Stellar Saturdays · the week's best pictures from off-world

From The Decisional Pass

Two of the best pictures released this week came from a jet and an 8-metre telescope. Neither one is really a story about a camera.

The jet that chased the shadow

Back on August 11 I wrote up the eclipse as a scheduled exam for a physics model. The answer sheets are arriving now, and they look like this.

That's the view from the cockpit of NASA's WB-57F high-altitude research aircraft, off the coast of Iceland, on August 12, the day the Moon's shadow crossed Greenland, Iceland and Spain. NASA ran it as Astronomy Picture of the Day this morning. The sky is dark because the aeroplane is inside that shadow. The horizon is bright because the shadow only covers so much ground.

The jet flew at 50,000 feet, along the computed path of totality, deliberately, to stretch its time in the dark. Totality was never generous: 2 minutes and 18 seconds at the very best, at a point about 45 kilometres off Iceland's west coast. You cannot make the Moon move slower, but you can drive underneath it in the same direction.

Altitude buys the other half. Above 50,000 feet you are over most of the cloud, dust and water vapour, and water vapour is the thing that eats infrared. Those are wavelengths you simply cannot collect from a beach in Spain.

Here's the part that stuck with me. It is a two-seat aeroplane and both seats had a job. Pilot John Gustine held the aircraft on the line as the shadow moved. Cary Klemm, sensor equipment operator, worked the back seat, controlling the camera systems, adjusting focus and exposure times, tracking features of interest, while the most photographed two minutes in astronomy happened outside the canopy.

I've done the ground-side version of that job. You get one pass, the geometry is fixed months out, and the window does not care whether your instrument is behaving. Everything upstream is planning: teams worked out where the aircraft had to be as the shadow crossed the North Atlantic well before anyone took off. Tom Parent, another of the WB-57F pilots, put it as months of working to the science team's requirements, plus a maintenance crew getting the instruments serviced and loaded. The actual event is somebody with their hands on a control, not blinking.

The science lead is Amir Caspi at the Southwest Research Institute in Boulder, whose team gets the corona in visible, near-infrared, short-wave and mid-wave infrared. Caspi put the case for flying plainly: high-altitude access mattered "during an eclipse whose path crossed mostly over the ocean in an area where clouds are common."

What they're chasing is an old, embarrassing question. The Sun's visible surface runs a few thousand degrees. The corona above it runs to millions, and nobody has fully settled why the thin outer atmosphere is so much hotter than the thing heating it. An eclipse is one of the few chances to watch that layer without the surface glare drowning it out, which is why two minutes is worth a transatlantic ferry flight. The same plasma-and-magnetic-field physics turns up all over the universe, and closer to home it feeds space weather forecasting.

NASA ended up watching the same eclipse from three heights on the same afternoon. Photographers on the ground in Spain. The jet at 50,000 feet. And Jessica Meir aboard the ISS, 262 miles up over southern Quebec, where the Moon covered about 18% of the Sun.

Six teenagers picked the target

The other picture of the week is this one, released September 1.

That's NGC 7253, two spiral galaxies more than 200 million light-years away in Pegasus, caught mid-collision and separated by roughly 4 million light-years. Gemini North on Maunakea took it. The pink knots are H II regions, hydrogen lit up by stars that only exist because the two galaxies are wrecking each other's gas.

The name on it is Nā ʻUhane Māhoe Huki Pū i ke Ola, "The Twin Spirits Pulling Together Creating Life."

Six high-school students from Hawaiʻi Island put it there. In October 2025, Project Hōkūlani interns Raiyan Rahman, Rafan Rahman and Alia Tamanha spent a week at the Gemini North Hilo Base Facility learning how the observatory actually runs, then chose what it would photograph. Rahman said they picked NGC 7253 partly because it was one of the few candidates sitting inside a Hawaiian constellation, Ka Lupe o Kawelo. In June 2026, Mylin Wilson, Manu Silva-Sampaio and Samantha Silva-Sampaio researched galaxy mergers and named the result.

It went out through the NOIRLab Legacy Imaging Program, which has been dedicating telescope time purely to making public colour images since 2002.

Both of this week's pictures had somebody deciding where to look. A crew flying a line drawn on a chart weeks earlier. Six teenagers with a target list and a reason. The optics are the easy part. Somebody has to point it.

— Elio

References

• APOD: Chasing the Moon's Shadow — NASA, September 5, 2026
• NASA Shares Views of August Solar Eclipse from Ground, Air, Space — NASA Science, August 21, 2026
• NASA Johnson Pilots Chase Moon's Shadow for Eclipse Science — NASA, August 26, 2026
• Project Hōkūlani interns researched and named this new Gemini North image — NSF NOIRLab, September 1, 2026
• Nā ʻUhane Māhoe Huki Pū i ke Ola — NSF NOIRLab image noirlab2621a, September 1, 2026
• APOD: Nā ʻUhane Māhoe Huki Pū i ke Ola — NASA, September 4, 2026
• Total Solar Eclipse on August 12, 2026 — NASA Science

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