Category: Stargazing

Students gathered under the stars in Hawaii recently to explore the awesome nature of the night sky together.

What is it?

From Oct. 19 to Oct. 22, more than 1,400 students on the Big Island of Hawaii gathered for the Journey Through the Universe event to explore astronomy together.

The Journey Through the Universe program is currently in its 23rd year. It was originally developed by the National Center for Earth and Space Science Education (NCESSE) and later introduced in Hawaii by the international Gemini Observatory, a program within the U.S. National Science Foundation's NOIRLab (National Optical-Infrared Astronomy Research Laboratory) that works with the Department of Education Hilo-Waiākea.

The program aims to introduce students in the Hilo-Waiākea public school system to astronomy as well as the incredible science that happens across Hawaii. The students who participate range from preschoolers to seniors in high school, so the program introduces some students to astronomy and helps others explore possible careers in STEM fields.

This year, the program brought in 19 volunteer educators from scientific institutions like Maunakea Observatories and supported hands-on activities and lessons that went from the classroom to under the Milky Way.

Why is it incredible?

This image shows a growing love for astronomy in progress. From the red glow of a skywatching night (red light doesn't interfere with our ability to see at night like white light does) to the scattered telescopes and students standing under the stars, this scene paints a larger picture.

This is just one program, but in bringing together volunteers, educators, scientists and students, the program has created an incredible and enduring learning experience.

Whether or not students walk away wanting to pursue a career in STEM, this incredible immersion in astronomy can help to foster a lifelong appreciation for science and nature. It's always a great idea to gather under the stars and explore together.

Betelguese, one of the brightest stars in the night sky, has been putting on quite a show lately — but not in the way you might expect.

The famous red supergiant in the constellation Orion has been growing noticeably fainter in recent months.

Of the 21 brightest stars in the night sky, Betelgeuse is perhaps the most enigmatic. Its changing brightness poses a puzzle: how do the star's pulsations, dust eruptions, and a possible companion contribute to its fading?

A giant star with a puzzling name

Even the translation of Betelgeuse's name is contentious. For a long time, it was thought to be a corruption of three Arabic words, usually translated as "The Armpit of the Giant." However, other experts in star nomenclature now dispute that interpretation, proposing instead "The Hand of al-Jauzā," with al-Jauzā referring to Orion.

Although classified as a red supergiant, Betelgeuse usually appears more orange than red— golden orange or deep topaz. It is one of the most famous stars in its class. Henry M. Neely (1877-1963), for many years a popular lecturer at New York's Hayden Planetarium, described its restless behavior in his book A Primer for Stargazers:

"(Betelgeuse) expands and contracts spasmodically, like an old man with his strength almost entirely spent, panting in the asthmatic decrepitude of old age."

The rhythms of a changing star

Betelgeuse naturally expands and contracts like a beating heart. As an aging red supergiant, it has a regular pulsation cycle of roughly 430 days: when it expands, its outer layers cool and it dims; when it contracts, they heat up and it brightens. Among first-magnitude stars — the brightest category of stars in the night sky — it is the only marked variable. Its scale is equally remarkable: located 650 light-years away, Betelgeuse is among the largest and most luminous stars of its class, with a luminosity of about 14,000 suns at maximum and 7,600 suns at minimum. Only a few such objects have been identified in our galaxy.

British astronomer Sir John Herschel (1792-1871) first noticed Betelgeuse's variability beginning in 1836. Astronomers describe apparent brightness using magnitude: lower numbers mean brighter stars. In April 2023, Betelgeuse reached magnitude 0.0 — as bright as Vega, the fifth brightest star. At minimum brightness, such as in 1927 and 1941, its magnitude may fall to +1.2, making it appear about three times fainter.

Three threads run through this mystery: Betelgeuse's roughly 430-day pulsation, its much longer recurring dimming cycle, and the exceptional Great Dimming of 2019—2020. Keeping them, separate helps explain why one cause need not account for every change in brightness.

A longer cycle and a possible companion

Alongside its roughly 430-day pulsation, Betelgeuse shows a mysterious 2,100-day (5.75-year) dimming cycle. Known as a "Long Secondary Period," this longer cycle puzzled astronomers for a century. Some suggested that one or more stars might orbit Betelgeuse; others found no evidence for such companions or actively refuted their existence.

