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Re: Sine curve to approximate declination
From: Frank Reed CT
Date: 2004 May 19, 18:58 EDT
From: Frank Reed CT
Date: 2004 May 19, 18:58 EDT
Dan A wrote:
"I made a spreadsheet with 4 columns to get a look at this. "
Me, too. :-)
And wrote:
"It is common for the declination estimates to be off by up to half of a degree."
A big part of this error results from the fact that the ecliptic only looks like a sine curve. It's not a bad approximation, but the real curve has "broader shoulders" than a sine curve. It's easy to see this by imagining what the ecliptic would look like if the Earth's axis were tilted, say, 80 degrees instead of 23.45.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"I made a spreadsheet with 4 columns to get a look at this. "
Me, too. :-)
And wrote:
"It is common for the declination estimates to be off by up to half of a degree."
A big part of this error results from the fact that the ecliptic only looks like a sine curve. It's not a bad approximation, but the real curve has "broader shoulders" than a sine curve. It's easy to see this by imagining what the ecliptic would look like if the Earth's axis were tilted, say, 80 degrees instead of 23.45.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois