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Lagniappe for February 2025
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By NASA
5 min read
February’s Night Sky Notes: How Can You Help Curb Light Pollution?
Light pollution has long troubled astronomers, who generally shy away from deep sky observing under full Moon skies. The natural light from a bright Moon floods the sky and hides views of the Milky Way, dim galaxies and nebula, and shooting stars. In recent years, human-made light pollution has dramatically surpassed the interference of even a bright full Moon, and its effects are now noticeable to a great many people outside of the astronomical community. Harsh, bright white LED streetlights, while often more efficient and long-lasting, often create unexpected problems for communities replacing their old street lamps. Some notable concerns are increased glare and light trespass, less restful sleep, and disturbed nocturnal wildlife patterns. There is increasing awareness of just how much light is too much light at night. You don’t need to give in to despair over encroaching light pollution; you can join efforts to measure it, educate others, and even help stop or reduce the effects of light pollution in your community.
Before and after pictures of replacement lighting at the 6th Street Bridge over the Los Angeles River. The second picture shows improvements in some aspects of light pollution, as light is not directed to the sides and upwards from the upgraded fixtures, reducing skyglow. However, it also shows the use of brighter, whiter LEDs, which is not generally ideal, along with increased light bounce back from the road. City of Los Angeles Amateur astronomers and potential citizen scientists around the globe are invited to participate in the Globe at Night (GaN) program to measure light pollution. Measurements are taken by volunteers on a few scheduled days every month and submitted to their database to help create a comprehensive map of light pollution and its change over time. GaN volunteers can take and submit measurements using multiple methods ranging from low-tech naked-eye observations to high-tech sensors and smartphone apps.
Globe at Night citizen scientists can use the following methods to measure light pollution and submit their results:
Their own smartphone camera and dedicated app Manually measure light pollution using their own eyes and detailed charts of the constellations A dedicated light pollution measurement device called a Sky Quality Meter (SQM). The free GaN web app from any internet-connected device (which can also be used to submit their measurements from an SQM or printed-out star charts) Night Sky Network members joined a telecon with Connie Walker of Globe at Night in 2014 and had a lively discussion about the program’s history and how they can participate. The audio of the telecon, transcript, and links to additional resources can be found on their dedicated resource page.
Light pollution has been visible from space for a long time, but new LED lights are bright enough that they stand out from older street lights, even from orbit. The above photo was taken by astronaut Samantha Cristoforetti from the ISS cupola in 2015. The newly installed white LED lights in the center of the city of Milan are noticeably brighter than the lights in the surrounding neighborhoods. NASA/ESA DarkSky International has long been a champion in the fight against light pollution and a proponent of smart lighting design and policy. Their website (at darksky.org) provides many resources for amateur astronomers and other like-minded people to help communities understand the negative impacts of light pollution and how smart lighting policies can not only help bring the stars back to their night skies but make their streets safer by using smarter lighting with less glare. Communities and individuals find that their nighttime lighting choices can help save considerable sums of money when they decide to light their streets and homes “smarter, not brighter” with shielded, directional lighting, motion detectors, timers, and even choosing the proper “temperature” of new LED light replacements to avoid the harsh “pure white” glare that many new streetlamps possess. Their pages on community advocacy and on how to choose dark-sky-friendly lighting are extremely helpful and full of great information. There are even local chapters of the IDA in many communities made up of passionate advocates of dark skies.
DarkSky International has notably helped usher in “Dark Sky Places“, areas around the world that are protected from light pollution. “Dark Sky Parks“, in particular, provide visitors with incredible views of the Milky Way and are perfect places to spot the wonders of a meteor shower. These parks also perform a very important function, showing the public the wonders of a truly dark sky to many people who may have never before even seen a handful of stars in the sky, let alone the full, glorious spread of the Milky Way.
More research into the negative effects of light pollution on the health of humans and the environment is being conducted than ever before. Watching the nighttime light slowly increase in your neighborhood, combined with reading so much bad news, can indeed be disheartening! However, as awareness of light pollution and its negative effects increases, more people are becoming aware of the problem and want to be part of the solution. There is even an episode of PBS Kid’s SciGirls where the main characters help mitigate light pollution in their neighborhood!
Astronomy clubs are uniquely situated to help spread awareness of good lighting practices in their local communities in order to help mitigate light pollution. Take inspiration from Tucson, Arizona, and other dark sky-friendly communities that have adopted good lighting practices. Tucson even reduced its skyglow by 7% after its own citywide lighting conversion, proof that communities can bring the stars back with smart lighting choices.
Originally posted by Dave Prosper: November 2018
Last Updated by Kat Troche: January 2025
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By European Space Agency
Week in images: 03-07 February 2025
Discover our week through the lens
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By Space Force
DAF leaders announced the finalists of the 2025 Spark Tank competition made up of premier innovation ideas by Airmen and Guardians seeking sponsorship to bring their concepts to life.
