|
|
| Line 1: |
Line 1: |
| A '''square degree''' is a non-[[SI]] [[Units of measurement|unit]] measure of [[solid angle]]. It is denoted in various ways, including '''deg<sup>2</sup>''', '''sq.deg.''', (°)², and ☐°. Just as [[degree (angle)|degree]]s are used to measure parts of a circle, square degrees are used to measure parts of a [[sphere]]. Analogous to one degree being equal to ''π'' /180 radians, a square degree is equal to (''π'' /180)<sup>2</sup>, or about 1/3283 or 3.0462{{e|-4}} [[steradian]] (0.30462 msr). The number of square degrees in a whole sphere is
| | The title of the writer is Figures. For many years he's been operating as a meter reader and it's something he really appreciate. California is our beginning place. It's not a common thing but what she likes performing is foundation leaping and now she is attempting to make cash with it.<br><br>My blog - [http://moodle.kspu.karelia.ru/user/view.php?id=23302&course=1 moodle.kspu.karelia.ru] |
| | |
| : <math>4 \pi \left(\frac{180}{\pi}\right)^2 = \frac{129\,600}{\pi},</math>
| |
| | |
| or approximately 41 253 deg<sup>2</sup>. This is the total area of the 88 constellations in the [[list of constellations by area]]. The largest constellation, [[Hydra (constellation)|Hydra]] covers a solid angle of 1303 deg<sup>2</sup>, whereas the smallest, [[Crux]] covers 68 deg<sup>2</sup>.<ref>[http://calgary.rasc.ca/constellation.htm#list RASC Calgary Centre - The Constellations]</ref>
| |
| | |
| For example, observed from the surface of the [[Earth]], the [[sun]] or the [[Moon|full moon]] has a diameter of approximately 0.5°, so it covers a solid angle of approximately 0.2 deg<sup>2</sup> (≈ ''π'' ({{sfrac|0.5|2}})<sup>2</sup> deg<sup>2</sup>), which is 4.8 × 10<sup>−6</sup> of the total sky sphere.
| |
| | |
| Assuming the Earth to be a sphere with a surface area of 510 000 000 km<sup>2</sup>, the area of [[Northern Ireland]], 13 600 km<sup>2</sup> represents a solid angle of 1.10 deg<sup>2</sup>.<ref>[http://www.ons.gov.uk/ons/rel/regional-trends/region-and-country-profiles/key-statistics-and-profiles---august-2012/key-statistics---northern-ireland--august-2012.html Country Profiles: Key Statistics - Northern Ireland, August 2012]</ref> Similarly, the area of [[Connecticut]], 14 356 km<sup>2</sup> represents a solid angle of 1.16 deg<sup>2</sup>.<ref>[http://m.usembassy.gov/67133/show/48cfb5952231d07616e065c4e972a2b4&t=3854e8b8732893e84a65c8b81e3312c1 The 50 States | Embassies & Consulates Directory]</ref>
| |
| | |
| ==References== | |
| <References/>
| |
| | |
| ==External links==
| |
| * http://calgary.rasc.ca/constellation.htm#square
| |
| | |
| {{DEFAULTSORT:Square Degree}}
| |
| [[Category:Units of angle]]
| |
Latest revision as of 21:59, 30 October 2014
The title of the writer is Figures. For many years he's been operating as a meter reader and it's something he really appreciate. California is our beginning place. It's not a common thing but what she likes performing is foundation leaping and now she is attempting to make cash with it.
My blog - moodle.kspu.karelia.ru