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GeoAstro Applets

Astronomy

Chaos Game

Java

Miscel- laneous

Physics Quiz

Who is Who ?

	Check your time zone offset and your local time ! value derived from longitude:
	Enter latitude in decimal degrees and press return key, enter longitude in decimal degrees and press return key, or use the Locations menu.
	The View menu provides six views: 1. a Diagram showing the rise and set times over the year, 3 different representations 2. a view at local the Horizon (rectangular coordinates), 3. a view at local the Horizon (spherical projection), 4. a view at local the Horizon (polar coordinates), 5. a view of the Ecliptic plane, 6. a view of the orbit of the Moon around the Earth, 7. a Sky Map view, 8. an Earth Map view.
	Use the Planets, Moon menu items to show or hide the planets and the Moon.
	The items of the Details menu, working in toggle mode, show and hide additional details. "Horizon Image" changes the background image of the Horizon View.
	You may use the keys y, m, w, d, h, n to increase the yaer, month, week,date, hour, or minute, or Shift key and y, m, w, d, h, n to decrease the year, month, week,date, hour, or minute. Use c or shift key and c to increase/decrease the century.
	Choose from the Write/Draw ... menu to write data to a new window (rise and set or position data of the Sun, Moon and Planets).
	You may enter your home location by editing the applet parameters of this HTML page. Details here.

In case the applet is not running, click here

Books

Planetary events to discover and to explore

1. Select "Diagram" from the View menu:

Redrawing the diagram will take some time because of 365 complex computations have to be done.

To draw rise and set of a single planet select "None" from the Planets, Moon menu
and then turn on the planet to show.

Example: Berlin, 2004 March 20:

Rise   Set

There are three different representations of the diagram:

To hide or show the current sun in the Diagram View choose "Sun" from the "Details" menu.

To show the visibility of a planet select "None" from the "Planets,Moon" menu,
and than the planet.

2004: Venus visible as Evening Star (upper green regions)
or Morning Star (lower regions)

2004: Visibility of Mercury

The duration of the Astronomical Night (Sun more than 18° below the horizon) and the Local Mean Sidereal Time are indicated.

2. Select "Horizon Rectang." from the View menu:

This equirectangular projection is a cylindrical equidistant projection,
in which the horizontal coordinate is the longitude and the vertical coordinate is the latitude. (x=λ, y=φ, equator as standard parallel).
Extreme distortions near the poles.

To draw the diurnal path of the Sun select "Show Orbits" from the "Planets, Moon" menu.

3. Select "Horizon Spher." from the View menu:

Projection details

	You may use the keys m, w, d, h, n to increase the month, week, date, hour, or minute or Shift key and m, w, d, h, n to decrease the month, week, date, hour, or minute !
	Use the Planets, Moon menu items to show or hide the planets and the Moon.
	Click a celestial body to read its azimuth and elevation.
	The items of the Details menu, working in toggle mode, show and hide additional details (if applicable). "Horizon Image" changes the background image of the Horizon View. The brightest stars
	magnitudes of planets
	Altitude (Elevation) Azimuth
	Right Ascension Declination The first equatorial coordinate of a star (St) is the declination delta, measured in degrees north and south of the celestial equator (N: 0° < delta < 90°, S: 0° > delta > - 90°. The second coordinate is the Right Ascension RA, measured along the equator from from a zero point known as the vernal equinox (V).	A screen shot of Walter Fendts applet Apparent Movement of a Star
	Sun elevation > 0° -6° < elevation < 0° -12° < elevation < -6° -12° < elevation < -18° elevation < -18°	civil twilight nautical twilight astronomical twilight
	The Julian Day and the Local Mean Sidereal Time are indicated.
		Select "Sun" from "Choose Details" to see the path of the Sun, and the intersection angle with the horizon (alpha). By this angle the time interval for rise and set is computed (in minutes): 4*sunDiameter/sin(alpha)

4. Select "Horizon Polar" from the View menu:

or "Horizon Pol. Zoom":

you may choose details:

To draw the diurnal path of the Sun select "Show Orbits" from the "Planets, Moon" menu.

