kevinpalm
I have built four simple sundials (horizontal, equitorial, vertical decliner and polar). All show the same time all day, every day. However, they do not show 'watch time' after adjusting for the equation of time, and longitude.
For example I live at longitude 122.5 W which is 2.5 degrees west of the Pacific Standard Time meridian, so I have to add 10 minutes to my sundial time to adjust for longitude.
On January 30 the equation of time is +13.4 minutes. On that day I would expect to add that plus the 10 minutes longitude difference for a total of 23.4 minutes to my sundial time to get Pacific Standard Time.
On January 30th my sundials were all 15 minutes behind my watch, not 23 minutes.
I can't figure out where the extra 8 minutes have gone. Any suggestions? Any idea where I might look further?
For example I live at longitude 122.5 W which is 2.5 degrees west of the Pacific Standard Time meridian, so I have to add 10 minutes to my sundial time to adjust for longitude.
On January 30 the equation of time is +13.4 minutes. On that day I would expect to add that plus the 10 minutes longitude difference for a total of 23.4 minutes to my sundial time to get Pacific Standard Time.
On January 30th my sundials were all 15 minutes behind my watch, not 23 minutes.
I can't figure out where the extra 8 minutes have gone. Any suggestions? Any idea where I might look further?