Irrelevant if you can take enough regular measurements when there is no cloud cover. Knowing the geometry of the earth and the axis of rotation, time and coordinates can be calculated.But what happens on a cloudy day?
Irrelevant if you can take enough regular measurements when there is no cloud cover. Knowing the geometry of the earth and the axis of rotation, time and coordinates can be calculated.But what happens on a cloudy day?
Nice! Who makes this sundial? If I am reading it correctly, it looks like 1415 or 2:15PM?A camera could take a photo of the crosshair shadow produced by this sundial.
View attachment 274526
When I was young (1980's) my parents had me use the sun to tell time along with the farm I worked on. I was told, plow this field but be back before the sun hits the horizon or be home for dinner when the sun is two handbreadths from the horizon. But for some reason I was not allowed to use the excuse of it got cloudy for being late for dinner. Before the era of GPS I looked at the sun's position in the sky to navigate through a city I was never in to determine North/South etc. To this day I can usually get the time correct to within an hour or so when outside working by just looking at the position of the sun. Brings back memories.But what happens on a cloudy day?
Glad you enjoyed my video!Saw this on the 'Tube. It's a teacher's project for his EE class in Thailand. I thought it was pretty cool. No IC's! I like how he did the mains counter/divider.
Video is 2 years old...Sorry if this has been posted/discussed before.
https://en.m.wikipedia.org/wiki/Bifilar_sundialNice! Who makes this sundial? If I am reading it correctly, it looks like 1415 or 2:15PM?
"Horas non numero nisi serenas"Edit: why are you only concerned with cloudy days?
I used to do that, growing up and working in California. Then one day I came out of a restaurant at noon in Singapore and couldn't find my way over to where I got out of the taxi.I often use the position of the sun to figure out the time and get my bearings.
When our kids were young I would show them how to make a sun dial in the sand whenever we went camping.
When driving in unknown territory I prefer to use visual cues rather than rely on GPS.
At night, when the moon is visible, you can also get a pretty good estimate of the time from looking at the terminator on the moon and imagining that you are standing "on top" of the moon, from your perspective.When I was young (1980's) my parents had me use the sun to tell time along with the farm I worked on. I was told, plow this field but be back before the sun hits the horizon or be home for dinner when the sun is two handbreadths from the horizon. But for some reason I was not allowed to use the excuse of it got cloudy for being late for dinner. Before the era of GPS I looked at the sun's position in the sky to navigate through a city I was never in to determine North/South etc. To this day I can usually get the time correct to within an hour or so when outside working by just looking at the position of the sun. Brings back memories.
Never thought of doing that. I will have to try that and see how accurately I can guess the time at night.At night, when the moon is visible, you can also get a pretty good estimate of the time from looking at the terminator on the moon and imagining that you are standing "on top" of the moon, from your perspective.