Dennis Mammana: Bridge to Borrego Springs’ Dark Sky Legacy
Meet Dennis Mammana, a passionate astronomer with nearly five decades of experience in unraveling the mysteries of the cosmos. Dennis’s journey began in Easton, PA, where he was captivated by the launch of the first Earth-orbiting satellites in the late 1950s.
With a degree in physics and astronomy from Otterbein College, he pursued further studies at Vanderbilt University, where his research involved a year-long study of distant Seyfert galaxies. This journey culminated in a coveted one-year internship at the renowned Strasenburgh Planetarium.
Beyond academia, Dennis is an accomplished night sky photographer, earning an invited membership in
TWAN (The World at Night). His celestial images have graced international publications and NASA’s Astronomy Picture of the Day.
As a versatile public speaker, Dennis has captivated and enlightened audiences spanning the globe, from local gatherings to international venues, encompassing diverse age groups and backgrounds, and catering to both novice enthusiasts and seasoned experts. His expertise extends beyond conventional boundaries, as he has orchestrated numerous public observing and sky photo expeditions worldwide.
For over 32 years, STARGAZERS
, Dennis Mammana’s beloved column, has been a window to the cosmos.
Borrego Springs International Dark Sky Community
Notably, Dennis has a deep connection to Borrego Springs, the only International Dark Sky Community
in California. In 2009, he was honored as the Grand Marshal of the 44th Annual Borrego Days Desert Festival for his contributions to preserving its dark skies.
Q&A Interview with Dennis Mammana
1. What Inspired Your Astronomy Career?
Dennis
: I began looking at the stars when I was just 7 or 8 years old. My father and I spent time outdoors watching for the first satellites that were launched from Earth, and I fell in love with the stars. Not long after that I got a small telescope and began peering deeper into the sky. And, when my eighth-grade teacher presented a unit on astronomy, I was hooked, and I knew that’s what I wanted to do with my life!
2. In what ways has technology enhanced the stargazing experience for enthusiasts and the general public?
Dennis
: Over the past few decades, technology has trickled down from professional astronomy to amateur astronomers. Today, computerized telescopes, electronic imaging, remote observing, and more are being used nightly by thousands around the world. They are using small backyard telescopes to take photos that rival those of the largest observatories just a few years ago, and are doing valuable research on many cutting-edge topics in astronomy.
3. What technology trends do you foresee for the future?
Dennis
: If I were Isaac Asimov I might have a good answer for you… alas, I can only begin to imagine how technology will change astronomy in the future!
One way it might change for amateur astronomers is the use of adaptive optics in which the turbulence of our atmosphere is reduced to make our images sharper. I also suspect much more of astronomy will become robotic which, in a sense, is a shame since part of the magic of studying the universe is being outside under the stars.
4. Are you particularly excited about any specific stargazing or astronomical technologies, discoveries, events, or missions?
Dennis
: To me, the search for planets orbiting other stars is particularly exciting. As of today, we know of more than 5,500 planets in orbit around other stars, and astronomers are now using technology to study the atmospheres of those planets for signs of life. I was fortunate to co-author the first book on the search for these worlds
, so I may be a bit biased!
And, of course, large ground-based and spaceborne telescopes are growing at an unprecedented rate. The Hubble Telescope (which has been revolutionizing our concept of the universe since 1990) coupled with the recent launch of the James Webb Space Telescope and the upcoming 30- and 39-meter telescopes are ushering in a truly golden age of astronomy.
5. Are there any television shows, documentaries, or movies that you suggest to people who want to learn about Astronomy?
Dennis
: Of course, there are the standard Nova programs about space and astronomy—those are always excellent. And any books by Carl Sagan are at the top of my list!
As for movies, perhaps my favorite is the 1997 film “Contact” (story by Carl Sagan) in which Jodie Foster plays a radio astronomer in search of signals of extraterrestrial intelligent life, while Matthew McConaughey plays a Christian philosopher who, as her love interest, creates quite an intellectual struggle for her. While the plot is interesting, it’s the subtext (the constant conflict between science and belief) that captivates me.
