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Comment by rodiger | Hacker News Reader

Does anyone know offhand when we should receive the first images?

Of some interest, this is the proposed imaging breakdown by time:

   2.0 % observation calibration
   4.9 % instrument calibration
   7.9 % solar system (comets, asteroids, kuiper belt objects, etc)
  16.1 % exoplanets
  17.2 % nearby galaxies
  20.4 % galactic (debris disks, etc)
  31.5 % distant galaxies and cosmology

There's a whole huge breakdown of what instrumentation calibration entails: https://www.stsci.edu/jwst/about-jwst/history/science-operat...

This doc was drafted in 2012, and so this might've already changed or will be: https://www.stsci.edu/jwst/about/history/science-operations-...

About six months.

https://webbtelescope.org/quick-facts/mission-launch-quick-f...

> After reaching its orbit, Webb undergoes science and calibration testing. Then, regular science operations and images will begin to arrive, approximately six months after launch. However, it is normal to also take a series of "first light" images that may arrive slightly earlier.

It will take about a month for it to get out to the Sun-Earth L2 point which is 1.5M km (0.01 AU) from the Earth. For comparison, the Moon is 384k km away. The telescope will be 4x further away from the Earth than the Moon is.

We'll probably get the calibration images before the six months from now when regular science missions start if they go according to plan as it's great press. Also there's a chance that there's a delay on the science mission images to allow for academic publishing.

(and too late for an edit) that 1.5M km thing is moderately important when it comes to communication with the JWST.

The frequencies that can be used for communicating with a satellite or space probe are governed by how far away it is. The cut off for this is 2.0M km.

https://en.wikipedia.org/wiki/Deep_space_bands

And so, the JWST is still considered near earth and can't use the deep space bands.

https://deepspace.jpl.nasa.gov/dsndocs/810-005/201/201C.pdf

why is the exact frequency used important? what's different about near space bands versus deep space? they look arbitrary to my idiot eyes.

(I'm asking why the band used is significant in any way)

It's not a technical restriction, it's a regulatory one. Like how parts of the UHF spectrum are allocated to TV and parts to radio. They don't want near earth communication going on in the deep space band because it will swamp the weaker signal.

right but the bands are not far apart, and the comment I originally replied to seemed to imply that there was significance that it was in the near space category rather than deep space. like it enabled something or was important in some unmentioned way. it was the whole (unspoken) point of the comment and I'm not "in the know" enough to already know the unspoken part. I'm asking what the unspoken part is.

According to the wiki link above, the bands are similarly sized and adjacent, so this wouldn't have much to do with "physics". Perhaps the "near" bands are just more congested?

Many other posters have said 6 months, but it will likely be much earlier to get the first images.

6 Months is the time frame for regular science operations. It is likely NASA will share some images well before that from the calibration phase as part of mission PR.

As regular joe's on the internet we are only interested in those PR images, regular science operations are more important for astronomers applying for time on the telescope.

Beyond those initial PR images, we can perhaps expect some PR worthy research papers (i.e. kind of papers that will get posted here) maybe a year from now, given the first projects will get access 6 months from now.

~6 months.

https://webbtelescope.org/quick-facts/mission-launch-quick-f...

It would be 180 to 210 days from launch. There is a lot of calibration work for the mirrors along with cooling the telescope down.

Six months if I recall correctly

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