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Question: Judging High Tide by the Moon
Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Cheers |
#2
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Question: Judging High Tide by the Moon
Navigator wrote:
The devil _is_ in the detail and is it ever 12 hours???? What part of 'find lunar noon' are you ignoring in lieu of trolling for nanosecond-precise astronomical timing? -- Wally www.forthsailing.com www.wally.myby.co.uk |
#3
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Question: Judging High Tide by the Moon
"Navigator" wrote in message
... Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Why not? What's the problem? Or are you making the sophomoric argument that its very unlikely to be "precisely" 12 hours? It certainly isn't hard to find places and times where its within a couple of minutes. Certain latitudes are more favorable than others for this situation to exist, but there's nothing the precludes it. Have a go with: http://aa.usno.navy.mil/ select "Data Services" and then "Table of sunrise/sunset ..." |
#4
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Question: Judging High Tide by the Moon
No, I'm trying to get people to think about the relationship between
altitude and period between rise and set for a fixed lunar orbital period. Cheers Jeff Morris wrote: "Navigator" wrote in message ... Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Why not? What's the problem? Or are you making the sophomoric argument that its very unlikely to be "precisely" 12 hours? It certainly isn't hard to find places and times where its within a couple of minutes. Certain latitudes are more favorable than others for this situation to exist, but there's nothing the precludes it. Have a go with: http://aa.usno.navy.mil/ select "Data Services" and then "Table of sunrise/sunset ..." |
#5
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Question: Judging High Tide by the Moon
Sounds more like you don't know what you're talking about.
"Navigator" wrote in message ... No, I'm trying to get people to think about the relationship between altitude and period between rise and set for a fixed lunar orbital period. Cheers Jeff Morris wrote: "Navigator" wrote in message ... Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Why not? What's the problem? Or are you making the sophomoric argument that its very unlikely to be "precisely" 12 hours? It certainly isn't hard to find places and times where its within a couple of minutes. Certain latitudes are more favorable than others for this situation to exist, but there's nothing the precludes it. Have a go with: http://aa.usno.navy.mil/ select "Data Services" and then "Table of sunrise/sunset ..." |
#6
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Question: Judging High Tide by the Moon
Are you saying that the peiod between rise and set is fixed?
Cheers Jeff Morris wrote: Sounds more like you don't know what you're talking about. "Navigator" wrote in message ... No, I'm trying to get people to think about the relationship between altitude and period between rise and set for a fixed lunar orbital period. Cheers Jeff Morris wrote: "Navigator" wrote in message ... Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Why not? What's the problem? Or are you making the sophomoric argument that its very unlikely to be "precisely" 12 hours? It certainly isn't hard to find places and times where its within a couple of minutes. Certain latitudes are more favorable than others for this situation to exist, but there's nothing the precludes it. Have a go with: http://aa.usno.navy.mil/ select "Data Services" and then "Table of sunrise/sunset ..." |
#7
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Question: Judging High Tide by the Moon
Are you claiming its broken?
There are a number of factors that determine the time between moonrise and moonset. However, there is no reason why a 12 hour duration can't occur, and no reason why it can't happen from 4pm to 4am. Now you can claim that you were "trying to get people thinking about something" but I claim you have no idea about lunar noon and it relationship to the tides, and that you had some bizarre notion that a 12 hour duration was not possible. "Navigator" wrote in message ... Are you saying that the peiod between rise and set is fixed? Cheers Jeff Morris wrote: Sounds more like you don't know what you're talking about. "Navigator" wrote in message ... No, I'm trying to get people to think about the relationship between altitude and period between rise and set for a fixed lunar orbital period. Cheers Jeff Morris wrote: "Navigator" wrote in message ... Wally wrote: Navigator wrote: What location has moon rise and set 12 hours apart? Virtually anywhere, I'd guess - just had a look at moon rise and set for some random locations (Glasgow, Jerusalem and Canberra), for today, and they're all a shade over 12 hours apart. If rise/set are close to due east/west, then the time for the moon to traverse the sky will be about 12 hours - think about the solar equinoxes, where the sun rises/sets due east/west. I dare say this princple won't hold at extreme latitudes. The moon passes the due east/west points twice in its mo(o)nthly cycle. The devil _is_ in the detail and is it ever 12 hours???? Why not? What's the problem? Or are you making the sophomoric argument that its very unlikely to be "precisely" 12 hours? It certainly isn't hard to find places and times where its within a couple of minutes. Certain latitudes are more favorable than others for this situation to exist, but there's nothing the precludes it. Have a go with: http://aa.usno.navy.mil/ select "Data Services" and then "Table of sunrise/sunset ..." |
#8
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Question: Judging High Tide by the Moon
Jeff Morris wrote: Are you claiming its broken? There are a number of factors that determine the time between moonrise and moonset. However, there is no reason why a 12 hour duration can't occur, and no reason why it can't happen from 4pm to 4am. Yes, but is the period from rise to set at a fixed location constant? And yes I'm trying to get some thinking going. Cheers |
#9
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Question: Judging High Tide by the Moon
Navigator wrote:
No, I'm trying to get people to think about the relationship between altitude and period between rise and set for a fixed lunar orbital period. Not so much a side-step, as a stumble. -- Wally www.forthsailing.com www.wally.myby.co.uk |
#10
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Question: Judging High Tide by the Moon
C'mon you can try better than that.
Cheers Wally wrote: Navigator wrote: No, I'm trying to get people to think about the relationship between altitude and period between rise and set for a fixed lunar orbital period. Not so much a side-step, as a stumble. |
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