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Dean Regas

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Occultation of Mars by the Moon

Cold Moon Occults Mars

See the Red Planet Snuffed Out
December 7, 10:20-10:52pm

As the Moon circles the Earth it can pass in front of bright stars, blocking their light completely.  This is called an occultation.  

But the Red Planet better watch out!  Because:

December 7 from 10:20-10:52pm Eastern Time the Moon will occult Mars.

Basically when you look up that night at 10:20 you will see this very bright orange-colored star – which is actually Mars – just below the full Moon.  One second it will be there, and the next ‘poof’ it will be gone.

For about 30 minutes Mars will be behind the Moon but will pop back into view as quickly as it was snuffed out.  

Adding to the rarity, the full Moon of December, nicknamed the “Cold Moon,” occurs at about the same time.  And Mars will be exceptionally bright since it will have reached its closest point to the Earth for the year.

The event will be visible across the country except in the southeastern quarter of the U.S.  And you don’t need binoculars or telescopes to see it (although they will help).  

This doesn’t happen very often.  In fact, in 25 years of viewing, I’ve never seen a Lunar Occultation of Mars.

Total Lunar Eclipse November 8, 2022 by Dean Regas



Taken by Dean Regas


Ault Park, Cincinnati, Ohio

November 8, 2022


The skies stayed clear enough to observe the eclipse from beginning to moonset.  When the eclipse began we could even see a faint halo around the Moon.  And during the eclipse several bright meteors streaked across the sky and the International Space Station passed overhead.  Quite an astronomical morning!

Shooting star

Orionid Meteor Shower

Peaks October 20-22

Each October the Earth slams into debris from Halley’s Comet and shooting stars crisscross the night sky radiating from the constellation Orion.  You may be thinking, “Wait, what?!? Why have I not heard about this before?”  

This is the Orionid Meteor Shower which peaks around October 20-22 and although it sounds cool (and is unbelievably cool) it generally does not put on a mind-blowing display of lights and fireballs – and it’s best seen between 2-5am – and the Moon has to be out of the way – and you have to be away from city lights.  

But with all those caveats, this Orionid Meteor Shower could be decent.  The moonlight will not interfere much since it is near the New Moon.  And the peak takes place over the weekend so you can stay up late, get out to the countryside, and actually enjoy unseasonably warm weather.

But, don’t believe websites that claim you will see 50-100 meteors per hour.  Lower your expectations and hope for about 12 per hour (or about one shooting star every 5 minutes).  

Orionid Meteor Shower
•    Best viewing Friday night 11pm to Saturday morning 5am
•    And again Saturday night 11pm to Sunday morning 5am
•    Face east before midnight, then follow Orion after midnight to see the max meteors
•    No binoculars or telescopes needed
•    Kick back in a comfy chair and take in as much of the sky as possible
•    Be patient.  Meteors often come in spurts with long lulls in between

Members of the Cincinnati Observatory will hold Orionid Meteor Shower viewing and set up telescopes at Stonelick State Park on Saturday October 22 after sunset.  It is free and open to the public. 
For More Info on Stonelick Star Gazes

First Quarter Moon

Sunday October 2, 2022

From the Cincinnati Observatory

What a lovely evening for a moonwatch!  I invited some people over - who were clouded out for International Observe the Moon Night on Saturday - to see the Moon, Jupiter, and Saturn with me on Sunday.  The conditions were so perfect that I hooked my phone up to a little refracting telescope outside the Observatory and just sat and watched.  The motion you see in the video is the Earth rotating.  As our planet spins, the Moon appears to move from east to west.  Click to make it full-screen and check out those craters!

Dean Regas - Astronomer in Residence

At Grand Canyon National Park

I am returning to the Grand Canyon June 20-23 to take part in the annual Star Party.  I'm giving some talks and then 50-100 astronomers set up telescopes for the public to view.  More than 1,000 people look through telescope each night.  It is a real STAR PARTY!

To the right is an interview I did, right on the edge of the South Rim in Fall 2021 during my month-long Astronomer in Residency at the Grand Canyon.

