File:Analema Terrestre y Marciano.png
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Summary
| Description |
Español: Un analema o lemníscata solar es la curva en forma de ocho que traza el Sol en el cielo diurno a lo largo de todo el año, es decir todos los días y a una misma hora va cambiando su posición en el cielo. Fijando una cámara a un trípode y cada 10 días sobreexponer cada foto para “graficar” tal curva.
Sus diferentes formas se deben a la inclinación del eje del planeta respecto al plano de su órbita y a la excentricidad orbital en sí. Aquí la marciana (no es una lemníscata, es otra curva) es mas “ancha” dado que la excentricidad del planeta rojo es mayor que la terrestre y un poco más “alta” debido a que la inclinación de su eje con respecto a su plano orbital también es mayor que el de la Tierra. Esta inclinación se la denomina “Oblicuidad de la Eclíptica”. Si en alguno de los dos planetas su órbita fuese un círculo y su inclinación nula, todos los días a la misma hora se lo observaría en el mismo punto del cielo diurno, no habría ni curva ni lemníscata. Si fuese su órbita un círculo y su inclinación distinta de cero, se dibujaría a lo largo del año una línea vertical coincidente con la línea meridiana.English: An analemma or solar lemniscate is the curve in the shape of a figure-eight that traces the Sun in the daytime sky throughout the year (each day at the same time as it slowly changes its position in the sky). Fixing a camera to a tripod and every 10 days multiply-exposing a photo allows one to "graph" such a curve.
Different forms of the curve arise due to the inclination of the planet's axis with respect to the plane of its orbit and the orbital eccentricity itself. Here the Martian analemma (it is not a lemniscate, but another curve) is wider since the eccentricity of the red planet is greater than the terrestrial one and a little higher above the horizon because the inclination of its axis with respect to its plane Orbital is also greater than that of Earth. This inclination is called "obliquity of the ecliptic". If one of the two planets had an orbit that was a circle and its inclination level, every day at the same time it would be observed in the same point of the sky; neither a lemniscate nor any other curve would be observed. If the orbit were circular but the inclination off-level, a vertical line coinciding with the meridian line would be drawn throughout the year. |
| Date | |
| Source | Own work |
| Author | Fernando de Gorocica |
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 20:54, 4 May 2014 | | 1,186 × 752 (744 KB) | Fernando de Gorocica | User created page with UploadWizard |
