Looking Up: Catch a passing satellite tonight
More Content Now One of the pleasures of star watching in the space age is the watching of manmade satellites as they cross the sky. If you gaze at the starry sky, it likely won’t take long before you are notice a “star” moving past stars and through whole constellations. Here awesome pointers.
Satellites are launched towards the east to benefit from the centrifugal force as the Earth also spins towards the east. That means while looking up you generally see satellites traveling west to east; you won’t see them going the opposite way.
Many satellites, however, are put in polar orbits, either north to south or the other way around; some may be traveling southwest to northeast, or northwest to southeast.
They appear as single points of light, without color. If you see something with red, green and white lights, it’s a jet! You may be surprised at how many of them you well see as well, especially if you live under a flight path between major airports. They go in all sorts of directions.
Most satellites you see with unaided eyes are moderately bright, about +2nd or +3rd magnitude, or dimmer. A very few are very bright, including the International Space Station (ISS).
(Note: Star brightness is ranked on a scale of magnitude; the lower the number the brighter it is. The faintest star you can see with unaided eyes under excellent conditions is +7. Brilliant planet Venus, see in the southwest after sunset this winter, shines at about - 4.)
Very interesting about satellites is that you will notice how they quickly fade and disappear altogether. This happens when the satellite, in its orbit, plunges into the Earth’s shadow. In the evening hours, the cone-shaped shadow is covering much of the eastern sky, although you won’t detect it unless it covers up a satellite!
Because of the rotating Earth, at midnight you are on the side of the planet where the shadow is covering the southern sky. Depending on how high the satellite is orbiting, you would only see it low in near the horizon where it is not in the shadow.
Sometimes you see very unusual satellites.
You might see one that fades in and out in brightness, at regular intervals. This is typically a spent rocket stage, which is tumbling.
On a rare occasion you may see a couple satellites at the same time, a few degrees apart and flying in tandem, on some special mission.
If you observe with a telescope, you will see many more satellites much too faint to be seen by unaided eyes. With magnification, they tend to pass by quickly in the telescope’s field of view.
The ISS is always very interesting, as you ponder that “bright star” moving along has people aboard. One time I caught it in a telescope and was able to make out some of its actual shape. Be sure to wave.
This past Christmas night, December 25, under a very starry sky, I witnessed an unusual satellite. I glanced at the constellation Orion, and was amazed to see that the three stars of the “Belt” were accompanied by what appeared to be another star of similar brightness, a little out of line with the three! This “new star” did not seem to be moving at all!
I was very startled, wondering if a nova had occurred- a real star normally too dim to see with eyes alone, that suddenly flared in brightness. Bright ones are extremely rare. I grabbed a pair of large binoculars and found that this “new star” was very slowly moving to the east, past faint stars- it was a satellite.
This extremely slow satellite started to fade, and disappeared in the Earth’s shadow.
To be moving so slow, the satellite had to be very distant; to be as bright as it was, and so far, is also unusual.
A search online did not reveal any information. Did anyone reading this column witness it too? I would love to hear from you.
To find out when the space station is passing overhead, visit the NASA web site at https://spotthestation.nasa.gov/.
Full Moon is on January 12.
Keep looking up!
Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at firstname.lastname@example.org. Please mention in what newspaper or web site you read this column.