Author: daviddickinson

Press, Travel journal

New Comet ATLAS May Have Been an Old Visitor

Seen in 2019, Comet Y4 ATLAS may have solved a 19th century enigma… and started a new mystery.

Comet Y4 ATLAS

Hubble catches Comet Y4 ATLAS in the act of disintegration. Credit: NASA/Hubble/ESA Quanzhi Ye/Alyssa Pagan/STScI

In a clockwork universe, comets are the great wildcard, often appearing seemingly out of nowhere from the depths of the outer solar system.

Now, a new study links a recent comet with a breakup that may have occurred five millennia ago. The study out of the University of Maryland was published recently in The Astronomical Journal on July 21, 2021.

The story begins with the discovery of Comet C/2019 Y4 ATLAS on the night of December 28, 2019 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) automated sky survey in Hawai’i. ATLAS typically picks up a dozen-odd long period comets a year, most of which never reach naked eye brightness.

But Y4 ATLAS was different. The inbound comet was set to pass 0.77 Astronomical Units (AU) or 116 million kilometers from the Earth on May 23, 2020, and reach naked eye visibility at magnitude 0. As with so many comets however, said apparition never came to pass, as Comet Y4 ATLAS began to disintegrate on April 20th, shattering into 30 separate fragments. The Hubble Space Telescope was on hand to witness the disintegration, reminiscent to the string of comets from Shoemaker-Levy 9 that smacked Jupiter back in 1994.

The Great Comet of 1844

Now, it’s not uncommon for a dynamically new comet to disintegrate as it nears the warmth of the Sun for the first time. What did grab astronomer’s attention was the similarity of the orbital trace of Y4 ATLAS with another famous visitor: the Great Comet of 1844. This southern hemisphere comet was spotted from the Cape of Good Hope in early December 1844, and remained a naked eye object through the first half of 1845. Astronomer Maik Meyer first noticed the similarity between the two, leading astronomer Quanzhi Ye to hypothesize in the study that the two were fragments of a larger progenitor comet that broke apart around 5,000 years ago. And if the event occurred near perihelion—a prime time for comets to fall apart as they approach the Sun (remember comet ISON back in 2013?)—then our ancestors might have had quite a sky show, sometime back around ~3,000 BCE.

“If it broke up this far from the Sun, how did it survive the last passage around the Sun 5,000 years ago?” Says Ye in a recent press release. “It’s very unusual because we wouldn’t expect it. This is the first time a long-period comet family member was seen breaking up before passing closer to the Sun.”

Comets in 2021

Right now, we seem to be in a ‘comet drought,’ though comet C/2020 F3 NEOWISE put on a fine show last summer. You have to go all the way back over a generation now to the appearance of comets Hyakutake and Hale-Bopp in the late 1990s for the last truly spectacular ‘Great Comets…’ right before film photography gave way to digital imaging. And while there isn’t a great comet inbound yet, Comet C/2021 A1 Leonard may put on a solid showing in December 2021, shinning at +1st magnitude in the dawn.

Is a large chunk of comet related to Y4 ATLAS and the Great Comet of 1844 still out there? Perhaps… but we may have to wait five millennia to find out.

Press, Tips & News, Travel journal

Spitzer Spies Break in Milky Way Arm

A new study shows evidence for a previously unseen structure in our own Milky Way galactic neighborhood.

Milky Way Break

A break seen in the Milky Way’s inner arm. Credit: NASA/JPL-Caltech

Sometimes, it’s hard to see the forest through the trees. This is just the situation we’re in when we try to discern just what our Milky Way Galaxy might look like from the outside. Now, a new study looking at galactic structure noticed a gap in the Sagittarius spiral arm of the Milky Way that went previously unnoticed.Read more

Press, Travel journal

BepiColombo Completes First Mercury Flyby

The joint Japanese/European Space Agency’s Mercury mission encountered the innermost planet for the first time this past weekend.


Mercury (annotated) as seen from BepiColombo during Friday’s flyby. ESA

Welcome to Mercury. An ambitious mission completed its first flyby of its final destination this past Friday, as the joint JAXA/ESA BepiColombo made its first flyby of the innermost world.Read more

Tips & News, Travel journal

Top Astronomy Events for October 2021

October sees a parade of planets, meteor showers and more.

Dusk at the Nebraska 75th Annual Star Party in 2018. Credit: Dave Dickinson

October is one of my favorite months for astronomy. Not only are temperatures cooler in the northern hemisphere, but nights are getting longer: no waiting until past 10 PM for dark skies.Read more

Tips & News, Travel journal

Spire Satellites Ready for Solar Cycle 25


A unique constellation of nanosatellites provides real-time space weather data.

