Sunrise/Sunset is off by 16 minutes since 1861 Farmer's Almanac Published

Originally posted by MidnightTide
Actually it is already proven that massive earthquakes do slightly move the Earth's axis, so yes the days do grow shorter.

An example is the Japanese Earthquake:

www.jpl.nasa.gov...

Yes. 1.8 microseconds. Basically negligible. When you use Farmer's Alamac as 100% accurate you are just begging to be wrong.

A point already made but the Farmers' Almanac (as great as it is) was not scientifically computed nor based off exact measurements in 1861. There were no atomic clocks, no precise measurements, etc.

So could it be said that the farmers of 1861 are 16 minutes off? A valid question to this I believe....

Originally posted by ownbestenemy
A point already made but the Farmers' Almanac (as great as it is) was not scientifically computed nor based off exact measurements in 1861. There were no atomic clocks, no precise measurements, etc.

So could it be said that the farmers of 1861 are 16 minutes off? A valid question to this I believe....

There is nothing wrong with the sunrise and sunset times for Boston listed in the 1861 Farmer's Almanac. What many of you fail to understand is that there was no such thing as Eastern Standard Time in 1861, as the use of time zones had not been established.

Boston was using local solar time in 1861 and the difference between that and Eastern Standard time, which Boston now uses, is approx. 15 mins 46 secs.

Refer to my post here: www.abovetopsecret.com...

Originally posted by erwalker
This is easily solved with some simple arithmetic and knowing the longitude of the place you're interested in..
Greenwich England is at 0° Longitude.
Boston is at 71.0603° W Longitude.
The actual time in Boston, as opposed to the Eastern Standard Time, can be figured out as follows:

71.0603°/360°=0.197390
0.197390*24 hrs=4.73735 hrs or 4 hrs 44.2 mins behind Greenwich

The Eastern Standard Time zone is 5 hrs behind Greenwich. The difference is approx. 16 mins. So when it is 12 noon in the EST, it would actually be 12:16 in Boston if you set your clocks to read noon when the sun was at its highest point.

Doing the same calculation for Washington DC (at 77.0300° W) works out to 5.13533 hrs or 5 hrs 8.1 mins behind Greenwich for a difference of approx. 8 mins. So Washington is actually at 11:52 AM when it is noon in the EST.

The difference between Boston and Washington is 24 mins, as stated in the linked comparative time-table.

Well done! I apologize for this thread. I posted a link on another forum to the 1861 almanac the OP used at the start of this thread, and because of the way in which I was using it (I was only interested in the declination of the sun at that time - "how far north the sunrise/sunset should be at summer solstice") I didn't bother to explain the difference in time shown by the almanac due to the time zone vs solar time issue. The OP must have seen my post, grabbed the link, and made this thread over here in this forum later the same day. I wish they had simply consulted me first and asked about the apparent discrepancy, but I'll try to be more conscious of how others may misinterpret the things I post in the future, my apologies and again, excellent post.

reply to post by erwalker


What are you arguing in your response to me? I think you just responded for responding sake; rather than realize that I was contending the notion that the rise and fall of the sun in our sky was "off". Comprehension is fantastic really.

Please though, give me more lessons....

reply to post by ownbestenemy


From your response, I inferred that you suspected that the 16 min difference was down to an inability to perform sufficiently precise measurements due to a lack of modern technology. The technology available in 1861 was certainly precise enough to provide sunrise and sunset times down to the nearest minute. In fact, they are probably as precise as you would find in the local paper today.

So could it be said that the farmers of 1861 are 16 minutes off? A valid question to this I believe....

Only in the sense that the Farmer's Almanac was using the solar time for Boston, which is what was used at the time, and that differs from Eastern Standard by approx. 16 mins. It is valid to ask why there is a difference if you are not aware the 4 time zones in the US were only adopted in the US in by the railways in 1883 and that standard time did not become law in the US until 1918.

It is wrong to suggest that the difference is down to earthquakes or other natural phenomena as some suggested or imprecise measurements as you seemed to suggested.