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  4. i nerd sniped myself tonight and i imagine the NSA operative who is assigned to me is very confused by the increasingly erratic and frustrated google searches for HOW DO I CALCULATE THE MOON WHERE IS THE MOON

i nerd sniped myself tonight and i imagine the NSA operative who is assigned to me is very confused by the increasingly erratic and frustrated google searches for HOW DO I CALCULATE THE MOON WHERE IS THE MOON

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  • Jon Valdésundefined Jon Valdés

    @aeva @dotstdy Yup! I was using trig to calculate screen positions for the stars. And as the skydome rotates, when the sin/cos of some stars happened to cross those bright lines you're seeing, they'd first slow down, and then jump over a very specific line in the sky. Was great 🙄

    aevaundefined Questo utente è esterno a questo forum
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    aeva
    scritto su ultima modifica di
    #23

    @jon_valdes @dotstdy 😧

    1 Risposta Ultima Risposta
    • Josh Simmonsundefined Josh Simmons

      @aeva @jon_valdes generally cpu trig is not so bad, but does vary between platforms if you're just calling the c stdlib functions (but we're talking differences of 1 ulp or so). so yes, absolutely you can get a warmer fuller soundstage by switching to a different sin.

      aevaundefined Questo utente è esterno a questo forum
      aevaundefined Questo utente è esterno a questo forum
      aeva
      scritto su ultima modifica di
      #24

      @dotstdy @jon_valdes maybe I'll call the expensive exact soft sin oscillator "gold plated sin" 🤔

      demofoxundefined 1 Risposta Ultima Risposta
      • aevaundefined aeva

        @dotstdy @jon_valdes maybe I'll call the expensive exact soft sin oscillator "gold plated sin" 🤔

        demofoxundefined Questo utente è esterno a questo forum
        demofoxundefined Questo utente è esterno a questo forum
        demofox
        scritto su ultima modifica di
        #25

        @aeva @dotstdy @jon_valdes start a new genre "deca-dance"

        aevaundefined 1 Risposta Ultima Risposta
        • demofoxundefined demofox

          @aeva @dotstdy @jon_valdes start a new genre "deca-dance"

          aevaundefined Questo utente è esterno a questo forum
          aevaundefined Questo utente è esterno a questo forum
          aeva
          scritto su ultima modifica di
          #26

          @demofox @dotstdy @jon_valdes well so far I can't tell the difference by ear between the soft sin and the double precision sin that clang gives me

          aevaundefined 1 Risposta Ultima Risposta
          • aevaundefined aeva

            @demofox @dotstdy @jon_valdes well so far I can't tell the difference by ear between the soft sin and the double precision sin that clang gives me

            aevaundefined Questo utente è esterno a questo forum
            aevaundefined Questo utente è esterno a questo forum
            aeva
            scritto su ultima modifica di
            #27

            @demofox @dotstdy @jon_valdes assuming I didn't screw anything up adapting Jon's shader toy, the 30 iteration soft sin also has the surprising property of being able to clip out of the expected -1.0 to 1.0 output range https://github.com/Aeva/mollytime/blob/af58e9237903856b6193a116ae6408038dc47d4a/src/patch.cpp#L319

            Tom Forsythundefined 1 Risposta Ultima Risposta
            • aevaundefined aeva

              @demofox @dotstdy @jon_valdes assuming I didn't screw anything up adapting Jon's shader toy, the 30 iteration soft sin also has the surprising property of being able to clip out of the expected -1.0 to 1.0 output range https://github.com/Aeva/mollytime/blob/af58e9237903856b6193a116ae6408038dc47d4a/src/patch.cpp#L319

              Tom Forsythundefined Questo utente è esterno a questo forum
              Tom Forsythundefined Questo utente è esterno a questo forum
              Tom Forsyth
              scritto su ultima modifica di
              #28

              @aeva @demofox @dotstdy @jon_valdes There's lots of versions of CPU sin/cos as well. The fastest is basically identical to the GPU one - about 12 bits of precision, IIRC. Then they do iteration internally if you want higher precision. There's no magic - everything costs!

              As you noticed, sometimes it's better not to call sin-vs-cos, because you're not guaranteed to get magnitude 1.0. In those cases it's better to get sin and derive the other by doing sqrt(1-sin^2).

              Tom Forsythundefined 1 Risposta Ultima Risposta
              • Tom Forsythundefined Tom Forsyth

                @aeva @demofox @dotstdy @jon_valdes There's lots of versions of CPU sin/cos as well. The fastest is basically identical to the GPU one - about 12 bits of precision, IIRC. Then they do iteration internally if you want higher precision. There's no magic - everything costs!