The brightest stars

5. Select "Ecliptic" from the View menu:

(from above the solar north pole)

or Select "Ecliptic Zoom":

(not showing Jupiter and Saturn)

	Ascending node, the point where the planet crosses the ecliptic from south to north. Perihelion (Perigee), the point of closest approach to the Sun. Aphelion (Apogee), the point furthest from the Sun.
	The Earth-Moon distance is magnified by 25. The red line is the Greenwich meridian.
	Use the keys commands h, d, w, m to increase the hour, date, or month, to observe retrograde motion.
	Use the "Planets, Moon" menu to show or hide the Earth-Planet lines and the orbits.
	For Mercury and Venus the current elongation angle from the Sun is displayed. An eastern elongation angle means Mercury will be visible in the western sky after sunset, while for a western elongation Mercury is visible in the eastern sky before dawn. The opposition or conjunction of a planet is indicated in case the proper month and date is selected.
	The planet is above the ecliptic plane (heliocentric latitude is positive). The planet is below the ecliptic plane (heliocentric latitude is negative)

6. Select "Ecl. Earth/Moon" from the View menu:

To switch off the lines choose "Hide Lines" from the "Planets, Moon" menu.

Watch the retrograde rotation of the (green) line of nodes (the mean longitude decreases by about 19° per year),
and the prograde rotation of the (blue) line of perigee (the mean longitude increases by about 41° per year).

Perigee and Apogee distances

Lunar Perigee and Apogee Calculator

Applet: Computing the motion of the Moon

7. Select "Sky Map" from the View menu:

	The phases of the Moon
	The ascending node of the Moon is indicated (grey oval). Choosing "Show Path" from the "Choose Details" menu will draw the positions of the Moon for the current month and of the planets around the current date: +/-45 days for Mercury, Venus, +/- 90 days for Mars, Jupiter, +/- 120 days for Saturn. The example is showing a loop of Mars (retrograde motion).
	Click the sky map to show the coordinates.
	Command key and click will draw a green cross mark. These coordinates (RA and decl.) are indicated in the "Horizon Rectang.", in the "Horizon Polar", and in the "Horizon Spher." view:

or choose:

The brightest stars

Use "Stars and Names" from the Details menu to show or hide star names.

Click a star to show its name and magnitude:

8. Select "Earth Map" from the View menu:

Use the Details menu to add more details (stars, bright planets, etc.):

A celestial bodies (star, planet) is seen at the zenith by an observer
located at the position of the body on the world map
(declination=latitude, hour angle=longitude).

Click the map to get the location, or the latitude and longitude

Select "Altitudes Sun" from the details menu to draw lines of equal Sun altitudes

Data and Graphics windows:

