Line of Position: Difference between revisions
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* [http://www.screencast.com/users/moleski/folders/Jing/media/73a20fbf-e651-4b47-88a3-3e0a01c14324 Sun's motion from solstice to solstice] | * [http://www.screencast.com/users/moleski/folders/Jing/media/73a20fbf-e651-4b47-88a3-3e0a01c14324 Sun's motion from solstice to solstice] | ||
== Do all observers see the sun at the same location at dawn? == | == Do all observers see the sun at the same location at dawn? == | ||
Pretty nearly. It doesn't vary as much as I predicted from drawing 2 dimensional pictures of the 3 dimensional reality. | |||
I collected these charts and tables on 11 September 2010, which is close to the fall equinox. At dawn, someone near Buffalo would see the sun at 83.1 degrees, which would generate LOP perpendicular to the sun sighting of 353-173. The sunrise azimuth at Howland would be 85.59 and 85.65 at Niku, giving a LOP of 355-175. | |||
I don't know whether the difference is due to the earth not being a perfect sphere or solely to the difference in the latitude of the observers. | |||
Source: [http://www.sunearthtools.com/dp/tools/pos_sun.php www.sunearthtools.com - Sun position calculator:] | Source: [http://www.sunearthtools.com/dp/tools/pos_sun.php www.sunearthtools.com - Sun position calculator:] | ||
=== Howland === | === Howland === | ||
{| | {|{{Prettytable}} | ||
|- | |- | ||
|Latitude | |Latitude | ||
| Line 10: | Line 16: | ||
|Longitude | |Longitude | ||
|176.61624 | |176.61624 | ||
|- | |||
|Sunrise Azimuth | |||
|85.59 | |||
|} | |} | ||
<div align="center"> | <div align="center"> | ||
| Line 17: | Line 26: | ||
=== Niku === | === Niku === | ||
{| | {|{{Prettytable}} | ||
|- | |- | ||
|Latitude | |Latitude | ||
| | |4.67792 | ||
|- | |- | ||
|Longitude | |Longitude | ||
| | |174.5196 | ||
|- | |||
|Sunrise Azimuth | |||
|85.65 | |||
|} | |} | ||
<div align="center"> | <div align="center"> | ||
| Line 31: | Line 43: | ||
=== Near Buffalo === | === Near Buffalo === | ||
{| | {|{{Prettytable}} | ||
|- | |- | ||
|Latitude | |Latitude | ||
| Line 38: | Line 50: | ||
|Longitude | |Longitude | ||
|78.82926 | |78.82926 | ||
|- | |||
|Sunrise Azimuth | |||
|83.1 | |||
|} | |} | ||
<div align="center"> | <div align="center"> | ||
| Line 43: | Line 58: | ||
[[File:2010-09-11 Buffalo table.png]] | [[File:2010-09-11 Buffalo table.png]] | ||
</div> | </div> | ||
== Gallery == | |||
[[File:Terminator.png]] | |||
[[File:Summer solstice 2 overlaid.png]] | |||
[[File:Winter solstice 2.png]] | |||
[[File:Summer diagram.png|240px]] | |||
[[File:Winter diagram.png|240px]] | |||
Latest revision as of 14:13, 17 September 2010
Do all observers see the sun at the same location at dawn?
Pretty nearly. It doesn't vary as much as I predicted from drawing 2 dimensional pictures of the 3 dimensional reality.
I collected these charts and tables on 11 September 2010, which is close to the fall equinox. At dawn, someone near Buffalo would see the sun at 83.1 degrees, which would generate LOP perpendicular to the sun sighting of 353-173. The sunrise azimuth at Howland would be 85.59 and 85.65 at Niku, giving a LOP of 355-175.
I don't know whether the difference is due to the earth not being a perfect sphere or solely to the difference in the latitude of the observers.
Source: www.sunearthtools.com - Sun position calculator:
Howland
| Latitude | 0.80108 |
| Longitude | 176.61624 |
| Sunrise Azimuth | 85.59 |
Niku
| Latitude | 4.67792 |
| Longitude | 174.5196 |
| Sunrise Azimuth | 85.65 |
Near Buffalo
| Latitude | 42.57264 |
| Longitude | 78.82926 |
| Sunrise Azimuth | 83.1 |
Gallery
