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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>From:</b> extropy-chat <extropy-chat-bounces@lists.extropy.org> <b>On Behalf Of </b>John Clark via extropy-chat<br><b>Subject:</b> [ExI] Betelgeuse again<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:13.5pt'>Betelgeuse </span><span class=gmaildefault><span style='font-size:13.5pt;font-family:"Arial",sans-serif'>continues to fall in brightness, 2 months ago it was the 10th brightest star in the sky, as of December 28 it had dropped to number 21. Nobody seems to know if that means anything important but it's certainly odd.</span></span><o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span class=gmaildefault><span style='font-size:13.5pt;font-family:"Arial",sans-serif'>John K Clark <o:p></o:p></span></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>There is an excellent article on Sky and Telescope<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><a href="https://www.skyandtelescope.com/observing/fainting-betelgeuse/">https://www.skyandtelescope.com/observing/fainting-betelgeuse/</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Looks to me like it has gone really active in the last decade or so. It might also be that we have a pile of ground-based amateur telescopes on this, collecting piles of data. The CCD arrays became really practical around 10 yrs ago, so any yahoo with a couple thousand bucks worth of equipment can take scientifically-useful data. You would need about a 20 cm telescope, plenty of those available cheap online, a CCD camera, a tracker, a computer to collect and store the data.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Fun note on the streaky nature of that data: there are waaaay more telescopes doing business while Betelgeuse is visible at convenient observing times and is far from the sun. We can still do brightness measurements when it is closer to the sun, but it requires more expensive gear. For the next few month, we get lots of data.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>If you are a veteran star-gazer, the change in Betelgeuse this cycle is easy to see, without instruments. We may get to see a terrific celestial show sometime in the next 100k years.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>spike<o:p></o:p></p></div></div></div></body></html>