For experts on celestial navigation...
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Join Date: Jun 2002
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For experts on celestial navigation...
Here's an interesting one.
I'm currently reading Gann's 'Fate is the Hunter' which most of you are probably familiar with.
Well, while flying somewhere over northern Canada, our protagonist decides to try his hand at a bit of Celestial Navigation and tries to plot his position by sighting on Dubhe in the constellation Ursa Major. He spies this star out of a cabin window. All well and fine here. Ursa Major is a circumpolar constellation and quite easily visible (if the time is right) out a cabin window. Our hero, subsequently goes to the toilet (geographically, not biologically
) at the back of the aircraft which for some reason has a window in the ceiling out of which he spies Sirius, the second brightest star in the sky. Now my astronomy might be a bit rusty but if I remember correctly Sirius is well below the Celestial equator and therefore never 'rises' much above the southern horizon for observers in northern climes and even less so for anyone so far north as Canada. So I find it hard to imagine anyone spying Sirius while looking vertically through the ceiling of an aircraft flying so far north.
In his defense, our erstwhile hero earlier in the book claims to not being very good at Astronomy and this is his first 'operational' attempt at celestial navigation.
Anyone got any thoughts on the matter?
Irlandés
(edited because I can't spell!
)
I'm currently reading Gann's 'Fate is the Hunter' which most of you are probably familiar with.
Well, while flying somewhere over northern Canada, our protagonist decides to try his hand at a bit of Celestial Navigation and tries to plot his position by sighting on Dubhe in the constellation Ursa Major. He spies this star out of a cabin window. All well and fine here. Ursa Major is a circumpolar constellation and quite easily visible (if the time is right) out a cabin window. Our hero, subsequently goes to the toilet (geographically, not biologically
) at the back of the aircraft which for some reason has a window in the ceiling out of which he spies Sirius, the second brightest star in the sky. Now my astronomy might be a bit rusty but if I remember correctly Sirius is well below the Celestial equator and therefore never 'rises' much above the southern horizon for observers in northern climes and even less so for anyone so far north as Canada. So I find it hard to imagine anyone spying Sirius while looking vertically through the ceiling of an aircraft flying so far north.In his defense, our erstwhile hero earlier in the book claims to not being very good at Astronomy and this is his first 'operational' attempt at celestial navigation.
Anyone got any thoughts on the matter?
Irlandés
(edited because I can't spell!
)
Join Date: Apr 2000
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Armed with my Astronomy O level, let me try a response!
Where I am (52 degrees north) Sirius is an autumn star, and probably gets to around 20 degrees above the horizon at maximum. Therefore, it would be visible up to around 72N in theory, although for a short time only.
Doubtless someone else will be a little more accurate with the figures
Where I am (52 degrees north) Sirius is an autumn star, and probably gets to around 20 degrees above the horizon at maximum. Therefore, it would be visible up to around 72N in theory, although for a short time only.
Doubtless someone else will be a little more accurate with the figures
Join Date: May 2002
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Your right Irlandes, Sirius would be impossible to see out of a vertical looking window. I studied astrophyics at uni and have just consulted the books, as SLF said, Sirius would be visible up to 72N..ish in good viewing conditions, this figure would increase if you were flying in an aircraft as your altitude has increased however flying in north Canada Sirius would still appear low on the horizon as viewed out a cabin window and would be impossible to see out a vertical looking window, unless of course the aircraft was pulling some G's and doing a serious turning manoeuvre in which case the last thing you'ed be worried about was the stars especially when you're sat on the toilet.
