New camera may capture distant images without long lens

April 17, 2017

Houston, Apr 17: Scientists, including one of Indian origin, have developed a unique camera that can capture detailed images of distant objects without using a long lens, an advance that could lead to telescopes that are less bulky. The system known as SAVI – for “Synthetic Apertures for long-range, subdiffraction-limited Visible Imaging” – does not need a long lens to take a picture of a faraway object, researchers said.The prototype built by researchers reads a spot illuminated by a laser and captures the “speckle” pattern with a camera sensor.

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The prototype built by researchers reads a spot illuminated by a laser and captures the “speckle” pattern with a camera sensor.

Raw data from dozens of camera positions is fed to a computer programme that interprets it and constructs a high-resolution image.Researchers including those from Rice University in the US, built and tested the device that compares interference pat terns between multiple speckled images. Like the technique used to achieve the “Matrix” special effect, the images are taken from slightly different angles, but with one camera that is moved between shots instead of many fired in sequence. The prototype only works with coherent illumination sources such as lasers.

However, it is a step toward a SAVI camera array for use in visible light, researchers said. The speckles serve as reference beams and essentially replace one of the two beams used to create holograms, researchers said. When a laser illuminates a rough surface, the viewer sees grain-like speckles in the dot, as some of the returning light scattered from points on the surface has to go farther and throws the collective wave out of phase. The texture of a piece of paper – or even a fingerprint -is enough to cause the effect.

“Today, the technology can be applied only to coherent (laser) light,” said Ashok Veeraraghavan of Rice University.”That means you cannot apply these techniques to take pictures outdoors and improve resolution for sunlit images -as yet,” Veeraraghavan said.”With a traditional camera, the larger the physical size of the aperture, the better the resolution,” he said.

“If you want an aperture that is half a foot, you may need 30 glass surfaces to remove aberrations and create a focused spot.
This makes your lens very big and bulky,” he added. SAVI"s “synthetic aperture” sidesteps the problem by replacing a long lens with a computer programme the resolves the speckle data into an image, researchers said.

“You can capture interference patterns from a fair distance,” Veeraraghavan said. The research was published in the journal Science Advances.

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Agencies
July 2,2020

Paris, Jul 2: Several interacting exoplanets have already been spotted by satellites. But a new breakthrough has been achieved with, for the first time, the detection directly from the ground of an extrasolar system of this type.

An international collaboration including CNRS researchers has discovered an unusual planetary system, dubbed WASP-148, using the French instrument SOPHIE at the Observatoire de Haute-Provence (CNRS/Aix-Marseille Universite).

The scientists analysed the star's motion and concluded that it hosted two planets, WASP-148b and WASP-148c. The observations showed that the two planets were strongly interacting, which was confirmed from other data.

Whereas the first planet, WASP-148b, orbits its star in nearly nine days, the second one, WASP-148c, takes four times longer. This ratio between the orbital periods implies that the WASP-148 system is close to resonance, meaning that there is enhanced gravitational interaction between the two planets. And it turns out that the astronomers did indeed detect variations in the orbital periods of the planets.

While a single planet, uninfluenced by a second one, would move with a constant period, WASP-148b and WASP-148c undergo acceleration and deceleration that provides evidence of their interaction.

The study will shortly be published in the journal Astronomy & Astrophysics.

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Agencies
February 29,2020

Ahmedabad, Feb 29: The presence of two feral pigeons onboard a GoAir flight at the airport in Ahmedabad in Gujarat created a flutter among the amused passengers, even though the avian surprise did not lead to any untoward incident or delay in the flight.

The incident took place on Friday when the passengers were boarding the Ahmedabad-Jaipur flight.

"Two pigeons had found their way inside the flight G8 702 while the passengers were boarding," an airline statement said on Saturday.

"The crew immediately shooed away the birds. The flight took off at its scheduled time at 5 p.m.," it added.

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News Network
February 21,2020

London, Feb 21: Scientists have discovered a new species of land snail, and have named it Craspedotropis Greta Thunberg in honour of the Swedish activist Greta Thunberg for her efforts to raise awareness about climate change.

According to the study, published in the Biodiversity Data Journal, the newly discovered species belongs to the so-called caenogastropods -- a group of land snails known to be sensitive to drought, temperature extremes, and forest degradation.

The scientists, including evolutionary ecologist Menno Schilthuizen from Naturalis Biodiversity Center in the Netherlands, said the snails were found very close to the research field station at Kuala Belalong Field Studies Centre in Brunei.

They added that the snails were discovered at the foot of a steep hill-slope, next to a river bank, foraging at night on the green leaves of understorey plants.

The effort aided by amateur scientist J.P. Lim, who found the first individual of the snail said, "Naming this snail after Greta Thunberg is our way of acknowledging that her generation will be responsible for fixing problems that they did not create."

"And it's a promise that people from all generations will join her to help," Lim said.

The researchers said they approached Thunberg who said that she would be "delighted" to have this species named after her.

The study work including, fieldwork, morphological study, and classification of identified specimen was carried out in a field centre with basic equipment and no internet access, the scientists said.

According to the study, the work was done by untrained ‘citizen scientists’ guided by experts, on a 10-day taxon expedition.

"While we are aware that this way of working has its limitations in terms of the quality of the output (for example, we were unable to perform dissections or to do extensive literature searches), the benefits include rapid species discovery and on-site processing of materials," the researchers wrote in the study.

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