James Webb Space Telescope

[John in Santa Cruz]

the final orbit around L2 will be a 100,000 km circle, it will always be in direct sunlight to supply power to its solar cells, AND far enough away from the sun-earth such that the sun's radio emissions don't overwhelm the earth transmissions

btw, secondary mirror boom successfully deployed: https://blogs.nasa.gov/webb/

[Centex]

Originally Posted by John in Santa Cruz

the final orbit around L2 will be a 100,000 km circle, it will always be in direct sunlight to supply power to its solar cells ...

Ah, right you are, thanks for the reminder.

[Mike Lewis]

Given that the JWST will be gathering data in the infrared, not in the visible spectrum like Hubble, the public may be disappointed in the resulting images. I'm sure NASA's well-oiled PR machine has come up with a workaround, though.

[gbaglo]

Originally Posted by Mike Lewis

Given that the JWST will be gathering data in the infrared, not in the visible spectrum like Hubble, the public may be disappointed in the resulting images.

Apparently Hubble shoots black and white images which are converted to colour, so it shouldn't be a problem.

[marsman]

Wow it's so great to see everyone's enthusiasm for the JWST! I too am completely blown away at the ingenuity of its design. For that matter all of the missions that NASA and its partners have accomplished in the past 20 years are almost beyond belief; to name a few -

1. big bouncy spacecraft that land like giant basketballs (Spirit and Opportunity rovers)

2. Landed two SUV-sized nuclear powered rovers (Curiosity and Perseverance) on Mars using a floating sky-crane and then flying around a helicopter (who comes up with this stuff?)

3. The great Cassini mission that visited Jupiter and Saturn and some of their most interesting moons - flying through Europa's water geysers, landing on Titan, flying through Saturn's rings

4. the New Horizons mission that actually flew within a few thousand kms of Pluto's surface (my god, that thing is billions of miles away!!)

5. OSIRIS Rex which actually collected a chunk of asteroid

And the upcoming DART mission which is going to crash into an asteroid to move it enough to change the orbit of it's sister asteroid as a possible future planetary defense strategy!!

This agency is more fun and exciting to follow than any Hollywood Blockbuster movie and that's the TRUTH

[Mike Lewis]

Yeah, they've had a good run. I'd like to see orbiters around Uranus and Neptune in my lifetime but I don't think it's going to happen.

[Mike Lewis]

Originally Posted by gbaglo

Apparently Hubble shoots black and white images which are converted to colour, so it shouldn't be a problem.

That reminds me-- in the 1980s - early 90s I was a member of the Baltimore Astronomical Society. As the Space Telescope Science Institute is located in Baltimore, we would have speakers from STScI talk to us. One woman brought an imaging sensor like that used in Hubble. It was a slab of silicon about 4x8 inches.


I also got to know an STScI staff astronomer. I mentioned to him once that I'd read that they couldn't photograph the moon with Hubble because it was too bright. He said no-- the moon wasn't too bright; in fact they had come up with a "guide crater" catalog analogous to Hubble's guide star catalog used for deep space imaging. The problem was that the moon moved too fast in its orbit to track it correctly with Hubble. In fact, he said, it was a challenge to photograph the planets with Hubble's wide field / planetary camera because of their motion.

STScI is also running the JWST program.

[John in Santa Cruz]

Originally Posted by gbaglo

Apparently Hubble shoots black and white images which are converted to colour, so it shouldn't be a problem.

a lot of astrophotography even with visual light is done with multiple monochrome exposures through narrow band filters, then later combined in a computer to create a pseudocolor image.

[Great Eggstrications]

Originally Posted by marsman

I too am completely blown away at the ingenuity of its design.

Amen to that!

This You Tube video does a good job (IMHO) of going into some of the interesting design and construction details - for the aspiring geeks among us:

https://www.youtube.com/watch?v=aICaAEXDJQQ

Happily, they apparently didn't let Dometic help with the cyrocooler!

[marsman]

Congratulations to NASA, main sunshield is fully deployed and now the main mirror is unfolded!! GO NASA GO

[John in Santa Cruz]

yup, next 2 weeks are spent exercising and aligning the mirror segment actuators.

latest NASA JWST blog entry suggests updates going forward will be more like weekly instead of daily.
https://blogs.nasa.gov/webb/

[GeorgeB]

I LOVE the James Webb Project! Great to hear others are inspired! Before someone gets mad that this is not a RV post, I'm going to say, "I can't wait until they use those James Webb sun shields in the 5.0 Escape for a insulation barrier." "Those new improved NASA solar panels are going to look amazing on the Escape." Ha HA!

[Donna D.]

Originally Posted by GeorgeB

Before someone gets mad that this is not a RV post,.............

It's all good George. You posted it in Cyber Campfire

[GeorgeB]

Originally Posted by Donna D.

It's all good George. You posted it in Cyber Campfire

Oh, good. I am a newbie. lol

[Great Eggstrications]

Looking past the current state of world affairs, the following YouTube link may prove to be of interest to some:

https://www.youtube.com/watch?v=5MxH1sfJLBQ

I had wondered how they were going to be able to tweak the positions and contours of the separate mirrors to within the ridiculously exacting tolerances...

[Donna D.]

WOW! “Better than our most optimistic prediction” – first images from James Webb exceed all expectations

[Centex]

Originally Posted by Donna D.

WOW! “Better than our most optimistic prediction” – first images from James Webb exceed all expectations

Yep, it's great, and checking-in on the Webb Blog and NASA 'Webbsites' () linked previously in this thread is still and will likely remain a fun and informative pastime.

[Centex]

Another update (April 1, 2022) on the NASA Webb Blog describes continuing success relating to the deployment of Webb and making it ready for its long-term mission.

An ongoing process, but the reports to date are certainly an impressive testament to the almost incredible planning and execution by the many folks around the world involved in this amazing space telescope.

There's so much to look forward to in this project, it's great to have a good-news story of international cooperation to follow these days.

[WillyB]

Words never spoken in my profession.

"... cools to its cryogenic operating temperature ..."

Science is pretty amazing.

[John in Santa Cruz]

phew, I was curious, so I looked up some numbers of the JWST telescope.

the primary objective is 6.5m across, and is effectively f/20, which means it has a 135,000 mm focal length. the shorter wavelength elements of the NIRcam, each pixel is 0.031 arcseconds square. thats an incredibly tiny pixel size, when I use my 20" f/5 telescope here on the ground, about the smallest thing I can resolve is 1 arc seconds. double stars that are 2 arc seconds apart are hard to separate unless the seeing conditions are exceptionally good.