In space, sometimes looking down is the best way to look up. This is especially true of the interactive space weather environment, as our planet interacts with our often tempestuous host star. Our global modern technological society is increasingly vulnerable to space weather activity, and this is even more so as we head into active solar cycle #25.

Enter Spire

One effort to model and understand what’s happening worldwide is thanks to Spire Global Inc. And their constellation of Lemur satellites. Located in Sun-synchronous low Earth orbit, the first batch of Lemur satellite was launched on a Russian Dnepr rocket in 2014. Now boasting 110 satellites in LEO, Spire’s constellation is second in number only to SpaceX’s Starlink constellation.

How SPIRE works: Spire’s dataset is touted as ‘space-to-cloud’ offering a rich resource of weather patterns for maritime, aviation and other assets. Crucially when it comes to space weather, Spire can even model the upper ionosphere by means of over the horizon radio occultations. Often, turbulence (known as scintillation) can offset or knock out GPS capability entirely, especially during times of high solar activity.

And what’s more Spire Analytics is open to users. The National Oceanic and Atmospheric Administration recently awarded a contract to Spiral Global to provide daily radio occultation data in an effort to improve the accuracy of global weather forecasts worldwide. This is the largest purchase of commercial weather data by the NOAA to date.

This cloud computing weather capability will be key, as the current solar cycle number 25 gets underway in earnest. Our Sun goes through an 11-year cycle of sunspot activity (flipping its magnetic polarity in what’s known as the 22-year Hale Cycle). We had a breather with the last lackluster cycle 24. If early 2021 and recent sunspot activity is any indication, however, Solar Cycle 25 may be a powerful one as it heads towards its peak in 2025. Already this week, multiple large sunspot groups can be seen currently turned Earthward, the most in years.

Space Weather and the next ‘bad day’: A battery of space weather satellites and observatories worldwide monitor the Sun around the clock, but knowing what’s going on in the upper ionosphere is also crucial. An Earthward coronal mass ejection in the X-flare category can blind satellites, and force the crew on the International Space Station to shelter in the dense core of the ISS. On Earth, a massive solar storm can push aurora away from the poles, and wreak havoc with communications and transmission lines. The Great Solar Storm of 1859 set telegraph offices afire, and sparked aurorae seen as far south as the Caribbean. It goes without saying that today, a similar storm would be a very bad day for our technology dependent society.

Monitoring the space weather environment is crucial, and Spire’s innovative constellation of nano-satellites fills in a crucial gap in our holistic understanding of the local space weather environment.

Tips & News, Travel journal

How to Spot the Inspiration4 Mission in Orbit This Week

SpaceX’s historic all-civilian Inspiration4 mission is visible if you know when to look for it.

An artist’s impression of Inspiration4 in space. Credit: SpaceX.

Spaceflight will never be the same.

Tonight, Inspiration4 will launch from historic Launch Complex-39A on Wednesday, September 16th at 00:02 Universal Time (UT)/8:02 PM Eastern Daylight Saving Time (EDT). LC-39A also hosted Apollo and Space Shuttle era launches.

The crew consists of Jared Isaacman, Hayley Arceneaux, Christopher Sembroski and Sian Proctor. Money raised for the mission and proceeds are going towards St. Jude’s Hospital.

Crew Dragon Resilience will launch tonight atop a twice flown Falcon 9/Block 5 rocket. After launch and deployment, the Falcon Stage 1 booster will head for recovery on the Just Read the Instructions landing platform at sea.

The crew will spend a three day mission in space, set for splashdown landing in the Atlantic on Sunday Sept 19th and recovery by the SpaceX vessel GO Navigator.

Inspiration4 is headed toward Low Earth orbit (LEO), in an orbit similar to ISS inclined 51.6 degrees relative to the equator 590 km (370 mi) up, in a 90 minute orbit.

Spotting Inspiration4

The good news is, with a steep inclined orbit, Crew Dragon Resilience and Insiration4 will—like the International Space Station—be visible over most of humanity while it’s in orbit. And while the 8.1 meter-long capsule won’t be as bright as the brilliant station, it will be at decent +1 magnitude ‘star’ on a good zenith pass.

If the mission launches on time tonight, there’s also a good chance that the launch might even be visible as it travels up the U.S. East Coast minutes after liftoff. We’ve seen night launches from Florida from here in downtown Norfolk before, and they can put on an amazing display at dawn or dusk.

Heavens-Above should start tracking the launch once its in orbit, and it will probably turn up as NORAD COSPAR ID 2021-083A. Plugging in Two-Line-Element sets supplied courtesy of satellite tracker Marco Langbroek into Orbitron, we see good early passes for Inspiration4 favoring 20-50 degrees north latitudes at dawn, and 10N to 30S latitudes at dusk. We’ll be updating sighting opportunities worldwide on Twitter as @Astroguyz.

