oce 🐆

I try to contribute to things getting better, with sourced information, OC and polite rational skepticism.
Disagreeing with a point ≠ supporting the opposite side, I support rationality.
Let’s discuss to make things better sustainably.
Always happy to question our beliefs.

  • 8 Posts
  • 452 Comments
Joined 2 years ago
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Cake day: July 7th, 2023

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  • I was surprised so I did the computation just to resolve the disk of Betelgeuse at 550 nm, and I found a telescope of 2.8 m, that’s definitely already doable. We already have 8 m in one piece and 10 m segmented, JWST is 6.5 m segmented. The ELT is planned to be 39 m for 2028. So this star is closer and bigger than I thought.

    And these are the images we have from one of the top imaging instrument SPHERE on the VLT in 2019. It’s precise enough to show the change of shape due to its variable star type.


  • It would be the size of the telescope’s diffraction artifacts probably. Meaning the shape you see on the picture is not related to the size of the star but only to the physical limits of the optical instrument. This diffraction pattern is proportional to the color your looking at and inversely proportional to the size of the telescope primary mirror. The bigger the telescope primary mirror, the smaller the diffraction pattern and the more chance you have that this artifact will not completely hide the object you are looking at. I didn’t do the math, but I guess to image the actual disk of Betelgeuse, the size of the telescope you need is probably still science fiction, even with interferometry.




  • The first step toward meaningful change begins with us. We must abandon our craving for glossy (and therefore glassy) devices, and instead embrace hardware that may not be as immediately pleasing to the eye (as it is the case with e.g. Fairphones or the PinePhone), but is built to be slightly more durable, somewhat repairable, and capable of outlasting even today’s limited commitments to software updates.

    Fairphone and PinePhone being only mentioned anecdotally for being too pretty, and I guess not as sturdy as the author wants, is quite weird for an article about reducing fragility and improving repairability.



  • I don’t think you can rely on volunteer labor and donations to keep things running indefinitely.

    Doesn’t that imply that it will not work on the long term?
    Or you think groups of volunteer will form up and maintain an instance for a while and then go down, and another group will pick up?
    I’m afraid we may run out of people able to do that after they all get burned out like ee’s.








  • Rich countries have highly developed sports infrastructures that allow better detection of talents and training the talents in the best possible conditions. That is probably already enough to explain the difference in results. No need to look for some drug conspiracy. If your city doesn’t have the money to build a swimming pool, you’ll never have swimming champions from there.