6. What tools do you suggest for a beginner if they want to start learning more about astronomy?
Dennis : My first recommendation is to get out under the stars to begin learning constellations, the movements of the moon and planets, and how the sky changes during the weeks and months. There are plenty of apps to help, though I find them only marginally useful since information appears quite tiny on a smartphone.
I also recommend keeping up with my syndicated column “
Stargazers ”; if it doesn’t appear in the local newspaper, one can subscribe to it free via email. The “subscribe” button is tiny, and located at the bottom of each column near my photo.
Another way to learn is to visit your local planetarium, as well as become involved with your
local amateur astronomy club ; many communities have one!
7. What steps should Borrego Springs take to continue highlighting its dark sky designation? Is there another city that we should look to as an example?
Dennis
: I think that, for as small as it is, Borrego Springs is doing great in highlighting our International Dark Sky designation—it’s quite a selling point. As one who regularly sees people visiting here from around the world and participating in my Borrego Night Sky Tours
, I’m very happy about how many people have learned about us from the Chamber of Commerce, the State Park, ABDNHA and elsewhere.
8. What are your visions for the future of Borrego Springs as an International Dark Sky Community?
Dennis
: I hope we can continue to enjoy a dark sky in the face of increasing light pollution from cities around us. We must make sure that lighting in our town is aimed downward and shielded, and that any new buildings follow or exceed the strict ordinances put forth by San Diego County. Our dark sky is one of the reasons that many enjoy our desert town, and why many choose to live here. DarkSky (formerly the International Dark Sky Association) shares with the public many ways
we can help preserve our dark sky while, at the same time, having all the outdoor light we need and saving money on electricity.
9. What is the best time to visit Borrego Springs to get the best view of the sky?
Dennis
: There really is no “best time”. The sky during every season is always exciting, but the weather can be good or bad, just like anywhere else. In the summer months (for example July and August) we have the best view of the Milky Way, while in the winter months (January and February) we see some of the most brilliant stars of the entire year.
On average, Borrego does tend to see more clouds (and occasionally some rain) during the late summer and winter months, but this can be quite variable from year to year, and there is often no way to predict sky conditions any particular night until that night.
In Appreciation: Dennis Mammana’s Enduring Impact
We extend our sincere appreciation to Dennis Mammana for his time and dedication. His contributions to Borrego Springs’ Dark Sky Community and the field of astronomy are invaluable.
As we continue to explore the cosmos and protect our natural wonders, let’s remember the guiding light that Dennis Mammana has been for our community and stargazers worldwide.
Learn More About The Night Sky
By Dennis Mammana
•
June 2, 2026
By Dennis Mammana Week of June 7-13, 2026 During one of my recent night sky tours, an elderly guest gazed into the sky and asked if the stars ever move. He said the constellations look the same now as when he was a child, and he was convinced that nothing in the heavens ever changes. It was an excellent observation but one that didn't consider an important fact: Human time scales are considerably different than cosmic time scales. Even the healthiest of humans will live at most about a century, and during our lives, we measure time in seconds, minutes, hours, days, weeks, months, years and decades. The cosmos, on the other hand, has been around for nearly 14 billion years, and everything takes much longer to occur. To recognize changes in the universe, astronomers must think on a more cosmic scale. When we do, we find that the universe is remarkably active. Stars are forming, consuming their nuclear fuel, and dying, and all are racing through our galaxy at tremendous speeds. Expecting to see changes in any star's appearance or the shapes of constellations over even a full human lifespan just isn't possible. To understand this, consider Barnard's Star, visible only through a telescope from the Earth's Southern Hemisphere. This star tears through our galaxy at a speed of some 88 miles per second, yet from our terrestrial vantage point six lightyears away, Barnard's Star requires three and a half centuries to cross a segment of the sky only the width of your outstretched little finger. Of course, we can't watch this movement with our eyes — or even through powerful telescopes — but by using sophisticated earthbound and