                As you noticed, sometimes it's better not to call sin-vs-cos, because you're not guaranteed to get magnitude 1.0. In those cases it's better to get sin and derive the other by doing sqrt(1-sin^2).

                Tom Forsythundefined Questo utente è esterno a questo forum
                Tom Forsythundefined Questo utente è esterno a questo forum
                Tom Forsyth
                scritto su ultima modifica di
                #29

                @aeva @demofox @dotstdy @jon_valdes Also, if you care about precision at all, do range reduction yourself beforehand. Otherwise you have no idea how it's being done internally.

                aevaundefined 1 Risposta Ultima Risposta
                • Tom Forsythundefined Tom Forsyth

                  @aeva @demofox @dotstdy @jon_valdes Also, if you care about precision at all, do range reduction yourself beforehand. Otherwise you have no idea how it's being done internally.

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                  aevaundefined Questo utente è esterno a questo forum
                  aeva
                  scritto su ultima modifica di
                  #30

                  @TomF @demofox @dotstdy @jon_valdes I already do the range reduction. I learned that the hard way once upon a time XD

                  1 Risposta Ultima Risposta
                  • aevaundefined aeva

                    wikipedia: even the ancient babylonians knew how to use math to figure out what the moon is up to

                    me: great how do i do that

                    wikipedia: 😏

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                    aevaundefined Questo utente è esterno a questo forum
                    aeva
                    scritto su ultima modifica di
                    #31

                    today's extremely basic astronomy question that i'm finding surprisingly difficult to find an answer to: are geographic coordinates and equatorial coordinates the same coordinate system except one is for looking up and the other is for looking down, or is there some essential conversion step needed to correlate them?

                    https://en.wikipedia.org/wiki/Geographic_coordinate_system

                    https://en.wikipedia.org/wiki/Equatorial_coordinate_system

                    aevaundefined 1 Risposta Ultima Risposta
                    • aevaundefined aeva

                      today's extremely basic astronomy question that i'm finding surprisingly difficult to find an answer to: are geographic coordinates and equatorial coordinates the same coordinate system except one is for looking up and the other is for looking down, or is there some essential conversion step needed to correlate them?

                      https://en.wikipedia.org/wiki/Geographic_coordinate_system

                      https://en.wikipedia.org/wiki/Equatorial_coordinate_system

                      aevaundefined Questo utente è esterno a questo forum
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                      aeva
                      scritto su ultima modifica di
                      #32

                      i feel like i'm so close to getting this working. i found a simple implementation of ELP2000-85 that gives the approximate ecliptic coordinates and distance of the moon for a given julian century, i found math for translating between ecliptic and equatorial coordinates, and the math for working with the julian calendar looks easy enough, so i just need to figure out the missing conversions and decide on an internal time keeping standard

                      aevaundefined 1 Risposta Ultima Risposta
                      • aevaundefined aeva

                        i feel like i'm so close to getting this working. i found a simple implementation of ELP2000-85 that gives the approximate ecliptic coordinates and distance of the moon for a given julian century, i found math for translating between ecliptic and equatorial coordinates, and the math for working with the julian calendar looks easy enough, so i just need to figure out the missing conversions and decide on an internal time keeping standard

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                        aevaundefined Questo utente è esterno a questo forum
                        aeva
                        scritto su ultima modifica di
                        #33

                        i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first

                        rfundefined SnoopJundefined aevaundefined 3 Risposte Ultima Risposta
                        • aevaundefined aeva

                          i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first

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                          rf
                          scritto su ultima modifica di
                          #34

                          @aeva On cosmology sequence breaks: Terence Tao noted that an ancient Greek heliocentrist got his arguments shot down because others said, hey, if the earth moves so much yet the stars seem to stay still, the universe would have to be *thousands* of times bigger than anyone figures it is. And how would you know, back then, it was way *more* than thousands of times bigger?

