Spiny Norman said:
Somehow, someway, our night sky is changing.
And we don’t know why.
Pop culture has us thinking the sky is eternally permanent, like our pets when we were kids (why did you have to die ringo??) After all, we have used the stars as interstellar lighthouses to guide our ships in centuries past and we’ve made a universe (pun intended) of heroes and villains from patterns in the sky for much longer. But the truth is, we can mythologise the ancient Greek version of The Avengers in the sky, but we have watched with naked eyes and missing the minute details.
Question: what if we haven’t watched closely enough?
Alright we get it, we can’t all stare art the sky watching every star like an astronomical creche.
Fortunately, a group of astronomers has devised a way to compare 70-year-old surveys with snaps of today’s sky. So please, come inside and stop monitoring the stars now. The researchers used software to analyse the 600 million light signatures above us and compared them to skies of the past using data from the US Naval Observatory (USNO) over a period of decades starting in 1949, with observations by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) between 2010 and 2014.
The results were cross referenced yet again with other datasets to isolate the most promising anomalies, initially resulting in about 150,000 potential “missing” stars.
Finally, the team filtered through the remaining 24,000 cases one-at-a-time to define which remained a mystery and which could be attributed to errors such as camera malfunctions. And now, the Vanishing and Appearing Sources during a Century of Observations (VASCO) Project has announced their imminent findings after years of laborious work, revealing at least 100 stars of decades past have gone AWOL.
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> a group of astronomers has devised a way to compare 70-year-old surveys with snaps of today’s sky. So please, come inside and stop monitoring the stars now. The researchers used software to analyse the 600 million light signatures above us and compared them to skies of the past using data from the US Naval Observatory (USNO) over a period of decades starting in 1949, with observations by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) between 2010 and 2014.
That is not easy. The USNO catalogue is the largest of the old pre-Hubble telescopes catalogues. It was used in devising the set of stars that Hubble could be oriented on. But I know virtually nothing about the USNO work, it was originally classified of course. I vaguely remember that two not very large telescopes were used.
> The results were cross referenced yet again with other datasets to isolate the most promising anomalies, initially resulting in about 150,000 potential “missing” stars.
Other datasets being? Probably referring to the Palomar-Oschin sky survey. Yes, that would be it. “The First Palomar Sky Survey (POSS I) was carried out in the 1950’s using the 48-inch Oschin Schmidt telescope at Mount Palomar in southern California.”
> Finally, the team filtered through the remaining 24,000 cases one-at-a-time to define which remained a mystery and which could be attributed to errors such as camera malfunctions. And now, the Vanishing and Appearing Sources during a Century of Observations (VASCO) Project has announced their imminent findings after years of laborious work, revealing at least 100 stars of decades past have gone AWOL.
“At least” 100.
A note here for exophiles. Cross referencing USNO with ‘POSS I’ will already eliminate from consideration all interstellar spacecraft. So this 100 will not contain any interstellar spacecraft. There could still be many hundreds of thousands of interstellar spacecraft on film that we haven’t identified.
It will also have eliminated alien laser communications from the dataset, along with novas, supernovas, helium flashes, asteroids, and fast-moving stars.
Not eliminated will be fading planetary nebulas. With perhaps a few long period variables and cataclysmic variables.