And you can Listen to Dean Regas talk about the Astronomy in Residence program on Science Friday

Total Lunar Eclipse

Total Lunar Eclipse 

My adventure to chase totality

On Sunday May 15, 2022 the weather forecast for the total lunar eclipse was not looking good for Cincinnati.  So I searched the weather maps for the closest place that could have clear skies.  That place looked to be Portsmouth, Ohio - about a two hour drive.  I packed up the car and the eclipse chase was on!

As I drove east at sunset I beheld a glorious sight - the Full Moon rising above the treetops, pink and huge, and clear.  I thought I had chosen wisely to drive east.  Then some clouds rolled in and before I reached Portsmouth after dark, the Moon was covered in haziness.  Dang it!

But as expected, the clouds lifted as the Moon rose higher and I set up my telescope at Riverfront Park on the south side of the floodwall.  The Ohio River was flowing in front of my and the Moon hung over the long bridge connecting Ohio to Kentucky.  And at then I saw the whole thing!  

Lunar Eclipse Timing (Eastern Time)

  • Partial lunar eclipse began: 10:27pm
  • Total eclipse began: 11:29pm
  • Deepest, darkest part of the eclipse: 12:11am
  • Total eclipse ended: 12:53am
  • Partial lunar eclipse ended: 1:55am

The excitement will began at precisely 10:27pm EDT when the first hint of the Earth’s darker shadow, called the umbra, appeared on the disc of the Moon.  That is the rounded shadow of the Earth.  If the moment strikes, you may howl!  I stayed out there until totality when the Moon turned so dark that it was nearly invisible.  I had never seen such a dark lunar eclipse.  A little after midnight, I packed up and headed back home.  Along the way I could see the eclipse continuing out my driver's side window.  This was my 20th lunar eclipse.  And totality was totally worth it!

The Crescent Moon

Through the Mitchel Telescope

At the Cincinnati Observatory

April 6, 2022

The clouds were traveling quickly in front of the Moon that night.  But there were enough breaks in the clouds that I pointed the historic Mitchel Telescope at the Moon, attached my phone, and captured this video.  Notice the impact craters and moutain ranges in sharp contrast along the terminator (the line that separates the dark side from the light side).  You can maximize the window to get the best view.

On April 16 look for the Full Moon after sunset and and see if you can take a picture of it as it rises above the eastern horizon.

Rocket Hits The Moon

A mysterious spent rocket body crashed onto the farside of the Moon Friday, March 4 at 7:25am (EST).  Astronomers first spotted it in 2015 but were not 100% certain whose rocket it is.  Most believe it is a Chinese-made Long March 3C rocket body which launched the Chang’e-5 T1 spacecraft toward the Moon in 2014.  It has since been spiralling around the solar system and became caught in the Moon's gravity.

Friday morning slammed into the lunar surface at around 5,700 miles per hour.  Unfortunately, since it impacted a side of the moon not visible from Earth, we couldn't observe the blast with backyard telescopes. Instead, astronomers hoped to witness the fall using robotic crafts orbiting the moon. NASA's Lunar Reconnaissance Orbiter (LRO) and India's Chandrayaan 2 may have been positioned to observe the impact site and, hopefully, the crash itself.

How big was the blast?  What kind of crater did it leave?  Stay tuned for updates and, hopefully, pictures.

Dean's Article About the Rocket Crash

Cast of Don't Look Up movie

Please Look Up

Dean Regas reviews Don't Look Up

I watched Netflix’s movie, Don’t Look Up twice: once as a movie patron and again as an astronomer.  I’m always interested in how movies portray astronomers and after two viewings, I’m happy to say we came out looking like the normal ones (maybe the only normal ones). 

Note: This review is for people who have already seen the movie, so I won’t rehash the plot. But that also means spoilers are definitely ahead.

Does studying the universe give you a unique worldview?  In Don’t Look Up, that was definitely a theme.  In a world of filled with the social media-obsessed, the fame-driven, the politically-ambitious, the bellicose, and everyone in between, the astronomers were the only voices of reason.

Astronomers Behaving Well

I will say that the astronomers depicted in the movie do not fully represent my colleagues or the field as a whole.  But these were the scenes where I thought the movie nailed it.