satellite technology, astronomers can precisely measure these stellar speeds and directions of motion. Measure the speeds and directions of enough stars, and we find some interesting patterns. For example, stars that appear roughly in the direction of the summer star Vega (now shining low in the northeastern sky after dark) seem to be spreading out from a central point, while those on the opposite side of the sky (near Sirius, setting in the southwest around sunset) appear to be converging on one another. What this means is fascinating. Our sun's own motion is carrying it (along with the planets of our solar system) toward the stars near Vega — a point we know as the solar apex — and away from those near Sirius (known as the solar antapex). This phenomenon isn't difficult to visualize. Imagine you're driving along a highway from one city to another. The buildings in front of you appear to become more widely separated as you approach, while those behind you appear to converge more tightly. This is exactly what's happening in our section of the galaxy. Our sun is moving at some 12 miles per second toward a point in our sky not far from the bright star Vega. Of course, we can't see this movement, but it's fun to stand outdoors on a clear night and imagine our sun and Earth racing outward toward Vega. Now, if you're worried about a collision with this star ... well, fuhgetaboutit. Even at this remarkable speed, we'd need some 5,300 human lifetimes to get there! Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. Learn More About Borrego Springs
By Dennis Mammana
•
May 21, 2026
By Dennis Mammana Week of May 24-30, 2026 When you hear the phrase "once in a blue moon," what do you think? If you're like most people, you think of something that doesn't happen often. So what exactly is a blue moon, and why is it so rare? First off, a blue moon isn't all that rare. It occurs on average about once every 2.72 years. Secondly, the moon doesn't appear blue at all; it's just a regular ol' full moon that happens to be the second one in any particular month. You know this phenomenon if you receive a paycheck every two weeks. You'll usually get two checks a month, but occasionally you'll receive a third. It's not that uncommon, and neither is a blue moon, despite the popular meaning of the term. A second full moon in a month occurs occasionally because our calendar isn't synced with the lunar phases, even though the word "month" derives from the word "moon". What we call a month — approximately one-twelfth of a year — is longer than the moon's "synodic" period — the average time between one full moon and the next (29.53059 days). So every once in a while — every blue moon, one might say — two full moons will occur during the same calendar month. We'll see the next one on Saturday night, May 30. Be sure to watch as the moon rises in the southeast just after sunset that night. Chances are that it will first appear rather orange or red because its light must pass through a long column of air on its way to our eyes, and normal particulate matter suspended in the air scatters the moon's light and colors it orange. Some have defined the blue moon differently. Most seasons of the year will experience three full moons, but occasionally a fourth will sneak in. In that case, the fourth of the season would be known as a "blue moon." This seasonal definition may have originated from a 1943 question-and-answer column in Sky and Telescope magazine in which Laurence J. Lafleur traced the term to a 1937 "Maine Farmers' Almanac." Three years later, it seems, folklorist Philip Hiscock wrote in the same magazine an article that gave birth to the "second full moon in a month" idea. Neither of these situations is particularly unusual, so where did the rarity idea originate? Occasionally, especially thick smoke or volcanic ash particles suspended in our atmosphere can remove enough red moonlight to make the moon appear bluish. It is said that, after the Krakatoa volcanic eruption in 1883, the moon appeared blue for more than a year. As you might imagine, this is extremely rare. In fact, one might say that it happens ... only once in a blue moon! Now there's one more thing about the full moon that we'll see this coming weekend. It reaches its orbital "apogee" at 4:45 a.m. EDT / 1:45 a.m. PDT, its farthest point from the Earth (about 250,517 miles away). This means that it will appear as the smallest full moon of this year. You might hear it called a blue "mini moon," though most stargazers won't be able to see much difference from a normal full moon. Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. Learn More About Borrego Springs
By Andrea McKenna
•
May 17, 2026
Experience the Walk of the Cosmos in Borrego Springs—a journey through the solar system in a beautiful desert park with playgrounds, sports courts, and stargazing opportunities.