Watching for Dragon an Inspiration4 is as easy as standing out and scanning the sky at dawn or dusk, with no optical assistance needed: you just need to know what time and direction to look. Satellites in LEO shine via reflected sunlight, and look like steady moving ‘stars’ in the twilight.

Space is getting crowded, as the roll call of humans in orbit is the largest its been in recent years. This week, we have:

-7 crew members on the International Space Station

-3 crew on China’s new Tiangong station (though there’s word that the crew may return to Earth this coming Friday).

-4 crew on Inspiration4 for a grand total of 14 humanoids in space.

This briefly breaks the record of 13 people in space at once set in March 14, 1995, with 7 astronauts aboard STS-67 space shuttle Endeavor, 3 cosmonauts aboard Mir, and 2 cosmonauts and one astronaut aboard Soyuz TM21.

…and there’s more to come, as Axiom Space plans to partner with SpaceX on future tourist missions to the ISS, the first of which may launch as early as January 2022.

Is civilian space the wave of the future? Will the argument of ‘billionaires are ruining space’ rear its ugly head again, like it did during the recent crewed Blue Origin and Virgin Galactic flights? Are private astronauts referred to as ‘privonauts?’

Whatever your opinion is, you can at least catch Inspiration4 on a visible pass near you this week, and marvel at the potential for what may be to come.

Press, Travel journal

Impact Alert on Jupiter

Something struck the largest planet in the solar system last week.

Impact flash on Jupiter. Credit: the Société Lorraine d’Astronomie (Screen Capture).

It’s always worth keeping an eye out for the unexpected, even during routine observations. Just such a surreptitious occurrence happened just last week, when observers from South America to Europe caught sight of a bright flash on Jupiter.

The Impact: The event occurred around 22:39:37 Universal Time (UT) 6:39:37 AM Eastern Daylight Saving time (EDT) on September 13th in the equatorial zone of Jupiter. The event also happened to transpire during an ongoing shadow transit of the innermost Galilean moon Io, while it was casting its shadow back on to the cloud tops of Jove. Most likely, the flash was due to a comet or asteroid a few hundreds of meters across, burning up in the atmosphere of Jupiter. No impact scar was noted on the evenings after the event. The discovery sent observers around the world scrambling to review video and photos taken around the same time, yielding multiple confirming views of the same impact flash. News of the impact made its way around the astronomical community via online message boards and social media, most notably Twitter, the first place we heard about the sighting.

This impact occurred at an ideal time, as Jupiter just passed opposition early last month. As the name implies, this is the point when Jupiter is ‘opposite’ to the Sun as seen from the Earth, rising in the east as the Sun sets in the west. Orbiting the Sun once every 11 years, Jupiter reaches opposition once roughly every 13 months, moving about one constellation eastward along the zodiac annually as it does so. Jupiter is also a fast rotator, spinning on its axis once every 10 hours. This also means that you can see the entirety of the planet around opposition, in one night.

History of impacts: Of course, the memory of that most famous of all planetary impacts is still a fresh–that of Comet Shoemaker-Levy 9 hitting Jupiter back in 1994. At the time, it was thought that such impacts were relatively rare.. but no less than seven impacts have been witnessed on Jupiter in the quarter century since Comet Shoemaker-Levy 9 made its cosmic crash into Jove. This is a testament to the rise of modern planetary imaging and video technology, allowing for nearly constant coverage of the planet worldwide… how many impacts managed to sneak by the eyes of observers before the 21st century?

Current thinking among planetary astronomers is that Jupiter acts as a sort of goal tender for the inner solar system, deflecting and taking hits from many of the incoming intruders from the distant outer solar system. In fact, any incoming comet stands about a 40% chance of having its orbit altered by Jove during a perihelion passage… this famously happened to Comet Hale-Bopp in the late 1990s, which had its orbit shortened by several thousands of years.

Be sure to keep a sharp eye out, even during routine astronomical observations… you never know what might just turn up.

Tips & News, Travel journal

Enter the Equinox: Top Astronomy Highlights for September 2021

September is equinox month. Nights are getting longer in the northern hemisphere, meaning more time under dark skies before the chill of northern hemisphere winter sets in.

The September Sky: The glories of the summer Milky Way still linger post dusk. Up north, the famous summer triangle asterism rides high, with the stars Deneb, Altair, and Vega at its three corners.

