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Vera C. Rubin Observatory first images

rubinobservatory.org

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Re: Vera C. Rubin Observatory first images

#11

Post by avmich »

NitpickLawyer wrote: post #3

So stoked for this observatory to go online! One cool uses it'll excel at is taking "deltas" between images and detect moving stuff. Close asteroids is one obvious goal, but I'm more interested in the next Oumuamua / Borisov like objects that come in from interstellar space. It would be amazing to get early warnings about those, and be able to study them with other powerful telescopes we have now.

> So stoked for this observatory to go online!

Second this, but other areas are of great interest too. Kuiper Belt discoveries and surveys FTW!

Re: Vera C. Rubin Observatory first images

#14

Post by IAmBroom »

NitpickLawyer wrote: post #5
jasonthorsness wrote: post #4

Why are there lens-flare-like artifacts around some of the bright objects?

Those are diffraction spikes, caused by how the light interacts with the support structure holding the secondary mirror. Each telescope has different patterns, hubble, jwst, etc. I think they only happen for stars, and not for galaxies (an easy way to know which is which), but I might be wrong on that (there's a possibility for faint stars not to have them IIRC).

No, they happen for absolutely every externally-generated pixel of light (that is, not for shot noise, or firelflies that happen to fly between the mirrors). Where objects subtend more than one pixel, each pixel will generate it's own diffraction patterns, and the superposition of all are present in the final image. Of course, each diffraction pattern is offset from the next, so they mostly just broaden (smear out), not intensify.

However, the brightness of the diffraction effects is much lower than the light of the focused image itself. Where the image is itself dim, the diffraction effects might not add up to anything noticeable. Where the image supersaturates the detector (as can happen with a 1-pixel-wide star), the "much lower" fraction of that intensity can still be annoyingly visible.

Re: Vera C. Rubin Observatory first images

#15

Post by japhyr »

-warren wrote: post #13

Counter-rotating spiral galaxies. Super neat! https://skyviewer.app/embed?target=186.66721+8.89072&fov=0.2...

That is interesting!

They look like they're roughly in the same plane. Is it safe to assume they're roughly in the same plane, or could they be really distant along the line of sight? The similarity in size makes me think they are, but I don't have any reason to be confident in that judgment.

Re: Vera C. Rubin Observatory first images

#18

Post by cogman10 »

dekhn wrote: post #8

I really like the Rubin because I think a lot of people focus too much on "deep" seeing (IE, looking at individual or several objects with very high magnification only once). The Rubin does much more "wide" seeing and this actually produces a ton of useful data- basically, enough data to collect reliable statistics about things. This helps refine cosmological models in ways that smaller individual observations cannot…

Deep is still interesting in understanding the origins of the universe. Rubin seems highly practical on the flip side. It'll be a super helpful tool in predicting asteroid impacts.

Re: Vera C. Rubin Observatory first images

#19

Post by petee »

NitpickLawyer wrote: post #5
jasonthorsness wrote: post #4

Why are there lens-flare-like artifacts around some of the bright objects?

Those are diffraction spikes, caused by how the light interacts with the support structure holding the secondary mirror. Each telescope has different patterns, hubble, jwst, etc. I think they only happen for stars, and not for galaxies (an easy way to know which is which), but I might be wrong on that (there's a possibility for faint stars not to have them IIRC).

The same effect is used for Bahtinov focusing masks. From what i know, all light will bend around the structures, but stars are bright and focused enough to see; in theory galaxies would too
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