By Dennis Mammana
•
May 12, 2026
By Dennis Mammana Week of May 17-23, 2026 That brilliant light now glistening in the west at sunset is again the "star" of the show. It is, of course, the planet Venus, and this week it'll pair up with two other celestial wanderers: Jupiter and the moon. Jupiter, another very bright planet, has been descending farther to the west as the spring months progress, and it is now approaching a close encounter with Venus by the end of the month. This occurs because these worlds, along with the Earth, orbit the sun, and our constantly changing viewpoint makes them appear to drift slowly against the more distant and "fixed" stars. Over the next week, though, another solar system body will enter the scene: the moon. Since our celestial neighbor orbits the Earth once a month, we can see it change its position in the sky from night to night. Shortly after sunset on May 17, you might try searching very low in the west for the tiny and delicate crescent moon, but to find it, you'll need a very clear sky and a low horizon, and possibly binoculars. If you don't succeed, don't worry. It'll be pretty tough to spot, but if you wait until the next night, it'll be much easier to see. On the 18th, it will appear not far from Venus. Of course, the moon won't really be next to this planet; they will be separated by 124 million miles that evening, but since both lie roughly along the same line of sight, they'll appear together in the sky. For a really amazing view, check out the pair through binoculars! The following night, May 19, the moon will have moved eastward along its orbit and will appear about midway between Jupiter and Venus. If your sky is clear on May 20, check out the western sky again, and you'll notice that the moon is not only a significantly thicker crescent but now lies above Jupiter. Of course, this whole view is purely an illusion caused by our inability to see true depth in the cosmos, but it does result in a truly pretty picture. And speaking of pretty pictures, this week offers a good opportunity to try your hand at photographing the spectacle. Since the trio appears low enough in the sky at dusk, you can frame the scene with a foreground subject — a dramatic tree, building, sculpture or person, for example. You don't need fancy or expensive equipment to do this; just a regular camera or smartphone will do fine. You may find, however, that zooming in a bit will produce a more compelling image. If you shoot half an hour or so after sunset, you can probably trust the automatic settings of your camera or phone. Much later, though, you may need to adjust settings as you go because the light at dusk changes rapidly. Don't be afraid to experiment; if some photos turn out poorly, you can always hit "delete," and no one will ever know! I hope your skies are clear this week so you can enjoy the planetary sky show. And if you get some nice photos, please email me. I'd love to share your success! Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. Learn More About Borrego Springs
March 18, 2026
By Dennis Mammana Week of March 22-28, 2026 Now that spring has sprung, I'm sure that those who have endured a long, cold and snowy winter are rejoicing. Anyone who knows me knows that I'm no winter person. Sure, I used to enjoy the season when I was a kid, but that's only because I could spend entire days building snow forts with my friends and making a few bucks shoveling the white stuff for neighbors. No longer. Today, warmer days of springtime can't come soon enough for me! If we had no calendar, we would still know the seasons are changing. We see it happening all around us: Temperatures are rising, the first flower buds are beginning to appear, and many birds are returning to our part of planet Earth. And, just as our daytime world gives us clues that spring is approaching, the darkness does as well. Nighttime hours are beginning to shorten, and the brilliant stars of winter are descending in the west to make way for those of springtime. And no star grouping heralds the arrival of springtime to our Northern Hemisphere more than Leo, the lion. Head outdoors during early evening hours and cast your gaze midway up in the eastern sky. There, you'll see Leo, one of the few constellations that, with some imagination, actually can be made to look like its namesake — a lion crouching in a regal pose reminiscent of the enigmatic Egyptian Sphinx. Most prominent in this constellation is the bright star Regulus, which shines brightly beneath the lion's majestic head and mane, outlined by a large sickle-shaped grouping of stars. More metropolitan stargazers