This applet shows the locations of the planets, stars, moon,
and sun in the sky from any location and for any date and
time. This applet does not run under some browsers in some
versions of MacOS. For more information, see the author's notes on Java
Cleveland, OH is Latitude 41n / Longitute 81w (you'll need to click w)
- The program needs to know your location in order to predict what the sky will look like. Initially, it just guesses the biggest city in your time zone. If this is incorrect, you can set your location either by typing in your latitude and longitude or by choosing a city from the list (which only includes those with populations greater than 3 million).
- Use 24-hour time for setting the time, e.g. 13:00 means 1 pm.
- In the U.S., daylight savings time lasts from 2 am on the first sunday of April until 2 am on the last sunday of October. The program handles this by default. If you are not in the U.S., you may need to set daylight savings time manually.
- The compass directions may look wrong, but that it because the screen represents the way the sky looks when you look straight up. The compass directions are therefore a mirror image of the compass directions on a map, which represents a view of the land looking down from above.
- The spherical sky has to be projected onto the flat screen. This projection produces distortion, just as a map of the earth inevitably has some distortion. The greatest distortion occurs near the horizon.
- The disks of the sun, moon, and planets are not drawn to scale. Their brightnesses are given as magnitudes to the right of their names. A more negative magnitude means a brighter planet. The magnitudes given for Saturn do not include the brightness of the rings, so Saturn will usually be brighter than indicated.
- This program is only designed to have a limited degree of accuracy, sufficient for most naked- eye astronomy applications.
See the original