In the opening scene, Kate Dibiaski (Jennifer Lawrence) displays the true wonder and emotion when she first sees her comet.  This is what astronomy is all about: searching and, if you’re lucky and good, finding.  It was perhaps one of the best movie scenes to depict the sheer joy of discovery.

Contrast that with the emotion of uncertainty, then certainty, then disbelief, and then terror that Richard Mindy (Leonardo DiCaprio) showed when his math exposed the nightmare scenario: that on paper, the comet was going to hit the Earth.  No CGI needed. His face was apocalyptic.


Want to discuss space movies? Join Dean For An Online Class March 8 called "Please Look Up"

Peter Isherwell character in Don't Look Up

Two Types of “Scientist”

Don’t Look Up also contrasts two types of scientists. The astronomers represent the pure scientist, forever looking, ever-curious.  They are in the dome, in the lab.  Classic. 

The second kind of scientist is demonstrated by eccentric tech-wizard Peter Isherwell (Mark Rylance), who embodies a conglomeration of Elon Musk, Steve Jobs, and Mark Zuckerberg.  Isherwell is the perfect user of science, the technologist who does things just to do them (and turn a profit).  Science and technology are really two sides of the same coin.  But the public in Don’t Look Up views them as separate entities - one group makes theories while the other makes our lives better.  To put in a more negative light, technologists are just like the astronomers only much more successful.

Isherwell’s “success” comes at a price: his soul.  He obviously does not have humanity’s best interests at heart.  His analytics tell him that a vast new pile of minerals on a dead planet is still a vast pile of minerals.

Life on Earth – Not Just Us

Although too short and oddly-timed, the montages of life on Earth impacted me.  By showing the various animal and plant life it reminded me that this planet is not just us.  The movie sucks you into human concerns so much that, I’ll admit, I didn’t even think about life other than humans.  It made me feel so human-centric.

It made me consider, for maybe the first time, we (humans) have a responsibility to all life on Earth.  If we fail, we fail not just us but everything that has evolved from the beginning of time on perhaps the only place life exists.  The weight of that responsibility can be overwhelming.

Ariana Grande and Kid Kudi in Don't Look Up

Apocalyptic Comedy

One of the most moving scenes was when Dr. Mindy and the public first see the comet with their own eyes.  Fear, beauty, wonder, the comet is horrific and glorious at the same time.  This is what ancient stargazers must have thought whenever a new, cometary guest emerged in their sky.  “Wow,” mixed with, “Uh oh…”

The apocalyptic comedy was at its best when President Orlean (Meryl Streep) smokes in front of a flammable truck while telling Dr. Mindy, “You’re with the grown ups now.”  And the benefit concert led by the astronomers and featuring Ariana Grande and Kid Cudi. The performance goes sideways so subtly as Grande rises up from the stage in a flowing, nebulous outfit.  It was only after five seconds, with my mouth agape, when I realized the supreme tone-deafness of the moment and yelled at the TV, “No!  No!  Oh my god, she’s the freaking comet.  Nooooooo!”

Interview scene from Don't Look Up

Astronomers Are Like Us

The movie shows the many true intersections between the world of astronomers and everyone else.  Astronomers shine under the domes and at their equipment.  However, the world of media, politics, and business are alien.

While a quaint idea and expedient to the plot, the movie put unrealistic gravity on the interviews with the morning show hosts Kate Blanchett and Tyler Perry.  There is no one TV show to which everyone watches.  The days of a live TV show going viral are extinct.

But I still thoroughly appreciated the interviews.  It so accurately shows the astronomers coming face to face with real people trying to make small talk.  “Wait,” the interviewers think – and you can see them think, “are they astrologers or astronomers?  Shoot, what’s the difference?”  This is followed by the voice in their heads screaming, “Don’t ask about aliens.  Don’t ask about aliens.”  

This was exactly what I experienced early in my career with media interviews about the latest discoveries.  I prepared myself with the facts and then, wham, the first question came at me, “So Dean, you can tell us.  Are there really aliens?”  Like Dr. Mindy, I quickly learned to be ready for any question, to “keep it simple”, “tell us what it is”, and “don’t use math.”

