Perpetual Nautical Almanac analisi dell'app per 21 dicembre

Using the U.S. Naval Observatory NOVAS library and solar system ephemerides from JPL, high precision positions can be calculated in real-time from 1900 to 2050. Simply select date and time and all values are recalculated instantly. The estimated elevation value is only needed for calculating sunrise/sunset, twilight, and moonrise/moonset. The app provides the following functionalities: *Aries: GHA position *Sun: -GHA/dec - Astronomical dawn, nautical dawn, civil dawn, sunrise, sunset, civil dusk, nautical dusk, astronomical dusk, and meridian passage at Greenwich. - Semidiameter - Sunlight world map with the Sun and the Moon position. *Moon: - GHA/dec - Moonrise/moonset and meridian passage at Greenwich. - Semidiameter - Moon phase and age of the Moon. *Planets: - GHA/dec for Venus, Mars, Jupiter, and Saturn. *Stars: - Magnitude, SHA/dec of 99 stars ordered by SHA. *Corrections: - Correction for the atmospheric refraction. - Correction for the dip of the horizon. - Parallax correction for the Moon, the Sun, Venus, and Mars.