牧夫天文招募翻译官

第一题：将本篇文章翻译成中文。

It can't get much better than this: an occultation of the brightest star the Moon ever crosses, visible across most of the U.S. on a Saturday evening, with the Moon barely first-quarter (46% sunlit), and the star's dark-side disappearance visible without optical aid.

Moreover, along a narrow path skirting the U.S.-Canadian border, passing the Toronto area and then the U.S. Northeast, a spectacular grazing occultation will occur that, at least in the populous eastern part of the path, will be nearly as good as last July's well-observed Aldebaran graze in the southern plains.

The graze provides another opportunity to detect the angular size of a star other than the Sun. But this time, the Moon will be brighter with the graze events occurring closer to the northern cusp, so binoculars are recommended to see the gradual and partial occultation events that will reveal the star's angular size.

The occultation will also be visible at night throughout Mexico, most of Central America, the western Caribbean Sea, and Bermuda. The occultation will occur in daylight in Hawai'i (disappearance at 3:33 p.m. HST in Honolulu).

The southern-limit graze will occur on the Moon's sunlit limb 6° inside the southern cusp, as seen from a narrow path crossing Costa Rica, Panama, and Colombia. A telescope is needed to see or record the star's reappearance even at night, because this will occur on the Moon's sunlit edge.

第二题：将以下2篇英语文章分别提炼成2则100字左右的中文简讯。

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An instrument onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) detected atomic oxygen in the atmosphere of Mars for the first time since the last observation 40 years ago. These atoms were found in the upper layers of the Martian atmosphere known as the mesosphere.

Atomic oxygen affects how other gases escape Mars and therefore has a significant impact on the planet’s atmosphere. Scientists detected only about half the amount of oxygen expected, which may be due to variations in the Martian atmosphere. Scientists will continue to use SOFIA to study these variations to help better understand the atmosphere of the Red Planet.

"Atomic oxygen in the Martian atmosphere is notoriously difficult to measure," said Pamela Marcum, SOFIA project scientist. "To observe the far-infrared wavelengths needed to detect atomic oxygen, researchers must be above the majority of Earth’s atmosphere and use highly sensitive instruments, in this case a spectrometer. SOFIA provides both capabilities."

The Viking and Mariner missions of the 1970s made the last measurements of atomic oxygen in the Martian atmosphere. These more recent observations were possible thanks to SOFIA’s airborne location, flying between 37,000-45,000 feet, above most of the infrared-blocking moisture in Earth’s atmosphere. The advanced detectors on one of the observatory’s instruments, the German Receiver for Astronomy at Terahertz Frequencies (GREAT), enabled astronomers to distinguish the oxygen in the Martian atmosphere from oxygen in Earth’s atmosphere. Researchers presented their findings in a paper published in the journal Astronomy and Astrophysics in 2015.

SOFIA is a Boeing 747SP jetliner modified to carry a 100-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center. NASA’s Ames Research Center in Moffett Field, California, manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is based at NASA’s Armstrong Flight Research Center's hangar 703 in Palmdale, California.

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Many galaxies are found to have an extremely bright core powered by a supermassive black hole. These cores make “active galaxies” some of the brightest objects in the Universe. They are thought to shine so brightly because hot material is glowing fiercely as it falls into the black hole, a process known as accretion. This brilliant light can vary hugely between different active galaxies, so astronomers classify them into several types based on the properties of the light they emit.

Some of these galaxies have been observed to change dramatically over the course of only 10 years; a blink of an eye in astronomical terms. However, the active galaxy in this new study, Markarian 1018 stands out by having changed type a second time, reverting back to its initial classification within the last five years. A handful of galaxies have been observed to make this full-cycle change, but never before has one been studied in such detail.