CIRCLE WITH A DOT

@sundogplanets @leafgreen @BobLefridge that sounds reasonable

Today's #APOD demonstrates the highly damaging effect of satellites on astronomical photography. Long exposures end up looking like the Tholian Web. Can you find the comet tails amongst the noise? https://apod.nasa.gov/apod/ap260427.html @sundogplanets

Comet R3 PanSTARRS Behind Satellite TrailsImage Credit & Copyright: Uli FehrExplanation: Can you find the comet? Somewhere through this web of satellite trails is Comet C/2025 R3 (PanSTARRS), a bright visitor passing through the inner Solar System. Now, the orbiting satellites themselves only appear as streaks because of the long camera exposure, over 10 minutes in this case. On the contrary, to the eye, satellites appear as points that drift slowly across the night sky and shine by reflecting sunlight -- primarily just after sunset and before sunrise. The featured image was taken just before sunrise two weeks ago from Bavaria, Germany. Presently, Comet R3 PanSTARRS is hard to see for even another reason -- because it is so (angularly) close to the Sun. As the comet rounds the Sun, it will be best seen in coming weeks from southern hemispheree skies, although then it will be heading out to interstellar space and fading. If you haven't yet found the comet, don't despair; please take a closer look just above the image center.https://apod.nasa.gov/apod/ap260427.html #apod

The Persistence of SunlightImage Credit & Copyright: Lorenzo BusilacchiExplanation: This seaside sunset offered a surreal experience, captured in a sea and skyscape from the west coast of Sardinia, Italy, planet Earth. The Daliesque scene is a composition of sequential exposures made with a camera and long telephoto lens. The Sun is not melting, though. Its shifting and fluid appearance as it nears the horizon is caused as refraction along the line of sight changes and creates distorted images or mirages of the reddened solar disk. The changes in atmospheric refraction correspond to atmospheric layers with sharply different temperatures and densities. Another famous but fleeting effect of atmospheric refraction produced by a long sight-line to the setting (or rising) Sun is often called the green flash.https://apod.nasa.gov/apod/ap260425.html #apod

Three Sky Arches over Snowy AlpsImage Credit & Copyright: Angel FuxExplanation: Why are there three arches across the sky instead of two? Last month, after being dropped off by a helicopter at a high mountain peak in the Alps near the Swiss Italian border, an adventurous astrophotographer expected two arches of our Milky Way galaxy to be visible during the night. These were the inner arch looking in toward the center of our galaxy on the left, visible just before sunrise, and the outer arch on the right visible just after sunset. But there were three arches. The surprised astrophotographer soon realized that the sky was so dark that an entire arc of faint zodiacal light was also noticeable -- sunlight scattered by inner Solar System dust. And it artfully connected the two Milky Way arches! The next morning a helicopter picked the astrophotographer back up, and after 40 hours of processing and combining that night's images, the featured triple-arch 360-degree panorama resulted.https://apod.nasa.gov/apod/ap260421.html #apod

The ISS Transits the MoonImage Credit & Copyright: Sébastien BorieText: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)Explanation: Nope, that is not an alien spaceship landing on the Moon! This is an image of the International Space Station (ISS) as it begins to transit in front of the Moon. The ISS is in low-Earth orbit (LEO) where it wizzes around the Earth every 90 minutes. Orbiting the Earth 16 times per day for 25 years, the ISS has photobombed many familiar celestial objects including Venus, Mars, Saturn, and the Sun. Thousands of experiments led by researchers from over one hundred countries have been conducted on the ISS. Growing protein crystals in low gravity was one of the first experiments onboard the ISS and continues to contribute to new medical treatments. ISS astronauts study plant growth, water recycling, human health, and more to support the Artemis missions which will take humans farther than they’ve ever gone before. Next time you are out and about at night, try to spot the ISS zooming across the sky!https://apod.nasa.gov/apod/ap260415.html #apod

The Long Wispy Tail of Comet R3 (PanSTARRS)Image Credit & Copyright: Haythem HamdiExplanation: Why does Comet R3 (PanSTARRS) have a wispy tail? The newest bright member of the inner Solar System, Comet C/2025 R3 (PanSTARRS) is already extending an impressive stream of glowing gas. This tail starts from an unseen central nucleus of dirty ice that is likely a few kilometers across. The nucleus is warmed by the Sun and emits a cloud of neutral gas into a coma that glows light green. Nuclear gas ionized by energetic sunlight is pushed away from the Sun by the solar wind into an ion tail that glows light blue. The wispy nature of the ion tail is caused by the constantly changing structure of the solar wind. Pictured from Rhode Island, USA two days ago, Comet R3 (PanSTARRS) shows off a many-degree ion tail. Comet R3 (PanSTARRS) is best seen before dawn from northern skies for another 10 days, after which it will be best visible from southern skies.https://apod.nasa.gov/apod/ap260414.html #apod

NGC 602 and BeyondImage Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) - ESA/Hubble CollaborationExplanation: The clouds may look like an oyster, and the stars like pearls, but look beyond. Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the featured picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.https://apod.nasa.gov/apod/ap260413.html #apod

#NGC3310: A Starburst #SpiralGalaxy#Astronomy #Picture of the Dayhttps://apod.nasa.gov/apod/ap260405.html#APOD #Spiral #Galaxy

A Message from EarthImage Credit: Frank Drake et al., Arecibo Observatory;License: Arne Nordmann (Wikimedia)Explanation: What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory - then the largest single radio telescope in the world - a string of 1's and 0's representing the diagram was sent. This attempt at extraterrestrial communication was mostly ceremonial - humanity regularly broadcasts radio and television signals out into space accidentally. Even were this message received, M13 is so far away we would have to wait almost 50,000 years to hear an answer. The featured message gives a few simple facts about humanity and its knowledge: from left to right are numbers from one to ten, atoms including hydrogen and carbon, some interesting molecules, DNA, a human with description, basics of our Solar System, and basics of the sending telescope. Several searches for extraterrestrial intelligence are currently underway.https://apod.nasa.gov/apod/ap260329.html #apod