Analyse de l'application Perpetual Nautical Almanac pour le 21 décembre

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.