James Webb Telescope

Red = Feb 11
Black = Feb 6

Frame and mirror
Primary Mirror -223 (50K) -218°C (55K)
Instrument Radiator -222 (51K) -215°C (58K)
Fine Steering Motor -229 (44K) -220°C (53K)

Instruments
MIRI -139 (134K) -129°C (144K)
NIRcam -209 (64K) -186°C (88K)
NIRSpec -201 (72K) -175°C (98k)
FGS/NIRISS -196 (78K) -175°C (98K)

The frame and mirror elements seem to be dropping at about one to two degrees per day. The instruments a bit quicker, about two to three degrees per day, but I expect that rate to slow as the temperatures get closer to absolute zero. MIRI is lagging a bit, and it has a long way to go.
 
Trebuchet said:
I'm somewhat boggled as to how they identify each of the 18 spots to a particular mirror.
Click to expand...

My guess is that they start out with an intentional significant mis-alignment which they have already estimated. If the error from where they expect it to be is smaller than the offset from the intentional misalignment, then the spots will all be easy to identify. They probably also move each mirror one at a time to verify that the expected spot moves, and also moves by the expected amount.
 
A couple of changes have been made to the "Where is Web" page

https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric

They have added a key for each stage of the mirror setup process

Step 1: Segment ID
Step 2: Segment Align
Step 3: Image Stacking
Step 4: Coarse Phasing
Step 5: Fine Phasing
Step 6: Telescope alignment
Step 7: Final Correction

A moving hexagonal box with a number inside (currently 1) shows which step is currently being undertaken.
 
Looks like the time scale is now indicating weeks rather than days.

Is the MIRI temperature where it's supposed to be at this point? Seems to be a lot warmer than the other instruments. But maybe there's a reason for that?
 
The timescale at launch was six months to first science. So another four months. Given how well everything's gone they might improve on that, but AIUI it's mostly a case of just waiting for it to cool.
 
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