James Webb Space Telescope (JWST)

[Grendal]

 

[Grendal]

NASA to Discuss Progress as Webb Telescope’s Mirrors Align - NASA

NASA will hold a virtual media briefing at noon EDT Wednesday, March 16, to provide an update on the James Webb Space Telescope’s mirror alignment. The

www.nasa.gov

 

[Electroman]

Looks like they are ahead in terms of timelines. Just great

 

[Young]

NASA to Discuss Progress as Webb Telescope’s Mirrors Align - NASA

NASA will hold a virtual media briefing at noon EDT Wednesday, March 16, to provide an update on the James Webb Space Telescope’s mirror alignment. The

www.nasa.gov

NASA’s Webb Reaches Alignment Milestone, Optics Working Successfully - NASA

Lee esta nota de prensa en español aquí.

www.nasa.gov

First fully aligned image!

 

[Grendal]

 

[AudubonB]

The new photo (photos?) released 3/16 or 3/17 is touted as demonstrating the various lenses are aligning as per plan to create the sharp visual image desired.

I admit that artistically I see a beautiful picture of a star, but don’t those long rays emanating from it indicate asterism (I think I’m recalling the correct term) that demonstrates lenticular error, akin to coma?

Also: check out the near-twin star on the left-most side of the picture. It’s a six-pointed beauty, just the same as a child would draw! (errr…me, too).

Here’s a typical link to the photograph: New James Webb Space Telescope photo showcases single star in key mission milestone

 

[scaesare]

The new photo (photos?) released 3/16 or 3/17 is touted as demonstrating the various lenses are aligning as per plan to create the sharp visual image desired.

I admit that artistically I see a beautiful picture of a star, but don’t those long rays emanating from it indicate asterism (I think I’m recalling the correct term) that demonstrates lenticular error, akin to coma?

Also: check out the near-twin star on the left-most side of the picture. It’s a six-pointed beauty, just the same as a child would draw! (errr…me, too).

Here’s a typical link to the photograph: New James Webb Space Telescope photo showcases single star in key mission milestone

I wondered about the flare too.

 

[AudubonB]

I mourn for my crumbling knowledge of refractive errors and how to correct them but put another way, a prime reason for throwing telescopes out to space is to bypass just that flare that is caused by atmospheric disturbances.

 

[AudubonB]

Just had a thought: perhaps that alignment star’s output is too bright for sensors attempting to look at cross sections of flea hairs from 99 billion light years away. That the neighboring galaxies &c in the photo do not suffer such asterism might corroborate this?

 

[Young]

Just had a thought: perhaps that alignment star’s output is too bright for sensors attempting to look at cross sections of flea hairs from 99 billion light years away. That the neighboring galaxies &c in the photo do not suffer such asterism might corroborate this?

These spikes around bright objects are there due to the shape of finite size "aperture". When light pass by objects, part of it diffracts. Circular apertures create circular diffraction patterns overlayed to each bright points. In this case, dominant pattern is probably from the shape of the individual hexagonal primary mirrors.

 

[favo]

These spikes around bright objects are there due to the shape of finite size "aperture". When light pass by objects, part of it diffracts. Circular apertures create circular diffraction patterns overlayed to each bright points. In this case, dominant pattern is probably from the shape of the individual hexagonal primary mirrors.

Someone asked about it on the live stream, and that's basically what they said (I am not an optical engineer). They also mentioned the support struts for the secondary mirror as a contributing factor. It was also stated that they had achieved "diffraction-limited" focus, so can't really do any better due to physics.

 

[AudubonB]

Ah! Brings back memories, yes: circular apertures and circular diffusion patterns; SLR camera leafs create hexagons and hexagonal patterns. So that must be much of the answer…..it may be analogous but it seems to me not 100% identical here. The mirror is made of hexagons but that doesn’t mean the aperture also is.

 

[wart]

I read on another forum that the six lines are diffraction spikes. Caused not by the mirrors themselves but by the support struts for the secondary mirror. As @favo was saying.

 

[Electroman]

Also: check out the near-twin star on the left-most side of the picture. It’s a six-pointed beauty, just the same as a child would draw! (errr…me, too).

This is the picture and which star on the left most side are you referring to?

 

[AudubonB]

Go directly along the main star’s 0-axis - the minor line dead-horizontal - leftwards. Take a close-up look at the nigh-double that that line, extended, would pass through. See the “cut out” version of a six-pointed “star”? As Gus said, “It’s just like the ones on my bedroom ceiling!”.

I found two similar ones, not quite so sharp.

 

[ecarfan]

I love how multiple galaxies are visible in that photo. Imagine what the JWST will be able to see when it really gets to work! It could blow away the Hubble Deep Field view.

 

[ecarfan]

This headline startled me but the damage apparently was minimal and it should not impair the operation of the telescope.

James Webb Space Telescope struck by micrometeoroid

While it’s normal for spacecraft to experience impact events of this nature, NASA noted that this particular micrometeoroid, which hit the telescope between May 25 and May 27, was larger than any it had forecast when modeling such events prior to the mission’s launch in December 2021.

Analysis of the damage to the mirror segment is ongoing, but NASA said the early indications are that the telescope is continuing to perform “at a level that exceeds all mission requirements despite a marginally detectable effect in the data.”

Commenting on the strike, Paul Geithner, technical deputy project manager at NASA’s Goddard Space Flight Center, said: “We always knew that Webb would have to weather the space environment, which includes harsh ultraviolet light and charged particles from the sun, cosmic rays from exotic sources in the galaxy, and occasional strikes by micrometeoroids within our solar system. We designed and built Webb with performance margin — optical, thermal, electrical, mechanical — to ensure it can perform its ambitious science mission even after many years in space.”

 

[Ben W]

Was it Roadster-shaped?

While it’s normal for spacecraft to experience impact events of this nature, NASA noted that this particular micrometeoroid, which hit the telescope between May 25 and May 27, was larger than any it had forecast when modeling such events prior to the mission’s launch in December 2021.

 

[scaesare]

First image tonight! Then more tomorrow...

JWST First Image

 

[Grendal]