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September 30, 2019

World's largest optical lens — 5.1 feet wide, it took 5 years to make

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From PetaPixel:

When you're building the world's largest digital camera, to power one of the world's most impressive telescopes, you're going to need to manufacture one of the world’s most incredible lenses.

That's how this massive, 5.1-foot-wide optic — the largest high-performance optical lens ever made — came to be.

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Th 3.2-gigapixel camera being built for the Large Synoptic Survey Telescope (LSST) was thought up over a decade ago.

But after getting the green light in 2011, and securing funding in 2015, it was off to the races as engineers and scientists began to turn this idea into a functioning reality.

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The camera features the largest CCD image sensor mosaic in the world, combining 189 individual sensors into a single 3.2-gigapixel imaging area that — once it's operational and perched atop Cherro Pachon mountain in Chile — will snap a 15-second exposure of the night sky every 20 seconds or so.

This will enable the telescope to capture the entire visible southern sky every few nights.

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But a sensor is nothing without some optics, and in the case of the LSST, that includes three massive mirrors and two lens elements: the 5.1-foot wide L1 lens element we're talking about today, and a "smaller" companion lens element that's "only" 3.9 feet wide.

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According to a press release published by the Lawrence Livermore National Laboratory (LLNL), the primary lens is "believed to be the world's largest high-performance optical lens ever fabricated."

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The two lenses were made by Colorado-based Ball Aerospace and its subcontractor, Tucson-based Arizona Optical Systems, over the course of five years, mounted together in a carbon fiber structure, and then shipped by truck from Tucson to the SLAC National Accelerator Laboratory in Menlo Park, California, where there was a bit of a celebration, some fist bumps, and a bunch of photographs taken upon the lens' safe arrival.

September 30, 2019 at 04:01 PM | Permalink | Comments (2)

Mathematicians' Blackboards

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[via the New York Times]

September 30, 2019 at 02:01 PM | Permalink | Comments (0)

It must be something in the water: Microplastic particles in bottled water

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From the CBC:

Researchers tested 259 bottles of water purchased in nine countries (U.S., Kenya, China, Brazil, India, Indonesia, Lebanon, Mexico, and Thailand; none were bought in Canada).

Though many brands are sold internationally, the water source, manufacturing, and bottling process for the same brand can differ by country.

The 11 brands tested include the world's dominant players — Nestle Pure Life, Aquafina, Dasani, Evian, San Pellegrino, and Gerolsteiner — as well as major national brands across Asia, Africa, Europe and the Americas.

Researchers found 93% of all bottles tested contained some sort of microplastic, including polypropylene, polystyrene, nylon, and polyethylene terephthalate (PET).

September 30, 2019 at 12:01 PM | Permalink | Comments (2)

Windy.com

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Wonderful weather website with beautiful graphics

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showing dozens of individual variables.

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Fair warning: there goes the day.

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[via reader Scott — more like this, please]

September 30, 2019 at 10:01 AM | Permalink | Comments (1)

Silicone Vase

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Features and Details:

• 5.9" x 5.9"

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• White silicone

• Clings to any smooth surface

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• Water is totally contained, so vase can be moved without spilling

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$6.95 (flowers not included).

September 30, 2019 at 08:01 AM | Permalink | Comments (0)

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