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jrbarnett
Eyepiece Hooligan
Reged: 02/28/06
Posts: 4346
Loc: Petaluma, CA
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I think we're examining the problem of "red Sirius" accounts from ancient Western sources too much through our modern lens. Careful examination of the thread, both in favor of Sirius being red and against, reveals a common set of assumptions regarding the motivations and context of the ancients when making observations.
In the the Hellenic world, there was no distinct beast called "science". Fields we today classify as "metaphysics", "astrology/mysticism", "astronomy and physics," "mathematics", etc., were not distinct in ancient times. Ergo, the purpose of an ancient observer in conducting observations is unlikely to have been the same as our purpose for conduction similar observations today.
Now for some speculation. While observing bright stars like Sirius at the moment of their rising and setting at different times of the year is not the most common context of observation today, in the Ancient near east and Mediterranean it was likely the predominant context for such observations. Descriptions of "flaming" or "fiery" Sirius seem particularly apt for a Sirius just risen, viewed through miles of turbulent atmosphere. Perhaps earlier observations describing low elevation observations of Sirius as "like fire" were perpetuated by later writers.
In any case, I think that it is crucially important to recognize that what the ancients thought they saw when they looked at the night sky is not what you and I think we see. To understand the "what" of what they saw, I think you have to mindful of the "why" as in why were they observing in the first place. In my view, the later learned records by non-observers like Cicero were likely based on the records of earlier observers like Ptolemy. Ptolemy, on the other hand, was as much a meta-physicist and mystic as astro-physicist. I wouldn't be surprised to learn that his observations of Sirius were conducted near the horizion, often at or near sunrise or sunset, and that his purpose was not simply self-indulgent "scientific curiosity" in making the observations.
Regards,
Jim
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"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
- Sir Issac Newton
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Uncle Burnout
super member
Reged: 08/06/03
Posts: 115
Loc: California (Bay Area)
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You are spot on in your thinking -- the question is not really "was Sirius red in antiquity", but rather "did Sirius sometimes appear or was described as red (or other color) in antiquity, and what did that mean".
We have a quote from Hephaestion of Thebes (Ceragioli, note 72 has the Greek text) describing how if the star's color upon rising was inspected as an omen. Curiously, he menitions that the star is "white" ("leukos"). This agrees with Hyginus' description of Sirius as being remarkable for its "candor", which is usually from the context interpretted as "brightness", but almost certainly implies a white tint. Add to these, Manilius and Avienus, who explicitly describe the star Sirius as "blue" or perhaps "blue-white".
Given this type of interpretation, we can perhaps understand the truly unambiguous references to Sirius' color as red (not its fierieness or the color of Canis the constellation), which actually only seem to occur a few times: In Seneca, where we're told the celestial bodies have not inherent color, but acquire it through atmospheric effects (passage cited by Crossen, although not in full context), and in Horace where he refers to Sirius as "rubra"(not cited in Crossen) in the context of extreme heat.
Since we can see that there was an awareness and assumed meaning in the color seen in Sirius, perhaps Ptolemy's characterization of the star as "hypokirros" is a guess at the star's "actual" color, since we don't know if he shared an assumption with Seneca that celestial bodies have no inherent color. There is very little context to make a guess, although several astronomers (most notably See, whom Crossen seems to follow) took up the task and piled up dubious citations leading ultimately to the conclusion that the ancients saw Sirius as a "fiery red" star all the time.
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Thomas44
super member
Reged: 10/26/09
Posts: 101
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The article was a bit long but anyhow it's worth the read. Pretty interesting actually.
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www.laserpointers.co.uk
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7331Peg
professor emeritus
Reged: 09/01/08
Posts: 725
Loc: North coast of Oregon
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I've really enjoyed the discussions on this topic, and I hesitate to jump in here because I think most everything that can be said has been said.
One thing that does intrigue me, though, is the possibility of seeing Sirius just as it appears over the horizon. I'm not referring to it simply being ten or twenty degrees above the horizon, but just a few degrees above it. In this day and age that would be unlikely in most of the world, but in the period of time that is being discussed here, it would seem like it might be possible due to the lack of pollutants in the air.
If you were out in the middle of an empty plain - or on the Mediterranean with a clear view of the eastern horizon - back in that era, and if you could actually catch Sirius a couple of degrees above the horizon - especially on a warm August morning - chances are pretty darn good it would be red.
John
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Crossen
member
Reged: 07/14/08
Posts: 87
Loc: Vienna
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John,
I lived and worked on our family farm until I was 39 years old (with a 5-year exile in Minneapolis to attend the U of MN), and during the last ten years of that period was an active observer--as well as frequently outside during evenings doing normal farm work. Our farm was two miles from the nearest village out under extremely dark skies. During that decade I had the opportunity to observe Sirius rising or setting dozens of times under a wide variety of atmosphere conditions. When the atmosphere was thick with dust or humidity the star was too dimmed to have much color: when it got a few degrees above the horizon one might have described it as a sort of "dull ruddy", which quickly faded into a pale yellow and then off-white. But under average conditions the star appeared as a scintillating gem best described by Aratos' "many-colored" (poikilos). Red, yellow, and blue-white predominated, alternating almost too quickly to be sure you really saw them. It was like looking at the star through a fractured piece of glass and impossible under those circumstances to judge the star's "rest color". It's always been clear to me that Aratos was describing the rising or setting Sirius, not the Sirius ten or twenty degrees above the horizon.
Craig Crossen
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Uncle Burnout
super member
Reged: 08/06/03
Posts: 115
Loc: California (Bay Area)
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Craig,
That observation of yours convinces me that you must be sincere in your aims, although (sorry) a little weak in Greek and Latin. Please consider re-examining this topic before publishing your book -- there is much still in the topic that should interest observers without posing the stumblingblock of an actual change in Sirius' color. At least read Ceragioli and consult Greek and Latin scholars for review.
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tatarjj
Pooh-Bah
Reged: 04/20/04
Posts: 1134
Loc: Austin, TX
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Maybe some ancients reported Sirius as being red because the Sirians were launching a red laser-powered light sail our way that crashed in Roswell in 1947! No, I don't believe that, but it would make a good conspiracy theory 
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John T.
Austin, TX
25" f/4.2 Dob
18" Obsession #701
4" Stellar Vue Achromat
8X56 Binos
Edited by tatarjj (10/31/09 08:44 PM)
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