At long last, in January 2026, researchers using the European Southern Observatory's Very Large Telescope (ESO's VLT) located in on Cerro Paranal in the Atacama Desert of northern Chile and NASA's Hubble Space Telescope, published the clearest images and direct evidence of a faint companion star orbiting the red supergiant. Formally named Alpha Ori B, Jared Goldberg, an astrophysicist researching the phenomenon, nicknamed the companion star "Betelbuddy," though in deference to the new definition of Betelgeuse's name meaning "the hand of al-Jawzā," the name Siwarha was ultimately chosen for the probable companion star, which means her bracelet in Arabic.

In this explanation, Siwarha orbits deep within Betelgeuse's outer chromosphere, a layer of its atmosphere, circling about every six years. As it moves through gas and dust ejected by the supergiant, its gravity creates a dense wake of gas, with ripples and shockwaves that disrupt stellar winds and mass loss. When the concentrated dust trail passes between Earth and Betelgeuse, it can make the main star appear decidedly dimmer.

Compare Betelgeuse with Aldebaran

Betelgeuse recently experienced another sharp drop in brightness. Since this past August, it has faded from magnitude +0.5 to +0.95 and now appears just a trifle dimmer than the similarly hued orange star Aldebaran in Taurus the Bull. This decline may be another example of the dimming described above, although the brightness change alone does not establish its cause.

Aldebaran can be used as a comparison to Betelgeuse, since they both happen to be in the general vicinity of each other. If you want to make such a determination yourself, keep in mind that Aldebaran currently rises in the east-northeast before 7 p.m. local standard time, followed about 90 minutes later by Betelgeuse, which will emerge from beyond the eastern horizon. By 11:30 p.m., both stars will be well placed for viewing in the east-southeast part of the sky.

Betelgeuse marks Orion's right shoulder. To locate Aldebaran, look for the three bright, evenly spaced stars that form Orion's belt. Draw an imaginary line through the three belt stars and extend it upwards and to the right. Follow that line for about two fists' width at arm's length (roughly 22 degrees) until you hit a sideways, V-shaped cluster of stars known as the Hyades, which forms the face of Taurus. Aldebaran sits right at one end of that V-shape, glowing with a distinct orange-red color as the "angry eye" of the bull charging toward Orion.

View them late tonight; which star appears brighter?

The Great Dimming of 2019—2020

The changes visible now invite comparison with a far more dramatic episode: The Great Dimming Event of 2019—2020.

Between October 2019 and February 2020, Betelgeuse experienced an unprecedented, dramatic plunge in brightness — losing over two-thirds of its luster, falling from magnitude +0.5 to +1.7; the rank of a second magnitude star. It then returned to a more normal brightness, reaching an unusually bright peak of 0.0 by the spring of 2023. While the sudden dimming caused internet and media speculation that Betelgeuse was about to die as a spectacular supernova, infrared structural and chemical models showed no significant change in the star's luminosity; Betelgeuse was still firmly in its helium-burning phase and is expected to live for another 100,000 to perhaps many hundreds of thousands of years before it explodes.

So, what caused The Great Dimming? The mystery was ultimately solved by compiling data from the Hubble Space Telescope and ground observatories.

Apparently, Betelgeuse "sneezed."

A massive bubble of superhot plasma rose from a giant convection cell inside the star and blasted into space. As this ejected gas moved millions of miles away from the star, it cooled rapidly and condensed into solid silicon monoxide dust. This giant stardust cloud acted like a literal screen, blocking a substantial portion of the star's light from our viewpoint. This event was exacerbated because the massive eruption perfectly aligned with the lowest point of the star's 430-day pulsation cycle as well as the orbital interference of the companion star Siwarha.

From the standpoint of producing the absolute maximum possible dimming of Betelgeuse, this cosmic trifecta was the perfect storm!

Untangling the mystery

Betelgeuse has long been known as a variable star, and recent breakthroughs are helping astronomers untangle its erratic behavior. Internal pulsations and massive dust eruptions contribute to its changing brightness, while gravitational interactions with the newly reported, probable companion explain the longer dimming cycle. Together, these mechanisms paint a richer picture of why Orion's giant star fades and brightens.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.

