Share this page!

NASA Webb Telescope Profile picture
Twitter logo
Feb 11 • 4 tweets • 2 min read
Bonus image! When it’s time to focus, sometimes you need to take a good look at yourself.

This “selfie” taken by Webb of its primary mirror was not captured by an externally mounted engineering camera, but with a special lens within its NIRCam instrument. #UnfoldTheUniverse A black and white image of the primary mirror of the Webb Te
This special lens is meant for engineering, not science, and allows NIRCam to capture an “inward-looking” image of the primary mirror. This image helps us to check that the telescope is aligned with the science instruments. blogs.nasa.gov/webb/2022/02/1…
What you are seeing is the actual primary mirror of Webb as it observes its engineering target, a bright star. All the mirror segments are seeing starlight, but the bright segment is bright because, from NIRCam’s view, the segment is directly aligned with the star.
Over the next 3 months, we will be aligning each mirror segment individually so that all 18 reflections of this star are precisely overlayed until the telescope only sees a single, focused star. #ICYMI, check out this video ⤵️

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with NASA Webb Telescope

NASA Webb Telescope Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @NASAWebb

NASA Webb Telescope Profile picture
Feb 11
The 18 random dots featured in this video might not look like much, but they represent a big step forward in #NASAWebb’s 3-month mirror alignment process and its quest to #UnfoldTheUniverse: blogs.nasa.gov/webb/2022/02/1…

Let’s connect the dots with a thread ⬇️
⚫️ These dots confirm that Webb’s Near-Infrared Camera, or NIRCam, can collect light from celestial objects — and that starlight from the same star can be reflected from each of Webb’s 18 unaligned mirror segments back at Webb’s secondary mirror and then into NIRCam’s detectors.
⚫️ Our team first chose a bright, isolated star called HD 84406. Over ~25 hours, Webb was repointed to 156 positions around the star's predicted location, generating 1560 images with NIRCam’s 10 detectors. This is just the center of an image mosaic with over 2 billion pixels! The James Webb Space Telescope's initial alignment mosaic, s
Read 8 tweets
NASA Webb Telescope Profile picture
Jan 21
So…you’ve heard that the Webb telescope will be orbiting Lagrange point 2. But what even is that, anyway? And how do you orbit something that isn’t an object?

We’ve got you! Here’s a thread ⬇️
#UnfoldTheUniverse
First, the basics. Lagrange points refer to locations where the gravitational forces of 2 massive objects — such as the Sun and Earth — are in equilibrium. Webb will be located more specifically at Sun-Earth Lagrange point 2, or L2 for short.
Why send Webb to orbit L2?

😎 Shade: The Sun, Earth (and Moon) are always on one side. At L2, Webb’s sunshield can always face all of these heat & light sources to protect Webb’s optics & instruments, which have to stay super cold to detect faint heat signals in the universe.
Read 11 tweets
NASA Webb Telescope Profile picture
Jan 13
Yesterday we commanded all 132 motors on Webb’s primary & secondary mirrors to move them for the first time in space! #UnfoldTheUniverse

In today’s blog, @SpaceTelescope’s deputy telescope scientist Marshall Perrin takes us through a deep dive: blogs.nasa.gov/webb/2022/01/1…👇
🚀 The Ride to Space

Each of Webb’s mirror segments has 3 metal pegs on its back, which fit snugly into matching sockets in the telescope structure. During launch, the mirrors were tucked safe and sound.
Tiny Dancers 🩰

Over about 10 days, each mirror segment will move out by 12.5 mm (about half an inch) to get the pegs clear from the sockets. It may not sound like much, but these initial moves are actually the largest moves Webb’s mirror motors will ever make in space!
Read 5 tweets
NASA Webb Telescope Profile picture
Jan 10
❄️ Now that our deployments are complete, just like our telescope, we’re entering a period of cooldown. Our updates will be less frequent, but that doesn’t mean things have stopped happening: blogs.nasa.gov/webb/2022/01/1…

Thread ⬇️ Screen still of the James Webb Space Telescope's primary mir
First, what do we mean by “cooldown”? If you’ve been checking the temperatures of our “cold side” at webb.nasa.gov/whereiswebb, you can see we’re still a ways off from our operating temperatures of less than 50 Kelvin (about -370° F, or -223° C).

The deployment of our sunshield helped a lot with quickly lowering the temperatures on the cold side, but further cooling down will take place more slowly over time. The sunshield helps to passively cool Webb, meaning the optics get cold solely by being in the shade. 🌡
Read 8 tweets
NASA Webb Telescope Profile picture
Jan 8
We are GO for #NASAWebb’s final mirror wing deployment this morning! Here’s what you should expect:

🔲 Fire pins to release mirror wing
🔲 Unfold mirror
🔲 Latch the wing (2+ hours) ⏱
🔲 🥳🕺🏽🎉
🔲 #UnfoldTheUniverse! (5+ months) ✨
More: go.nasa.gov/3G8Bc1P The James Webb Space Telesc...
✅ Click! We just fired the last 4 of #NASAWebb's 178 release mechanisms, or pins — all of which had to work perfectly for this unfolding to take place. These 4 will release the restraints that held Webb's mirror wing safely in place during launch. #UnfoldTheUniverse
🚗 Folks, start your engines!

As the #NASAWebb team gets ready to deploy the second primary mirror wing from @SpaceTelescope, they just completed a small motor checkout movement, ensuring the wing is ready to go. #UnfoldTheUniverse
Read 11 tweets
NASA Webb Telescope Profile picture
Jan 6
We've been hearing you loud and clear: Why doesn't Webb have cameras for its journey to #UnfoldTheUniverse? It sounds like a no-brainer, but there's more to it than meets the lens. Thread ⬇️ Artist impression of the fully deployed James Webb Space Tel
1. Light 💡

Our gold-coated mirrors were photogenic on Earth, but the mirror side of Webb is pitch dark in space. Meanwhile, the other, Sun-facing side of Webb is so shiny that cameras there would have glare & contrast issues.
2. Power 🔌

We would have to run cables and power out to cameras on Webb, and the power balance on the cold side of Webb is especially delicate. More cables adds more of a threat of heat and vibration transfer through the wires, which could impact image quality.
Read 7 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Like this author's thread?

Get emails when @NASAWebb has new unrolls!

Check out other threads from @NASAWebb!

Read all threads by @NASAWebb

:(