset: 9:52 A.M.
Moon Phase: Waning gibbous (67%)
Friday, March 21
Let’s cap off the week with some deep-sky observing back in Leo, where a famous trio of galaxies should be visible during the dark hours of the evening, as the Moon won’t rise until well after midnight.
The so-called Leo Trio or Leo Triplet is near the hindquarters of the Lion, climbing in the east as darkness falls. The group contains the galaxies M65, M66, and NGC 3628, and is relatively easy to find — M65, our starting point, lies about halfway between the stars Theta (θ) and Iota (ι) Leo. Glowing at magnitude 9.3, M65 is the southwesternmost galaxy in the triplet. It is a spiral galaxy about four times as long as it is wide, and shows up best in medium or large scopes.
Just 0.3° southeast of M65 is M66, which is slightly brighter at magnitude 8.9. This time, the spiral appears only twice as long as it is wide, and its brighter nucleus is more obvious. Larger amateur scopes might pick up a darker dust lane east of the nucleus.
The third galaxy in the Leo Triplet is the faintest: magnitude 9.5 NGC 3628, three to four times as long as it is wide (depending on the size of your scope and how much of the galaxy’s light it will pick up). Astronomy associate editor Michael Bakich likens this galaxy to the Cigar Galaxy (M82) — like the Cigar, this starburst galaxy is frenetically forming stars after a close encounter with its neighbor (in this case, M66). Take care when observing this galaxy, as bumping up the magnification will cause it to better blend in with the background sky, making it harder, not easier, to see.
Sunrise: 7:01 A.M.
Sunset: 7:14 P.M.
Moonrise: 1:54 A.M.
Moonset: 10:36 A.M.
Moon Phase: Waning gibbous (58%)
