9 August 2018 at 12:01 pm #574104Jeremy ShearsParticipant9 August 2018 at 2:43 pm #579847Peter MulliganParticipant
What a fascinating article Jeremy, when you think about it with the fabulous pitch black skies of the Australian outback, its a cert that these indigenous people who have lived there for thousands of years, would have noticed the variations in brightness of bright stars such as Betelgeuse and Antares: and may be even fainter stars?10 August 2018 at 12:27 pm #579856David SwanParticipant
Thanks for pointing out this article, Jeremy.10 August 2018 at 2:24 pm #579857Grant PrivettParticipant
I’m curious. I know that like the Hawaiians the Australians relied on oral history rather than written records, but I have no idea where they stood with regard number systems and calendars? Presumably they spotted variation but didnt record the period? Have I got that right?26 December 2018 at 11:55 am #580438Tracie HeywoodParticipant
I do sometimes wonder how much experience authors of articles such as this have of the stars that they are writing about.
Yes, as the author states “it is easy for inexperienced observers to detect the variability of Betelgeuse over its range in brightness from V = 0.0 to V = 1.3“. However, the key word here is “inexperienced”. Are they really detecting changes in the brightness of Betelgeuse itself, or is it just scatter due to inexperience?.
The major challenge regrading visual monitoring of Betelgeuse is that with it being one of the brightest stars, its comparison stars such as Procyon are a long away from it on the sky – and thus potentially affected to a different extent by factors such as haze. It is easy to “see” Betelgeuse to be “significantly brighter than Procyon” , when Procyon is somewhat lower in the eastern sky and dimmed by haze or “greatly fainter than Procyon” when Betelgeuse is somewhat lower in the western sky.
I have included my light curve from the past 10 years to illustrate that the normal range of Betelgeuse is no more than a few tenths of a magnitude. My observations of Betelgeuse go back around 40 years and, other than when observed under poor sky conditions or when low in the sky, my estimates have not ventured far from the range shown here.26 December 2018 at 3:37 pm #580439Grant PrivettParticipant
Did they also record changes in Mira? You would think that if they are paying attention that closely then they should have.26 December 2018 at 4:58 pm #580440Dominic FordKeymaster
Well said, Tracie.
It’s dangerous to assume that ancient observers had anything like the mindset of a modern amateur astronomer.
The ancient Greeks were so certain that the sky was unchanging that they insisted novae and comets were inside the Earth’s atmosphere. The experiment that Tycho Brahe did to disprove this wasn’t technically difficult — he simply measured the parallax of a nova and showed it was less than the Moon’s. The reason this had to wait until the 16th century wasn’t lack of technology, it was just that nobody was asking the right question.
I don’t doubt that in the whole history of Australia, there wasn’t some bright spark who said “Hey, Betelgeuse looks bright tonight!”. But that doesn’t count as a “discovery”. We don’t say that Hipparcos or Flamsteed “discovered” Uranus, simply because they observed it and marked it on star charts. We credit the discovery to Herschel, because he was the first to realise it wasn’t just another a faint star.
As Tracie says, ancient people probably ascribed any variability they observed to sky conditions. In most cases, that was probably the correct interpretation. In the absence of any evidence that their thinking went deeper than that, I think it’s nonsense to speculate further!
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