may recognize this figure not as a sickle but as a backward question mark, with Regulus forming the dot at its base. The star's very name, "Regulus," comes from the Latin word "Rex," meaning "king," and, interestingly, this star was revered throughout the ancient world as a "royal" star. According to astronomy author R.A. Allen, it was known in Arabia as "Malikiyy" (the Kingly One), while the ancient Greeks knew it as "the Star of the King." At the other end of the lion, we find the bright star Denebola, whose name originates from the Arabic "Al Dhanab al Asad," meaning "The Lion's Tail." You can find Leo more easily if you use the two pointer stars of the Big Dipper, farther to the northeast. These stars point toward Polaris (the north star) if you follow them from the bottom to the top of the Dipper's bowl, but if you follow them in the opposite direction, you can find your way toward the back of the lion. If you have trouble tracing this animal's shape among the stars, don't worry. Just turn it around and you'll find it's much easier to find not the mighty king of the jungle but instead a mouse! Quite frankly, I think the figure of a mouse is much easier to trace. Here, the star Denebola forms its pointy nose, the nearby triangle forms his head, and the sickle now outlines its long, curving tail. Either way you look at it — mouse or lion — nothing in the heavens announces springtime more loudly than Leo! Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. Learn More About Borrego Springs
March 6, 2026
By Dennis Mammana Week of March 8-14, 2026 If you hear the word "superstar," what immediately comes to mind? Perhaps names like Tom Hanks, Taylor Swift or LeBron James? That's certainly understandable; they are all undisputed superstars who attract the attention of paparazzi and fans alike. If you're an astronomer, however, you may answer this question differently. For example, when I hear the word "superstar," I think of UY Scuti, WOH G64 or RSGC1-F01. Yes, these are superstars, but not quite how people may think. These are some of the largest stars known in our galaxy and, for that reason, are quite intriguing to us celestial paparazzi. Regular readers of this column know that our sun is also a star. It appears big and bright in our daytime sky because not only is it rather close (about 93 million miles away), it's also pretty large (nearly a million miles across). It sounds huge, but our star is rather small on a cosmic scale, and believe it or not, there are stars out there that would dwarf our sun and make it look tiny. These are the true superstars! Until recently, the largest star known was given the hopelessly poetic name of UY Scuti. At a distance of some 9,500 lightyears from Earth, UY Scuti is what is known as a red hypergiant star, with a diameter some 1,700 times that of the sun! All that changed recently, however, when astronomers found a gargantuan star some 2,150 times larger than our sun! It's named Stephenson 2-18, and if you'd like to get a peek at this stellar behemoth, you'll need more than your eyes. At a distance of some 18,900 lightyears, it appears 5,100 times fainter than we can see without a telescope. If you have no telescope but would still like to see a celestial superstar, you're in luck. There's one shining in our night sky right now; it's one of the brightest up there and is named Betelgeuse. Betelgeuse sparkles brightly in the northeastern corner of Orion, the hunter, and you can see its orange light midway up in the southern sky after dark this week. With about 15-20 times more mass than our sun, Betelgeuse is known as a red supergiant star for good reason. While we could align 109 Earths across the face of our sun, we would need at least 700 suns to cross the face of Betelgeuse! Indeed, this star is so immense that if it replaced our sun at the center of our planetary system, Betelgeuse would engulf the orbits of Mercury, Venus, Earth and Mars, and stretch part of the way to Jupiter! Yet it appears as a simple point of light in our night sky because of its tremendous distance from us — some 3,100 trillion miles, or about 520 lightyears. Betelgeuse is easily one of the largest known stars, though its size fluctuates by as much as 60% as the star shudders and pulsates on its way to an eventual supernova explosion, thousands or millions of years from now. Or tonight. We just don't know. I hope you'll step out under the night sky soon to meet this remarkable superstar for yourself! Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. Learn More About Borrego Springs
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