I'm using the heavens-above website to identify a satellite I've seen several nights this week.

The question is related to how I can search the satellites table with the information I can provide.

The page has a table that has the satellite name, Brightness (mag), and Time, Altitude, and Azimuth for Start , Highest point and End. I don't know how brightness and altitude are measured, and I don't know how the start, highest, and end points are measured. In terms of azimuth, if I base it on this compass, and based on the time I saw it, I would have to say NNE.

With that said, last night I was sitting looking straight north. I first saw the satellite, literally moving directly over my head, at 7:33pm EST and stopped seeing it at a 7:36PM EST because it was too far. The satellite was going North and just a bit to the East.

My question: how can I use this information to search for the satellite in the table? Also, how do I know what's the Brightness (mag)? The satellite is so tiny that it's almost impossible to see with the naked eye.


1 Answer 1


Altitude is measured in degrees above the horizon, from 0° on the horizon to 90° directly overhead. Your fist appears about 10° wide at arm's length away from your eye.

Azimuth is measured along the horizon, usually with north 0°, east 90°, south 180° west 270°, and other directions (e.g. NNE, ENE) interpolated as in the compass image.

Magnitude is a logarithmic scale in which the brightest stars are 0 or 1, and the faintest stars visible to the unaided eye are 4 or 5 (maybe 2 or 3 in a city, or 6 in a remote area).

Each row of Heavens-Above's table links to a sky chart showing their predicted path for that satellite pass. The brightness listed in the main table is a maximum; the table under the sky chart shows a brightness for other points on the path.


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