Would it? - I need to think about that! Even if it's true, I suppose one could have a complicated 'scale' which took the time of year into account.
Indeed. Thanks.
Kind Regards, John
Electrical Question in 'Pub Quiz'
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Kind Regards, John
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...and of course at the poles where the latitude is 90° and the gnomon would be vertical.
Imagine 6am or 6pm with vertical pin and difference between
No, I got that wrong.
January and June - except it will be dark in January.
January and June - except it will be dark in January.
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I'm still thinking (and 'imagining') - but, as I said, I think that issue could (if necessary) be addressed (using just 'a vertical pin') with an 'appropriate ['complicated'] scale', couldn't it?
Kind Regards, John
Not really.
Sorry I am late boss, my sun dial was 40 minutes slow......
Just imagine your vertical pin at the equator.
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So a sun dial is made for a latitude, and the length of shadow shows month and position shows hour, and once in the tropics you could not use it for time without knowing the month. Never really thought about it before.
If the problem (which I'm trying to get my head around) is that the shadow will be in different places at the same time of day at different times of the year, then a 'scale', which had curved lines (for different times of year) would accommodate that, wouldn't it?
Kind Regards, John
What's the problem then? The length of the shadow (up the side of the partial 'soup bowl') will then surely always indicate the correct time, won't it - after all, at the equator, there is no difference (in sun position) between January and June, is there? What am I missing?
Kind Regards, John
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With some exceptions like the Jaipur Mantar where 1 mm = 1 second most sun dials are not that accurate.
When I started work you were expected +/- 5 minutes from official start time, but later I worked where you would be docked 15 minutes if 1 minute late, and with bell to bell working was expected to clock on 5 minutes before time as they said it took that long to put overalls and boots on.
I know my sister went to work by train, as she said if the train is late it is accepted, if your late in a car, it does not matter if a massive crash, it was you should have set out earlier.
Today I sign on for safety so they know who is on site, and we do enter time, but no one really cares what time you put, whole place works at a leisurely pace, the trains are not permitted to go any more than 15 MPH.
When I started work you were expected +/- 5 minutes from official start time, but later I worked where you would be docked 15 minutes if 1 minute late, and with bell to bell working was expected to clock on 5 minutes before time as they said it took that long to put overalls and boots on.
I know my sister went to work by train, as she said if the train is late it is accepted, if your late in a car, it does not matter if a massive crash, it was you should have set out earlier.
Today I sign on for safety so they know who is on site, and we do enter time, but no one really cares what time you put, whole place works at a leisurely pace, the trains are not permitted to go any more than 15 MPH.
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Yes missing a bit, parts of the earth where the sun can be over head is between the tropics, where between the two the sun is over head depends on the time of year.
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Remember you also need a chart showing the Equation of Time. Solar time can be up to 16 min wrong.
No, because the 'pin' and shadow are straight.
You would need to specify a single varying point on the straight shadow for different times of year.
Just lean the pin to the latitude and all is solved.
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