Avoid letting people down.
- marisca
- Yellow Admiral
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Re: Avoid letting people down.
Too little, too late. I feel deflated.
- Aja
- Yellow Admiral
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Re: Avoid letting people down.
.... Old hat now. Been on the radio all day.
Donald
Donald
- aquaplane
- Admiral of the White Rose
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Re: Avoid letting people down.
And there was I thinking that the equinox was when the sun crosses the equator and day and night are equal length.
I forgot about defraction, or was it refraction? The atmosphere bending light, which I forgot I knew about from doing celestial navigation years ago. Anyway, equal days and nights don't happen on the equinox, not even at the equator.
My head hurts now
I forgot about defraction, or was it refraction? The atmosphere bending light, which I forgot I knew about from doing celestial navigation years ago. Anyway, equal days and nights don't happen on the equinox, not even at the equator.
My head hurts now
Seminole.
Cheers Bob.
Cheers Bob.
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- Master Mariner
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Re: Avoid letting people down.
Although some of the inequality of the days and nights at the equinox is indeed due to refraction allowing us to see a sun which is in fact below the horizon, much more is due to the asymmetry of how we define day and night.
Consider the case of a hypothetical day when the time between the sun's hemidiameter crossing the horizon in the morning until it crosses it again at night is exactly half the time between that noon and the next. The length of day and night would still not be equal, because the day starts when the sun's rim appears above the horizon and ends when its rim disappears, so that day would be longer than that night.
Consider the case of a hypothetical day when the time between the sun's hemidiameter crossing the horizon in the morning until it crosses it again at night is exactly half the time between that noon and the next. The length of day and night would still not be equal, because the day starts when the sun's rim appears above the horizon and ends when its rim disappears, so that day would be longer than that night.
- claymore
- Admiral of the Green
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Re: Avoid letting people down.
That's all well and good - but whit if its pishing doon?Alan_D wrote:Although some of the inequality of the days and nights at the equinox is indeed due to refraction allowing us to see a sun which is in fact below the horizon, much more is due to the asymmetry of how we define day and night.
Consider the case of a hypothetical day when the time between the sun's hemidiameter crossing the horizon in the morning until it crosses it again at night is exactly half the time between that noon and the next. The length of day and night would still not be equal, because the day starts when the sun's rim appears above the horizon and ends when its rim disappears, so that day would be longer than that night.
Regards
Claymore

Claymore

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- Master Mariner
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Re: Avoid letting people down.
Claymore, are you confusing metrology with meteorology? I can sympathise, I have had trouble with my vowels since primary school.
- claymore
- Admiral of the Green
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Re: Avoid letting people down.
Ah can see youse fekkers need wan o ma basic fact o'life talks.
If yer wantin sae see ra sun - be that refraction, reflection or fekkin rephrasin, tae tell youse wither er not its day er fekkin nicht, there's rules.
1 - ef ets pishin doon yer hardly likely tae see ra fekkin sun.
2 if ye cannae see whether its dark or light, get alang tae specsavers
3 - if yeve time fer seeing tae ra minute whether we're gettin equal amounts, yer no busy enuff
Xxx
If yer wantin sae see ra sun - be that refraction, reflection or fekkin rephrasin, tae tell youse wither er not its day er fekkin nicht, there's rules.
1 - ef ets pishin doon yer hardly likely tae see ra fekkin sun.
2 if ye cannae see whether its dark or light, get alang tae specsavers
3 - if yeve time fer seeing tae ra minute whether we're gettin equal amounts, yer no busy enuff
Xxx
Regards
Claymore

Claymore
