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Compare Webb's Images to Hubble

johnedchristensen.github.io

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Re: Compare Webb's Images to Hubble

#22
post #4

Here's a backyard telescope versus Webb: https://twitter.com/AJamesMcCarthy/status/154694183270093209... More comparisons on Twitter, some zoomed in: - https://twitter.com/Batsuto_/status/1546899241880240128 - https://twitter.com/Batsuto_/status/1546900387931766784 - https://twitter.com/JBWillcox/status/1546881033597075457 - https://twitter.com/jason4short/status/1546626672488632321 I'm not a physicist, so I've only…

The spikes are caused by diffraction of light around the struts supporting the secondary mirror. Hubble has 4 supports for the secondary mirror. JWST has 3 support for the secondary mirror, which because...physics (I don't know I'm not an optics guy)...manifests as 6 diffraction lines. https://en.wikipedia.org/wiki/Diffraction_spike EDIT: It may be caused by both the diffraction spikes from the supports struts and th…

Apparently the Diffraction spikes come from both the primary mirror shapes and the struts holding the secondary mirror. The primary mirrors of the JWST are hexagonal which would explain hexagonal looking effects. The three struts are apparently designed so that two of the struts match the hexagonal mirror angles at all times and are "hidden" inside. (The third strut apparently sometimes causes two much smaller "horizon" spikes for very, very bright objects.)

Hank Green on TikTok did a neat, quick demonstration in video form.

Re: Compare Webb's Images to Hubble

#24
> This makes the Hubble telescope even more impressive in my eyes. Built 50 years ago with presumably 60 year old tech.

> > Hubble telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency. Its intended launch was 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster. Hubble was finally launched in 1990.

I commented on this other thread: https://news.ycombinator.com/item?id=32074242

Re: Compare Webb's Images to Hubble

#26
Question for anyone who happens to be an expert: Is there any way to quantify how much better Webb is independently of the amount of time used to take the exposures? Like, could Hubble achieve the same quality of images as Webb if it was given 100x (or whatever) more time exposure?

I'm trying to understand how much the improvement is "speed of convergence" vs. "quality of asymptotic result". (Though... is that even a valid way of trying to understand things?)

Re: Compare Webb's Images to Hubble

#27

Now build a zoomable full-res version. Because I am spoiled and want the internet to do things for me.

ESA got your back:

quintet: https://esawebb.org/images/weic2208a/zoomable/

https://esawebb.org/images/weic2208b/zoomable/

carina: https://esawebb.org/images/weic2205a/zoomable/

https://esawebb.org/images/weic2205b/zoomable/

Southern ring https://esawebb.org/images/weic2207a/zoomable/

https://esawebb.org/images/weic2207b/zoomable/

https://esawebb.org/images/weic2207c/zoomable/

Deep field https://esawebb.org/images/weic2209a/zoomable/

https://esawebb.org/images/weic2209b/zoomable/

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