This is a great month for planet watching, either in the evenings or mornings. During convenient evening hours, the planet of choice is Saturn, visible well up in the southern sky during mid-to-late evening hours. Telescopically, the southern side of its famous ring system is currently tilted about 6½ degrees to our line of sight.

Around the middle of the night, Mars and Jupiter come into view above the east-northeast horizon and just before the break of dawn are in excellent position, soaring high in the southern sky in the vicinity of the Sickle of Leo the Lion. Watch how Mars approaches Jupiter early in the month, passes it on Nov. 16, then spends the rest of the month sailing away to the east.

Meanwhile, in the predawn morning sky, Venus literally vaults into prominence as the month progresses. And from midmonth on through the end of November, Mercury asserts itself, appearing as a very bright "star" to the far lower left of Venus.

In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm's length measures roughly 10 degrees. Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them

Reminder: On Nov. 1 — where applicable — change clocks back one hour from Daylight Saving Time. On this date, the clock hour from 1 to 2:00 a.m. is repeated, thus making this day the longest of the year: 25 hours long. The mnemonic is: "Spring Ahead, Fall Back."

Mercury

Mercury, hidden during inferior conjunction with the sun on Nov. 4, will emerge in the eastern morning sky after the second week of the month to undergo an excellent morning apparition for the Northern Hemisphere. This rocky little world arrives at its greatest western elongation (20 degrees) from the sun on Nov. 20; its most favorable morning apparition of the year for mid-northern observers. From Nov. 16 to Nov. 26 speedy Mercury will rise in the east-southeast before the beginning of astronomical twilight, more than 95 minutes before sunrise.

Venus

Venus is a good reason to be up at the crack of dawn in November; it's a silvery lamp that rises above the east-southeast horizon. Venus was at inferior conjunction on Oct. 24. But the steep angle of the ecliptic at dawn in late autumn helps Venus vault noticeably higher with each passing day for observers at mid-northern latitudes. On Nov. 1, it rises 55 minutes before the sun. But just several days later on Nov. 5, viewers around 40 degrees north latitude can see Venus come up one hour and 25 minutes before the sun and shine 15 degrees above the horizon at sunrise. As November ends, Venus rises nearly 3½ hours before the sun and hangs nearly 35 degrees up at sunrise.

All month Venus brightens impressively and on the penultimate day of the month it will reach the pinnacle of its magnificent brightness, shining at magnitude -4.9, rising almost 3½ hours before the sun. If there's snow on the ground, check for shadows made by Venus's light. Through a telescope, the phase of the planet looks most remarkable early in the month. That's when you may be able to glimpse Venus when it's only a few percent illuminated, a hairline crescent close to an arcminute long; about 1/30 the apparent diameter of the moon. Venus is not alone in the dawn sky.

Its leap takes it up into the proximity of the bluish 1st-magnitude star Spica in Virgo on the morning of Nov. 3. The star will be sitting 2.4 degrees to the upper right of Venus. During this month, Venus seems to perform a dos-à-dos with Spica and at first seems destined to soar up and catch it. Instead, the closest it gets to this star is 1.8 degrees to its upper left early on the morning of Nov. 19.

On the morning of Nov. 7, a striking array of a waning crescent moon, brilliant Venus and Spica awaits early risers low in the east-southeast sky about an hour before sunrise. The trio will be bunched together inside of a circle measuring only about 2½ degrees in diameter.

Mars

Mars, shining at magnitude +0.9, is in Leo in the morning sky and is easily found on the morning of Nov. 2, using the moon as a guide. That day it sits a couple of degrees to the left of the moon. In addition, on that date, Mars is positioned 5 degrees to the upper right of much brighter Jupiter.

Mars has been hiding in the glare of the sun, or in the dead of the early morning hours, for the last year and a quarter. Now it finally rises in the east before midnight. Each night, watch the orange-yellow planet move a little closer to Jupiter. They'll be in conjunction on Nov. 16 (See Jupiter below).

On the morning of Nov. 26, Mars, having brightened to magnitude +0.6, passes 1.7 degrees to the upper left of the first magnitude star Regulus in Leo. The color contrast between the orange-yellow planet and blue-white star is striking, especially in binoculars.