There were two major mistakes in the movie’s depictions of the astronomers. 1) The DiCaprio-Blanchett affair was pure fiction. True astronomers are generally immune to earthly seductions.  They are either oblivious to them or are simply not interested since their one and only love is the stars.  2) No observational astronomers would sit down for dinner as the comet fell. They would be at the closest point to the impact site and counting it down.  Astronomers’ fear of missing out is stronger than even the end of the world.

Dean Regas looking through the Mitchel Telescope at the Cincinnati Observatory

Do We Deserve to Survive?

As an astronomer, I’ve wondered, “Will I ever have to break this news to the public?” How would I relate the devastating news that an asteroid is going to destroy life on Earth and there is nothing we can do about it? 

I heartily believe in the parting words of the movie, “We really did have everything, didn’t we?”  Maybe that is where astronomers have a unique perspective.   With all of our studies of the heavens, astronomers have still not discovered one planet where life exists.  In fact, there is no place in the universe that we know of, outside Earth, where you can walk outside without a spacesuit and not die instantly and painfully.  We may someday find a hospitable planet, ready for us to move in, but it will be trillions of miles away and require a journey of 20,000 years.  We can’t run.  We can’t hide.  There is nowhere else for us to go (and subsequently be eaten by a bronteroc).

Earth has been struck by comets and asteroids before and it will be struck again.  But there’s good news: We are a point in history, for the very first time, that we can spot an incoming asteroid and do something about it.  We have the power to save the Earth.  Are we up to the challenge?  And as Don’t Look Up painfully askes, do we deserve to survive?


Want to discuss space movies? Join Dean For An Online Class March 8 called "Please Look Up"

Webb Telescope Reaches Lagrange

The James Webb Space Telescope launched on December 25 and headed into deep space.  It's destination, and home for the next decade, is Langrange Point 2 (L2) a spot about 1 million miles away where the gravitational pull of Earth matches that of the Sun.  L2 is a cozy spot for space telescopes to live and peer deep into the universe.  When fully operational in a few months, astronomers hope that Webb will provide unparalleled views of the heavens.

In honor of reaching the Lagrange Point, I merged this Webb Telescope video with my favorite ZZ Top song, La Grange.  I think you'll find the pairing both educational and entertaining, and that it gets your toes tapping and your eyes looking up.

Click Here For the Video

Cincinnati Libraries to Loan Telescopes

Cincinnati Observatory Astronomer Dean Regas is partnering with the Cincinnati and Hamilton County Libraries to offer the stars to library patrons.  Telescopes may be checked out from certain branch libraries starting this month.

Regas donated 10 telescopes to the libraries so that patrons can borrow them like checking out a book.  “My hope is that people will be inspired by their views through the telescopes and the universe,” Regas said.  

With just your library card you can sign up to reserve a telescope for a three-week period.  The telescopes are small but powerful and can show the craters on the Moon, the planets, and stars and star clusters up close. 

“I wished I had this at my local library growing up,” Regas said.  “Everyone should be able to explore the universe like this with friends and family.”

For more please see: This Link!

Partial Solar Eclipse 

Thursday June 10

I chased the eclipse in search of clear skies and better views and traveled to Mackinaw City, Michigan.  Luckily the clouds stayed away and I was able to get capture this video of the partially eclipsed Sun just above Lake Huron at sunrise. 

It is so awe inspiring and such an amazing sight to see the Moon block out part of the Sun.  The next solar eclipses visible from the United States will be October 14, 2023 and April 8 2024.  Mark your calendars and don't miss them!

Jupiter and Saturn Come Together

On the nights of December 20, 21, and 22 the largest planets in our solar system, Jupiter and Saturn, appeared closer together in the sky than they have since 1623.  In fact they were so close that you could see the two planets in a telescope at the same time!  

To the right is video captured by Astronomer Dean Regas through the Cincinnati Observatory's 175 year old telescope on December 21.

“Return of the Moon Joke Episode”

Classic Star Gazers Episode

From February 12-18, 2018

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