<p>The exact date is still quite uncertain, because even though the telescope is now fully deployed, there are many small steps to go through — aligning the mirror segments, checking the optics, and calibrating the instruments — which are impossible to schedule exactly. But <a href="https://planet4589.org/space/misc/webb/time.html" rel="noreferrer">the timeline you link to</a> seems about right, meaning that we should see first light around the end of June.</p>
<p>STScI and NASA are planning to publish some &quot;Early Release Observations&quot; (ERO) for promotion right after commissioning, which are basically some pretty pictures (and maybe even a spectrum). These shouldn't be confused with their <a href="https://www.stsci.edu/jwst/science-execution/approved-ers-programs" rel="noreferrer">Early Release Science</a> (ERS) programs, which is &quot;real&quot; science, meant to showcase JWST's potential in terms of both targets and instruments). They will probably keep the ERO secret until the very last moment.</p>

CC BY-SA 4.0
2022-01-12T13:23:03.773Z
2022-01-12T13:23:03.773Z
pela
<p>Is there an <em>official</em> estimate when the <a href="https://en.wikipedia.org/wiki/First_light_(astronomy)" rel="noreferrer">first light</a> of the James Webb Space Telescope happens? I keep following the press releases from ESA and NASA, but I cannot recall that I saw any on that topic.</p>
<h3>References</h3>
<ul>
<li><a href="https://en.wikipedia.org/wiki/Timeline_of_the_James_Webb_Space_Telescope" rel="noreferrer">Timeline from Wikipedia</a></li>
<li><a href="https://planet4589.org/space/misc/webb/time.html" rel="noreferrer">Detailed timeline from planet4589.org</a></li>
</ul>

<james-webb-space-telescope>
When is JWST's first light?
B--rian
# When is JWST's first light?

(Asked by: username_0 on 2022-01-12)

Is there an *official* estimate when the [first light](https://en.wikipedia.org/wiki/First_light_(astronomy)) of the James Webb Space Telescope happens? I keep following the press releases from ESA and NASA, but I cannot recall that I saw any on that topic.

### References

* [Timeline from Wikipedia](https://en.wikipedia.org/wiki/Timeline_of_the_James_Webb_Space_Telescope)
* [Detailed timeline from planet4589.org](https://planet4589.org/space/misc/webb/time.html)

**Tags:** james-webb-space-telescope


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## 1 answers

### Answer by username_1 on 2022-01-12. Score: 8 | Accepted answer

The exact date is still quite uncertain, because even though the telescope is now fully deployed, there are many small steps to go through — aligning the mirror segments, checking the optics, and calibrating the instruments — which are impossible to schedule exactly. But [the timeline you link to](https://planet4589.org/space/misc/webb/time.html) seems about right, meaning that we should see first light around the end of June.

STScI and NASA are planning to publish some "Early Release Observations" (ERO) for promotion right after commissioning, which are basically some pretty pictures (and maybe even a spectrum). These shouldn't be confused with their [Early Release Science](https://www.stsci.edu/jwst/science-execution/approved-ers-programs) (ERS) programs, which is "real" science, meant to showcase JWST's potential in terms of both targets and instruments). They will probably keep the ERO secret until the very last moment.


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