**Human height & solar declination** is a concept for using human heights to determine solar declinations.

## Definition Edit

On Earth, the axis tilts at 23.44°, corresponding to human heights ranging from 4'6"3.36‴ (0.8224 ta, 137.87 cm) at winter solstice or solar nox to 6'5"8.64‴ (1.1776 ta, 197.41 cm) at summer solstice or solar noon. On vernal and autumnal equinoxes or solar morn and solar eve, respectively, the human height is exactly 5'6" (1.0000 ta, 167.64 cm). A 1 inch difference of human height is a 2° difference of solar declination. If a person is shorter than 4'6"3.4‴ or taller than 6'5"8.6‴, then the "imaginative solar declination" of the sun is lower than −23.44° or higher than +23.44° respectively. For example, a person standing four feet tall has a solar declination of −36°, whereas a person standing seven feet tall has a solar declination of +36°. This concept should only apply to adults and adolescents after puberty, because before puberty a person is so short that its solar declination can be lot less than −36°. To determine the solar declination using the height, the equation is

$ \delta = 2(h - \iota) $

where $ \delta $ is the solar declination, $ h $ is the height, and $ \iota $ is the equinoxal height, which is 5'6".

For example, if a person is standing 63 inches tall or 5'3", then it is calculated as 2(63−66) = 2(−3) = −6. So if a person is standing 63 inches tall or 5'3", then the solar declination would be −6°.

Let's do the opposite way, to convert solar declination into height, the equation is

$ h = \iota + \frac{\delta}{2} $.

For example, if the solar declination is +16°, then it is calculated as 66+(16/2) = 66+8 = 74. So if the solar declination is +16°, then a person would stand 74 inches tall or 6'2".

## Season method Edit

Since the same solar declination occur twice each year, to determine dates using this concept, ones must be taken account of their birthdates. If the birthdate is between December 21 or 22 (winter solstice) and June 21 or 22 (summer solstice), then the solar declination (depending on height) and the northward motion of the sun is determined. Whereas if the birthdate is between June 21 or 22 (summer solstice) and December 21 or 22 (winter solstice), then the solar declination (depending on height) and the southward motion of the sun is determined. If their birthdates take place on the solstice, then the movement of the sun can be determined depending on the date. If the birthdate is on the summer solstice, the direction the sun moving is north, whereas if the birthdate is on the winter solstice, the direction the sun moving is south. Using the solar declination given by height and which way the sun is moving, the date and thus season in a current year can be determined about when that value of solar declination take place. After this determination, sunrise and sunset times can then be determined depending on where a person lives.

## Pardie method Edit

An alternative method of using human height to determine solar declination other than the season method just mentioned is the pardie method. In this method, the height of a person determine the time of the day instead of the day of the year. A 6'5"8.6‴ person is at solar noon, a 4'6"3.4‴ person is at solar nox, and 5'6" person is halfway between solar noon and solar nox, around solar morn or solar eve. The northward motion of the sun equivalence is during the solar morning (AM) while the southward motion of the sun equivalence is during the solar evening (PM). Like the season method, the pardie method requires the birthdate to determine if the sun is moving north or south. Then the birthdate can be converted into a time based on the day of one's birthdate.

Every minute, 3.9452 days passed during a 365-day year (standard year) and 3.9344 days passed during a 366-day year (leap year). This equivalence can be used to convert time into date (especially from birthdate into time) from solar noon or solar nox. The equation is

$ d = \frac{t \plusmn \sigma}{\tau} $

where $ d $ is the date equivalence of time, $ t $ is the time, $ \sigma $ is the solar noon or solar nox, and $ \tau $ is the time-date constant at 3.9452 in standard years or 3.9344 in leap years.

For example, during a 365-day year, if the time is 1:38 AM and if the solar nox is 12:48 AM, which is a 50-minute difference, then the date equivalence of the time is calculated as 50/3.9452 = 12.6736 which is rounded to 13. So 13 days after the winter solstice on December 21 would be January 3.

Let's do the opposite way, the equation is

$ t = \tau(d \plusmn \sigma) $

where $ t $ is the time equivalence of the date, $ \tau $ is the time-date constant at 3.9452 in standard years or 3.9344 in leap years, $ d $ is the date, and $ \sigma $ is the summer solstice or winter solstice.

For example, if the date is July 19 and the summer solstice fall on June 21 during a leap year and if the solar noon is at 12:51 PM, then the time equivalence is calculated as 3.9344(28) ≈ 110. So 110 minutes after the solar noon at 12:51 PM would be 2:41 PM.

## Example Edit

PlanetStar has a height of 5'4"10.6‴ (0.9831 ta, 164.80 cm), corresponding to his solar declination of −2.23° and since his birthdate is July 19 during the period when the solar declination is decreasing, then his 2014 date would be September 29 when the sun rises at 6:47 AM and sets at 6:36 PM while living in Tinley Park, Illinois.

The solar noon of September 29 is approximately 6.717 days after the autumnal equinox, so we have 6.717*3.9452≈26.50. We use the constant 3.9452 since 2014 is the standard year. So 26½ minutes after the solar eve at approximately 6:41:30 PM is 7:08 PM. So the time equivalence of September 29, 2014 is 7:08 PM, 32 minutes after sunset.

These correspond that PlanetStar is an autumn person, a forenox person, and a night person.

## Average heights around the world Edit

The average height around the world is near the equinox points. In the United States, the average height is about 5'6"8‴ (1.010 ta, 169.3 cm), which equates to the solar declination of +1.3°, which is taller than most countries around the world. The tallest country is The Netherlands, which has the average height about 5'9"6‴ (1.053 ta, 176.5 cm), which equates to the declination of +7°. The shortest country is Indonesia, which has the average height about 5'0"0‴ (0.910 ta, 152.5 cm), which equates to the declination of −12°.

## Related pages Edit

- Birthheight
- Tald — a unit useful for human heights