Choose from the Write/Draw ... menu

	Draw Geocentric Motion
	Draw Opposition Loop
	Draw Equation of Time
	Draw Planet Phases	Draw diagrams:
	Mercury Phases Venus Phases	Create a table of the dates of conjunctions and phases.
	New Moon Full Moon	Dates of New Moon and Full Moon for the year selected, and lunations. Synodic Month
	Local Full Moon	Local Full Moon Transit Elevation (diagram)
	Moon Nodes	Dates and times of the node passages of the Moon. Draconic Month
	Moon Perigees Moon Apogees	Dates and times of the perigees or apogee of the Moon. Anomalistic Month
	Moon Latitude	Extreme ecliptic latitudes of the Moon (diagram)
	Moon Alt/Az/Phase	Altitude, azimuth and illuminated fraction of the Moon for any day of the month selected (1 hour interval).
	Moon Declin	Extreme declinations of the Moon (diagram)
	Data Sun, Moon	The window "Data Sun and Moon" : - the date and time of solstices, equinoxes, perihelion and aphelion for the current year. - the date and time of New and Full Moon for the current month (UT is accurate within +/-1 hour). - the date and time of the Moon's perigee and apogee for the current month. The hours (UT) are accurate within +/-1 hour).
	Morning Twilight Evening Twilight	Table showing the begin (end) of nautical and civil twilight (depression 6°), the sunrise (sunset), and the duration of civil and nautical twilight.
	Equation of Time	List of the Equation of Time (at 12 UT) and the daily change. The mean error is less than 1 second.
	Data Planets	Perigee, Apogee node passages (ascending, descending).
	Groupings	Planetary separations (in geocentric longitude) of less than 5° (or 10°, or 3° when opened again) taking place more than 10° from the Sun.
	Opp./Conj./Elong.	Opposition, conjunction, max. Elongations of Mercury and Venus.
	Eclipses	Lunar Eclipses: looking for Full Moon (difference of geocentric longitudes 180°, opposition) and ecliptic latitude <+/-1.5° Solar Eclipses: looking for New Moon (difference of geocentric longitudes 0°, conjunction) and ecliptic latitude <+/-1.5°
	Star List	The brightest stars (mag<2), and their rise, transit, and set time.
	Location List	The locations available from the Location menu.
	Sun Month	Sunrise and sunset, civil, nautical, and astronomical twilight, daylight hours.
	Sun Year	Sunrise and sunset, civil, nautical, and astronomical twilight, daylight hours details about daylight hours, latest sunrise, and earliest sunset.
	Sun & Plan Month Sun & Plan Yr	Sunrise and sunset, civil, nautical, and astronomical twilight, daylight hours, rise and set of the planets and the Moon.
	Ephemer. Mth	Positions at 0:00 UT: Apparent Heliocentric Position: longitude, latitude, distance. Apparent Geocentric Positions (True Equinox and Ecliptic of Date) Ecliptic System: longitude, latitude, and Equator System: right ascension, declination, distance, errors: longitude +/- 0.01°, latitude +/- 0.001°. Compare with MICA (Multiyear Interactive Computer Almanac, U.S. Naval Observatory)
	Zodiac	the Position of the Sun, Moon and planets
	Sun Alt & Azim Day Sun Alt & Azim Hr	Altitude and azimuth of the sun for the date selected.
	Moon Alt & Azim Day	Altitude and azimuth of the Moon for the date selected.
	Moon Trans. Alt Year	Altitude of the Moon at transit for the location and year selected. (diagram)

Geocentric Motion:

Opposition Loop:

Details for the opposition loops of Mars

Retrograde motion is occurring for the outer planets at their opposition,
and for the inner planets at inferior conjunction.

Equation of Time:

Planetary Phenomena
Eclipse Home Page (Fred Espenak)
 

APPLET Parameters:

You may enter your home location and change some settings by editing the applet parameters of the HTML page.
Open "index.html" in Netscape's Composer, in any HTML editor or in Windows' editor.

<APPLET CODE="planets113.class" WIDTH=780 HEIGHT=580 ALIGN=bottom archive="applet/JavaClasses.jar"> <PARAM NAME=password VALUE=........> <PARAM NAME=email VALUE=...........>	Do not change.
<PARAM NAME=location VALUE="Berlin"> <PARAM NAME=latitude VALUE="52.51"> <PARAM NAME=longitude VALUE="13.41">	Edit the text of the location parameter, and the values of the latitude and longitude parameters (decimal degrees). Enter southern latitude and western longitudes with a minus sign !
<PARAM NAME=background VALUE=0>	Set the background parameter value to 1 in case you prefer a light grey applet background
<PARAM NAME=image VALUE=sunview>	Change the image parameter value to sunview1 to change the horizon view background image. Preview: sunview, sunview1
<PARAM NAME=startview VALUE=2>	Set the startview parameter value to 1 to start by the Rise and Set diagram, 2 to start by the Horizon (rectangular coordinates), 3 to start by the Horizon (spherical projection).
</APPLET>

© 2003-2014 J. Giesen