Perpetual Nautical Almanac app for iPhone and iPad

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.