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By NASA
4 min read
What You Need To Know About the March 2025 Total Lunar Eclipse
The Moon will pass into Earth’s shadow and appear to turn red on the night of March 13 or early in the morning of March 14, depending on time zone. Here’s what you need to know about the total lunar eclipse.
The March 2025 total lunar eclipse will take place between late night on March 13 and early morning on March 14 across several time zones. In this data visualization, the Moon moves from right to left, passing through Earth’s shadow and leaving in its wake an eclipse diagram with the times (in UTC) at various stages of the eclipse. Credit: NASA’s Scientific Visualization Studio What is a lunar eclipse?
A lunar eclipse occurs when the Sun, Earth, and Moon align so that the Moon passes into Earth’s shadow. In a total lunar eclipse, the entire Moon falls within the darkest part of Earth’s shadow, called the umbra. When the Moon is within the umbra, it turns red-orange. Lunar eclipses are sometimes called “Blood Moons” because of this phenomenon.
Alignment of the Moon, Earth, and Sun during a lunar eclipse (not to scale). NASA’s Scientific Visualization Studio How can I observe the eclipse?
You don’t need any special equipment to observe a lunar eclipse, although binoculars or a telescope will enhance the view. A dark environment away from bright lights makes for the best viewing conditions.
This eclipse will be visible from Earth’s Western Hemisphere.
Map showing where the March 13-14, 2025 lunar eclipse is visible. Contours mark the edge of the visibility region at eclipse contact times, labeled in UTC. NASA’s Scientific Visualization Studio What can I expect to observe?
Milestone: What’s happening: Penumbral eclipse begins (8:57pm PDT, 11:57pm EDT, 03:57 UTC) The Moon enters the Earth’s penumbra, the outer part of the shadow. The Moon begins to dim, but the effect is quite subtle. Partial eclipse begins (10:09pm PDT, 1:09am EDT, 05:09 UTC) The Moon begins to enter Earth’s umbra and the partial eclipse begins. To the naked eye, as the Moon moves into the umbra, it looks like a bite is being taken out of the lunar disk. The part of the Moon inside the umbra will appear very dark. Totality begins (11:26pm PDT, 2:26am EDT, 06:26 UTC) The entire Moon is now in the Earth’s umbra. The Moon will turn a coppery-red. Try binoculars or a telescope for a better view. If you want to take a photo, use a camera on a tripod with exposures of at least several seconds. Totality ends (12:31am PDT, 3:31am EDT, 07:31 UTC) As the Moon exits Earth’s umbra, the red color fades. It will look as if a bite is being taken out of the opposite side of the lunar disk as before. Partial eclipse ends (1:47am PDT, 4:47am EDT, 08:47 UTC) The whole Moon is in Earth’s penumbra, but again, the dimming is subtle. Penumbral eclipse ends (3:00am PDT, 6:00am EDT, 10:00 UTC) The eclipse is over. Data visualization showing a telescopic view of the Moon as the March 2025 total lunar eclipse unfolds. Credit: NASA’s Scientific Visualization Studio Why does the Moon turn red during a lunar eclipse?
The same phenomenon that makes our sky blue and our sunsets red causes the Moon to turn reddish-orange during a lunar eclipse. Sunlight appears white, but it actually contains a rainbow of components—and different colors of light have different physical properties. Blue light scatters relatively easily as it passes through Earth’s atmosphere. Reddish light, on the other hand, travels more directly through the air.
When the Sun is high on a clear day, we see blue light scattered throughout the sky overhead. At sunrise and sunset, when the Sun is near the horizon, incoming sunlight travels a longer, low-angle path through Earth’s atmosphere to observers on the ground. The bluer part of the sunlight scatters away in the distance (where it’s still daytime), and only the yellow-to-red part of the spectrum reaches our eyes.
During a lunar eclipse, the Moon appears red or orange because any sunlight that’s not blocked by our planet is filtered through a thick slice of Earth’s atmosphere on its way to the lunar surface. It’s as if all the world’s sunrises and sunsets are projected onto the Moon.
During a total lunar eclipse, the Moon is reddened by sunlight filtered through Earth’s atmosphere. NASA’s Scientific Visualization Studio What else can I observe on the night of the eclipse?
Look to the western sky on the night of the eclipse for a glimpse of planets Jupiter and Mars. The Moon will be in the constellation Leo, under the lion’s hind paw, at the beginning of the eclipse; soon afterward, it will cross into the constellation Virgo. As Earth’s shadow dims the Moon’s glow, constellations may be easier to spot than usual.
Visit our What’s Up guide for monthly skywatching tips, and find lunar observing recommendations for each day of the year in our Daily Moon Guide.
Read more: The Moon and Eclipses
Writers: Caela Barry, Ernie Wright, and Molly Wasser
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Last Updated Feb 06, 2025 Related Terms
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