Jupiter

Jupiter is high enough for a steady telescopic view by 3 a.m. But its dusky cloud belts and Red Spot can be seen more clearly when the planet is highest in the southeast soon after dawn breaks.

On Nov. 3, shortly after 1 a.m. local time, look low toward the east-northeast horizon to watch the moon slowly ascend the sky. The 1st magnitude star Regulus will be evident sitting a degree to the moon's left. And sitting about 5 degrees above the moon will be Jupiter, appearing as a brilliant "star" shining with a steady, silvery light.

Mars passes 1.2 degrees to the upper left of Jupiter on Nov. 16; the giant planet outshining the red planet 13-fold. Late on Nov. 29 and into the early hours of Nov. 30, look low toward the east-northeast horizon for a gathering of the waning gibbous moon, with Jupiter, Regulus and Mars. These four celestial bodies cover an expanse of roughly 7 degrees going from right to left. Best views will come around the time of the break of dawn when they'll appear to soar high in the southern sky.

Saturn

Saturn is situated in the northeast corner of the non-zodiacal constellation of Cetus the Whale (or Sea Monster). It crosses the southern meridian around 9:45 p.m. at the beginning of November and about two hours earlier at the month's end. All evening, it is excellently placed for telescopic viewing of its glorious ball and rings. At magnitude +0.6, Saturn is easily the brightest point of light in its section of the heavens. It can also be told from the stars by its steady, yellowish light.

On the evening of Nov. 18, take note of Saturn mimicking a bright "star" shining about 6 degrees below the waxing gibbous moon.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.

The moon dives towards the glowing heart of the constellation Leo for a spectacular rendezvous with Mars and Jupiter overnight on Nov. 1-2, as the glittering stars of the Beehive Cluster shine nearby. Here's what you need to know.

Look to the eastern horizon an hour after midnight to see the 45%-lit waning moon shining less than 5 degrees from the red light of Mars — roughly the width of your three middle fingers held at arm's length to the night sky.

Jupiter's bright light will gleam just below the red planet, with the bright star Regulus lining up beyond to form a dazzling procession leading back to the horizon. The stars of the Beehive Cluster (M44) can be found twinkling 10 degrees from the unlit side of the lunar disk around this time, in the middle of the constellation Cancer.

Stargazers in Australia, Indonesia and a host of other island nations and territories will see the moon pass directly in front of Jupiter, hiding its light in an event known as an occultation starting at 3:45 p.m. EST (2045 GMT) on Nov. 2 , according to In-The-Sky.org. However, the exact visibility and timings depend on location.

The cosmic pile-up serves as a spectacular reminder of the scale and diversity of targets on display in the night sky. After all, the moon appears largest from our Earthly perspective, but in reality it's less than half the diameter of Mars.

Jupiter, meanwhile, is over 20 times wider than the red planet, while mighty Regulus is up to four times larger than the sun, andcould easily fit all the planets of the solar system in its vast expanse.

By moonrise on the night of Nov. 3, the lunar crescent will have leapt past Jupiter and Mars, to appear just 1 degree from the blue-white light of Regulus for viewers in the U.S. Meanwhile, viewers in several South American countries including Brazil, Peru, Argentina and Bolivia will see the moon occult Regulus beginning at 6:59 EST (1024 GMT) on Nov. 3. The exact timings for a selection of South American countries can be found below, courtesy of In-The-Sky.org.

Want to get a closer look at the moon and planets of the solar system? Then be sure to check out our picks of the best telescopes and binoculars for exploring the night sky, including the Celestron NexStar 8SE, which we rank as the best motorized telescope out there.

Editor's Note: If you would like to share your astrophotography with Space.com's readers, then please send your photo(s), comments, and your name and location to spacephotos@space.com.

There could be more than just ghosts and ghouls lurking in the skies this Halloween! From Saturn's spectacular rings to shooting stars and even a space station flyover, the night sky has a few treats of its own in store for U.S. skywatchers on Oct. 31.

Based on the latest national forecast, skies will be mainly clear on Saturday evening over most of New York State, northeast Pennsylvania, northern New Jersey and New England as well as a swath of the southern and central Great Plains, central Rockies, a portion of the Pacific Northwest and central and south Florida, as costumed kids arrive at the door looking for candy or some other Halloween treat.

