- Some of the highest resolution images of Jupiter ever obtained from the ground have been shot from the Gemini North telescope on Hawaii’s Maunakea volcano.
- There is also something new about Jupiter’s “Great Red Spot.”
- Astronomers call the technique for getting some of the sharpest-ever images of Jupiter from a ground-based telescope as “lucky imaging”.
Jamie Carter, writes for Forbes on the interesting aspect of Jupiter images shot from the Gemini North telescope on Hawaii’s Maunakea volcano. He elaborates on how varied kinds of excellent images of Jupiter is obtained.
Remarkably, when combined with those of the Hubble Space Telescope and NASA’s Juno mission at Jupiter, the resulting multi-wavelength images reveal lightning strikes.
The dramatic images are the result of combining three types of images over three years of observations:
- pin-sharp infrared images from Gemini North’s Near Infrared Imager (NIRI)
- optical and ultraviolet images by Hubble Space Telescope
- radio observations by NASA’s Juno spacecraft now orbiting Jupiter
So what do astronomers call the technique for getting some of the sharpest-ever images of Jupiter from a ground-based telescope? “We used a very powerful technique called lucky imaging,” said Michael Wong of UC Berkeley, who led the research team.
“Lucky imaging” is when lots of very short exposure images are taken and only the sharpest—taken at brief moments when the Earth’s atmosphere is stable—are retained.
Why using ground-based telescopes is so difficult
Imaging using ground-based telescopes is tricky because the telescope has to peer through Earth’s turbulent atmosphere where wind and temperature changes distort and blur the image (as shown on the left of the above image). Once in a while everything settles and a “lucky” sharp image is obtained (right). The research team kept all the sharpest exposures and created a mosaic of the whole disk of Jupiter.
“These images rival the view from space,” said Wong.
What’s going on in the ‘Great Red Spot?’
Dark spots in the Great Red Spot—the Solar System’s largest storm 22 degrees south of Jupiter’s equator that’s been raging since at least the year 1830—are revealed by these new images to be gaps in the cloud cover. Gemini’s images showed bright glowing infrared hotspots that could only be gaps.
“Similar features have been seen in the Great Red Spot before, but visible-light observation couldn’t distinguish between darker cloud material, and thinner cloud cover over Jupiter’s warm interior, so their nature remained a mystery,” said Glenn Orton of JPL and a member of the team.
Jupiter’s constant, gigantic storms
The giant planets has enormous storms compared to those on Earth, with thunderheads reaching 40 miles from base to top. That’s five times taller than those found on Earth. Jupiter also sees lightning flashes up to three times more energetic than Earth’s largest “superbolts.”
How sharp are Gemini’s images of Jupiter?
Gemini’s infrared “lucky imaging” observations achieved 300 miles/500 kilometers per pixel, which is an angular resolution down to 0.13 arc-seconds. “At this resolution, the telescope could resolve the two headlights of a car in Miami, seen from New York City,” said Andrew Stephens, the Gemini astronomer who led the observations.
The results were published in the April 2020 issue of The Astrophysical Journal Supplement Series.
On July 14, 2020, Jupiter will be at opposition—Earth will be directly between the Sun and the giant planet—so the latter will appear to be at its brightest of the entire Earth year. Get behind any small telescope and you’ll be able to see its distinctive cloud bands—and its Great Red Spot—for yourself. Even with binoculars you’ll easily see its four largest moons; Io, Europa, Ganymede, and Callisto.
Wishing you clear skies and wide eyes.
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Source: Forbes