The biannual equinox is short for ‘equal nights,’ a moment twice a year (once in March and again in September) when the rotational pole of the Earth is at a 90 degree perpendicular angle to the Sun, and day and night are equal worldwide. The equinox season is also special for a few other reasons: One is because it also marks GEOSat eclipse season. This is the period of a few weeks on either side of the equinox where distant satellites in geostationary/geosynchronous orbit seem to flare briefly into visibility, before vanishing into Earth’s shadow. Another phenomenon to watch for near the equinox is a peak in aurora activity. This biannual surge used to be a complete mystery until it was explained by what’s known as the Russell-McPherron Effect, which posits that solar wind streams through fissures opened in the Earth’s magnetic field. This occurs because the opposing magnetic field of the Earth is at its weakest angle right around the equinox. In 2021, we’re just now coming off a profound solar minimum, as Solar Cycle #25 gets underway in earnest. The jury is still out on whether or not the next solar cycle will ‘dazzle’ or ‘fizzle,’ though we’ve already seen some heightened solar activity worldwide in late August.

The Moon in September 2021: First Quarter Moon occurs on September 13th, and Last Quarter Moon occurs on September 28th, meaning the dark of the Moon (the best times for deep sky observations in the evening) runs from the 1st to the 13th centered on New Moon around September 7th, and resumes at the end of the month on September 29th and 30th. Of course, the Moon is a fascinating object to study in its own right, especially near Quarter phase when mountains and craters stand out in sharp contrast along the daylight/terminator.

The Planetary Rundown for September 2021: This month offers a true treat for evening skywatchers, as every naked eye planet is visible immediately after sunset. Mars is toughest, at just 12 degrees from the Sun at the start of the month, well below Mercury and Venus to the west. The gas giant planets Jupiter and Saturn rule the night rising in the east, fresh off of opposition last month. As an extra challenge, try spotting +8th magnitude Neptune with binoculars or a telescope in Aquarius this month. Fun fact: Neptune was discovered in the same constellation in 1846 after predictions made by astronomer Urbain Le Verrier), and has only completed one orbit in the last decade since discovery.

Highlighted object (northern hemisphere) Messier 57 The Ring Nebula – it was one of the first deep sky objects I ever went after. Situated in the constellation of Lyra the Lyre, M57 is a fine planetary nebula located about midway between the bright stars Beta and Gamma Lyrae, making it an easy find. I can just spy the ‘ghostly doughnut’ of M57 with binoculars from a dark sky site, and it really jumps out in a telescopic view. M57 is located approximately 2,300 light-years distant.

What you’re seeing is a star at the end of it’s life, ejecting gas and dust in its final death throes back into space. A challenging +15th magnitude white dwarf sits in the center of M57. Our Sun may do the same about 5 billion years from now, though a 2013 study cast doubt on whether we will also one day host a planetary nebula for future denizens of the Milky Way to enjoy at star parties. Fun fact: the term ‘planetary nebula’ actually has very little to do with planets: rather, early astronomers such as Charles Messier thought they appeared ‘planetary-looking’ while he was compiling his famous deep-sky catalog… and the name stuck.

Highlighted object (southern hemisphere): The Wild Duck Cluster Messier 11 – Many observers tend to overlook open clusters, which is a shame. Often, these loose stellar groupings still have enough ‘punch’ to go after, even from light-polluted urban sites. One of my favorites is M11. I often think of it as in the constellation of Aquila as it lies just off of the Eagle’s tail, but it’s actually just across the border in the tiny constellation of Scutum the Shield.

M11 is at southern declination of just over -6 degrees, making it a fine object for either hemisphere. At 6,200 light-years distant, M11 lies in the Sagittarius Arm of the Milky Way, towards the galactic center. At the eyepiece, M11 has a ‘powdered sugar’ look.

Challenge object (Northern Hemisphere): While you’re in the constellation Lyra checking out M57, try and see if you can resolve the famous ‘Double-Double’ star Epsilon Lyrae. The quadruple system is about 1.5 degrees from the brilliant Vega. Splitting the 210” pair is easy, even in binoculars; the challenge is to split the ‘pair into pair(s),’ both of which are only about 2.5” apart. This amazing system lies 162 light-years distant.

Challenge object (Southern Hemisphere): It’s a true irony of the night sky. Red dwarf stars, the most common type of stars in the universe are too faint to see with the naked eye. One of the brightest is the +6.6 magnitude star AX Microscopium in the obscure constellation of the Microscope. This star is 12.9 light-years distant, and offers a fine example of a nearby solitary red dwarf to check off of your life observing list. The coordinates for AX Microscopium are: RA: 21 Hours 18’ 35”, Declination -38 Degrees 46’ 49”.

Top Astronomy Events for September 2021

7th-New Moon

14th-Mercury greatest elongation (27 degrees east of the Sun at dusk)

14th-Neptune at opposition

15th-GEOSat eclipse season

17th-Comet 6P/d’Arrest at perihelion (+9th magnitude, 93 degrees east of the Sun in Sagittarius at dusk)

20th-Full Harvest Moon

20th-762 Pulcova occults +7 magnitude star for Mexico and US, in the brightest asteroid stellar occultation for 2021.

22nd-Southward Equinox

23rd-Aurora season