Temperatures will be mostly in the chilly 40s across the Northeast US, upper 50s and 60s for the nation's midsection, warm 70s to near 80 for the southern US, including Florida and the Gulf Coast, and 40s for much of the western US. Unfortunately, a storm moving across the nation's heartland may spell rainy skies for parts of Iowa and Nebraska, south to the Gulf Coast.

For those blessed with a generally fair evening, there will be views of mid-autumn stars and constellations plus a bright planet shining prominently in the early evening sky. If you plan to accompany children around your neighborhood, you might want to enlighten them by pointing out some of those objects that will be visible in the sky. Better yet, if you have a telescope, give your visitors a treat of a different kind: Give them a close-up view of some of those celestial sights.

At the top of the viewing list: The lord of the rings

At around 7 p.m. local time, tell your young audience to make a clenched fist with their hands and then hold them out at arm's length. Now, tell them to go "two fists" up from the east-southeast horizon and they will see a bright star, shining with a yellow-white hue. Now, direct your telescope toward that "star" and when you gaze through the eyepiece, you will not be looking at a star at all . . . but a planet!

Saturn.

This sixth planet out from the sun, just might be the most beautiful of all. Its rings are still readily evident, although currently they appear somewhat edge-on with the south face tilted only about 6 and a half degrees to our line of sight. A telescope magnifying 30-power will bring them out; they appear to bisect the ball of the planet. While this is far from their appearance compared to other years, the view should still look impressive to those who have never seen the ringed planet for themselves.

And watch out for fireballs!

Because they are active over Halloween, the Taurid meteor shower is sometimes called the "Halloween Fireballs." The bits of debris that make up the Taurids are a little larger than average, so they can result in brighter meteors and even fireballs, or exploding meteors (called bolides), that streak across the sky and leave incandescent trains in their wake. While they are most active during the second week of November, a few forerunners can show up on Halloween night, darting from out of the east-northeast part of the sky. So, if you or your young visitors see something resembling a flare from a Roman candle sweeping majestically across the evening sky, it may very well be a Taurid meteor.

And for those in the Northeast U.S., a space station!

Not the International Space Station, but the Tianhe-1 core module, the first module to launch of the Tiangong space station. It was launched into orbit on 29 April 2021, as the first launch of the final phase of the Tiangong program, part of the China Manned Space Program (Project 921). On Halloween evening, Tianhe-1 will be following a track from Chicago to New York at an altitude of 240 miles (385 km) and should be readily visible to the naked eye across the Northeast US within a few minutes of 7 p.m. EDT, wherever skies are reasonably clear.

The Tiangong Space Station should appear to resemble a very bright star moving across the sky on a general west-to-east course. For places near and along the flight path, the Space Station will appear to pass almost directly overhead. For those situated south of the track, Tiangong will reach its highest point above the northern horizon; those situated north of the track will see the station peak high in the south.

If you see it, tell your young viewers that three astronauts are currently living and working aboard the Tiangong Space Station, of which the Tianhe core module serves as the main living quarters. If you would like specific details on when and where to see the Space Station from your hometown, check out Heavens-Above, a non-profit website and mobile application that tracks satellites, the International Space Station (ISS), comets, and astronomical events in real time.

Another website that provides live information, including an orbit map on Tianhe-1, is NY2O.com. Check its menu list on the right side of the page and look for the blue box: "10-Day Predictions for CSS (Tianhe-1)."

Helpful hints for young telescope viewers

In the September 2019 issue of The Astronomical League Magazine "Reflector," author Richard W. Schmude Jr., offered some tips for those who plan to do public outreach for astronomy on Halloween:

"Firstly, children sometimes grab or touch the eyepiece, so use an inexpensive one. I gently warn children not to touch the telescope. In my area, parents have learned to tell their children not to touch the telescope. In some cases, a child will grab the eyepiece, causing the telescope to shift. For this reason, a Dobsonian telescope with a good finderscope is a good choice for Halloween outreach. A small stool or booster ladder may help very small viewers. Sometimes, parents hold their children up to look through the eyepiece. One may also place a monitor-connected video camera in the telescope and people can easily see the object on a screen." "Finally," adds Mr. Schmude, "I have my bag of goodies next to my telescope so that the children get two treats!"

Whatever your weather, Happy Halloween from all of us at Space.com!

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.