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Webb telescope is lightyears ahead of Hubble. A NASA Ames scientist explains why.

Original post made on Jul 14, 2022

The first image revealed from NASA's James Webb Space Telescope earlier this week isn't just the deepest and sharpest glimpse humans have of the distant universe so far. It's also a peek at 4.6 billion years into the past.

Read the full story here Web Link posted Thursday, July 14, 2022, 2:40 PM

Comments (2)

Posted by William Hitchens
a resident of Mountain View
on Jul 14, 2022 at 6:20 pm

William Hitchens is a registered user.

A nearly deadly embarrassment to NASA, the "huge" primary mirror of Hubble was both incorrectly ground and too also thin for its mounting assembly, no design changes were made to the complex assembly to compensate for them, the errors were not caught by OPTICALLY TESTING THE FINAL ASSEMBLY (an inconceivably ignorant engineering mistake), and NASA launched this bad primary mirror into space where it couldn't be replaced. Early images by Hubble were useless for its intended mission. After a lot of career- and pension-threatening embarrassing negative publicity, NASA management finally 'fessed up and said the Hubble optics were at fault (for deliberately vague unspecified reasons) and predictable & cowardly never took the blame for their gross screw-ups. NASA couldn't change the main mirror's defects, so they replaced several secondary replaceable optical modules in a brilliant 1993 rescue mission.

I knew the ex-Lockheed systems engineer and a near genius, who designed the most important optical module that needed to be replaced. Since NASA didn't even know (WHY!!!???) exactly what the errors were or how bad they were, he couldn't use standard fixed optics. He had to design a module using an adaptive optics secondary mirror to minimize, but not eliminate, Hubble's primary mirror's highly flawed vision of the Universe. This is probably one of the first successful uses of adaptive optics except maybe in classified military surveillance satellites. To be simple, adaptive optics in this case meant using a mirror consisting of many small segments, each of which could be manipulated independently under computer control to optimize the focus of the image coming out of the module. Adaptive optics has been incorporated in the James Webb satellites multiple mirrors, to a stunningly great effect.

He told me: "I did my very best, but Hubble would have been far better if the idiots had made and tested it right the first time." And he did damned well.


Posted by PST
a resident of South of Midtown
on Jul 15, 2022 at 11:02 am

PST is a registered user.

Sadly the telescope was named after a homophobic jerk who was instrumental in persecuting gay people within NASA, one of whom left to start the Mattachine Society. They need to change its name immediately and listen to the over 1000 scientists and academics who signed a petition to protest this horrific choice.


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