Two Internet Satellite Services will be used in this project:
Satellite passages last only a few minutes. Therefore, you must first set your computer clock time as accurate as possible (say within 2-3 seconds):
ITS - Internet Time Service software can be used to automatically set you computer clock. It can be downloaded from NIST
Your world location (Latitude and Longitude) must also be determined. My web page is set up for Taos, New Mexico ( Lat = 36.4070N, Long = 105.5730W ). You can set your own latitude and longitude by:
- If you are new at this .. I suggest that you keep it simple and start by looking for the brightest satellites (such as the ISS, International Space Station satellite and the HST, Hubble Space Telescope satellite) until you are familiar with this process. Predictions and star maps of either the ISS or HST .. and other bright satellites .. can be obtained by clicking on one of the selections within the "Satellite Paragraph" of the Main Page of the "Heaven Above" service.
- Before you can use the "Heaven Above" service .. you must first enter your location.
- The "Heaven Above" service has many useful options that go beyond satellite predictions. I recommend that you become familiar with some of the available options.
- Given your location and time, the predictions will be very accurate.
- The use of star maps showing the time-position of a satellite as it crosses the night sky can be invaluable in checking your set up: observing procedure, time and location.
- Remember that satellites can pass into the Earth's shadow and therefore will not be seen when this happens. Star charts obtained from the "Heavens Above" service will show the time of this event. Generally, local midnight is not a good time to look for near orbiting satellites.
- The angular speed of a satellite as it crosses the night sky is somewhat similar to that of a jet aircraft .. and both may appear as points of light .. but there are differences in the way they look:
- A jet have two colored lights that sharply blink on and off .. about a second apart. Satellites may or may not tumble. If they do then they will slowly appear to get dimmer then brighter depending on their rate of tumble.
- You will never "hear" a satellite. Normally, you will hear jet noise arrive much later and in a direction following the current position of the jet in the night sky.
- Jet fly from horizon-point to horizon-point .. satellites can suddenly disappear .. if they enter the Earth's shadow.
- By all means .. experiment with the various options you'll find at these two services.
- J-Track provides a real time view of the locations of thousand of satellites. It can be used to help identify an "unknown satellite" which has just been observed at your location.
- Your computer must allow java-animation
- It will take several seconds for the satellite data base to load. However, once loaded rotate the globe (by dragging the cursor across the image) until your world location is in the middle of the image.
- If necessary .. zoom in on the image
- Watch the satellite points for a few seconds. Their movements will show you the general direction of motion of each point and this will help you identify your "unknown satellite."
- To identify any of the satellites .. near you .. select a point and click on it. It's name will pop up. Use this name (exactly as is) in the "Heavens Above" satellite service to obtain more detailed information about your "unknown satellite"
- Using the "Select a satellite from the database" option of the Satellite paragraph of the Main Page .. and enter the name that you just obtained from J-Track
- click through to the next page
- Using one of the options: "passes" or "orbit" obtain further information about the "unknown satellite" .. such as pass predictions and star maps
- If you click to the "Whole Sky Chart" which shows a star map of the whole sky within a circle .. it may, at first, appear reversed to you. This is not an error ! The following explanation is given:
Whole Sky Chart
This chart show the path of the satellite across the sky. Please note that East and West are NOT the "wrong way round" if you hold the chart over your head to correspond to the view of the sky.
To set the star chart correctly, hold the chart over your head .. with North pointing toward the North star (Polaris).
I prefer the more detailed star chart that appear down this page, anyway.