                          https://www.youtube.com/watch?v=YdOXS_9_P4U

                          aevaundefined 1 Risposta Ultima Risposta
                          • aevaundefined aeva

                            i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first

                            SnoopJundefined Questo utente è esterno a questo forum
                            SnoopJundefined Questo utente è esterno a questo forum
                            SnoopJ
                            scritto su ultima modifica di
                            #35

                            @aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did

                            divine geometry is a helluva drug

                            SnoopJundefined aevaundefined 2 Risposte Ultima Risposta
                            • rfundefined rf

                              @aeva On cosmology sequence breaks: Terence Tao noted that an ancient Greek heliocentrist got his arguments shot down because others said, hey, if the earth moves so much yet the stars seem to stay still, the universe would have to be *thousands* of times bigger than anyone figures it is. And how would you know, back then, it was way *more* than thousands of times bigger?

                              https://www.youtube.com/watch?v=YdOXS_9_P4U

                              aevaundefined Questo utente è esterno a questo forum
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                              aeva
                              scritto su ultima modifica di
                              #36

                              @rf they were so close lol

                              1 Risposta Ultima Risposta
                              • SnoopJundefined SnoopJ

                                @aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did

                                divine geometry is a helluva drug

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                                SnoopJ
                                scritto su ultima modifica di
                                #37

                                @aeva on the other hand getting extremely horny for triangles is both funny and kinda relatable, so

                                aevaundefined 1 Risposta Ultima Risposta
                                • SnoopJundefined SnoopJ

                                  @aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did

                                  divine geometry is a helluva drug

                                  aevaundefined Questo utente è esterno a questo forum
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                                  aeva
                                  scritto su ultima modifica di
                                  #38

                                  @SnoopJ we're still using spherical trig in astronomy today despite earth being an ellipsoid

                                  SnoopJundefined 1 Risposta Ultima Risposta
                                  • SnoopJundefined SnoopJ

                                    @aeva on the other hand getting extremely horny for triangles is both funny and kinda relatable, so

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                                    aeva
                                    scritto su ultima modifica di
                                    #39

                                    @SnoopJ mood

                                    1 Risposta Ultima Risposta
                                    • aevaundefined aeva

                                      @SnoopJ we're still using spherical trig in astronomy today despite earth being an ellipsoid

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                                      SnoopJ
                                      scritto su ultima modifica di
                                      #40

                                      @aeva well, yea, because astronomy doesn't really give a shit what shape the earth is anyway

                                      Glyphundefined 1 Risposta Ultima Risposta
                                      • SnoopJundefined SnoopJ

                                        @aeva well, yea, because astronomy doesn't really give a shit what shape the earth is anyway

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                                        Glyph
                                        scritto su ultima modifica di
                                        #41

                                        @SnoopJ @aeva everything is a sphere if you zoom out far enough

                                        aevaundefined 1 Risposta Ultima Risposta
                                        • Glyphundefined Glyph

                                          @SnoopJ @aeva everything is a sphere if you zoom out far enough

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                                          aeva
                                          scritto su ultima modifica di
                                          #42

                                          @glyph @SnoopJ i'm tired of all the spherical milky way conspiracy theorists

                                          SnoopJundefined 1 Risposta Ultima Risposta
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                                          Gli ultimi otto messaggi ricevuti dalla Federazione
                                          • aevaundefined
                                            aeva

                                            @kevingranade they did eventually redefine the kilogram as something other than robespierre's evaporating left nut at least

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                                          • aevaundefined
                                            aeva

                                            @luana I figure the smaller the city the lower the odds you end up with grosstopically overlapping structures, legally speaking

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                                          • Kevin Granadeundefined
                                            Kevin Granade

                                            @aeva at least all the measurement units are nailed down.
                                            https://www.nist.gov/pml/us-surveyfoot
                                            Well, ok it could be worse.

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                                          • Kevin Granadeundefined
                                            Kevin Granade

                                            @aeva I mean borders and locations of civil territories are actually definitively imaginary so that tracks.

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                                          • 🏳️‍🌈🎃🇧🇷Luana🇧🇷🎃🏳️‍🌈undefined
                                            🏳️‍🌈🎃🇧🇷Luana🇧🇷🎃🏳️‍🌈

                                            @aeva wouldn’t it matter more for smaller cities?

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                                          • .mau.undefined
                                            .mau.

                                            Quizzino della domenica: tutti primi

                                            @matematica - Se a+b+c=d con a,b,c,d primi, qual è il valore minimo di d?

                                            https://wp.me/p6hcSh-8Eo

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                                          • aevaundefined
                                            aeva

                                            time is fake, but as it happens space is also fake

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                                          • aevaundefined
                                            aeva

                                            anyways, somewhere in peru there's a town that is legally somewhere between 100 meters and 1 km off from where it actually is, and it'll be really funny if it ever gets big enough for that to actually matter

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