Planet s Visibility description
Planetary, Lunar, and Stellar Visibility - shows a 3-color diagram that shows when a planet, the moon or the sun is visible

Planetary, Lunar, and Stellar Visibility is an interesting program that presents a 3-color diagram that shows when a planet, a star, the moon or the sun is visible during any year from 3000 BC to AD 6000 at any location on the earth. The vertical axis marks the months of the year, the horizontal axis marks the hours of the day.

The three colors create a contour map effect and show whether the body is under the horizon (black) and invisible, above the horizon with the sun (light color) and invisible, above the horizon without the sun (shaded color) and so possibly visible.

The times of sunrise and sunset and when the sun reaches specified altitudes above or below the horizon can be shown as curves on the diagrams. By moving the mouse over the diagram, the date and time along with the object's altitude, azimuth, and magnitude, or the phase of the moon, are displayed.

In addition, Planetary, Lunar, and Stellar Visibility computes and tabulates the dates of visibility phenomena: for planets and stars first and last visibility, acronychal rising and cosmical setting; for the moon first and last visibility, and the tables provide much supplementary information.

These phenomena are very useful for historical purposes. Since the computation of visibility phenomena is complex and uncertain, alternate methods are provided and parameters can be altered by the user to find what appear to be the best results.

There are also diagrams of solar and lunar eclipses, of the rotation, inclination, illumination, and apparent size of the bodies, and of Jupiter's satellites. The settings for the computations may be saved, the graphics may be saved, pasted into documents, and printed, and the tables for visibility phenomena may be accumulated, edited, printed, and saved as .rtf files or HTML files to be pasted into documents and printed.

provides:

visibility diagrams for the sun, moon, planets, and stars
dates of heliacal phenomena of planets and stars
dates of first and last visibility of the moon
.rtf files of all information for visibility phenomena
HTML files of times of rising, culmination, and setting of the sun and the moon, planet or star, with differences, for each day of the year
HTML files of all information for visibility phenomena for up to 100 years
documentation, which explains the program, methods of computation, and user modifications

Here are some key features of "Planet s Visibility":

· calculates for any year at intervals of 4 minutes:
· horizon coordinats of the sun, moon, planets, and stars
· magnitudes of the planets
· phases of the moon
· shows all of these corresponding to the position of the mouse cursor in the diagram
· includes a database of observer locations with more than 400 entries user may add any number of locations
· marks the local time in the diagram for current year and location
· year of computation accepted from 3000 BC to 6000 AD
· shows visibility conditions, whether visible or invisible by colors and variation of apparent magnitude by shadings, from light when the planet is brighter to dark when fainter (if the computer’s color resolution is 15 bpp. or better, meaning “high color” or “true color”)
· shows the times of twilight in diagram for the sun
· shows the times of sunrise and sunset and times the sun is at specified altitudes above or below the horizon
· uses Daylight Savings Time if selected
· calculates the dates of heliacal phenomena of planets and stars and marks them in the diagrams as horizontal lines with vertical lines showing times of planet rise/set and sun rise/set
· user may select parameters for these computations
· calculates the dates of first and last visibility of the moon and marks them in the diagram as horizontal lines with vertical lines showing times of moon rise/set and sun rise/set
· user may select parameters for these computations
· shows the times of solar and lunar eclipses visible from selected location and local circumstances of the eclipses (accurate for historical eclipses e.g. the "historical" total solar eclipse of 899 BC) in separate windows
· shows the shows the positions of the Galilean satellites of Jupiter
· shows rotation and illumination diagrams for the planets, the moon and sun