Quick question...

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mojo519

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My wife and I have both been noticing something bizarre for the past several months. It is a solid light (not an airplane) which moves either West to East, North to South, or occasionally South to North across the sky every night. The brightness varies, sometimes rapidly. I watched one tonight move North to South and rapidly dim as it did so. It started out fairly bright, but as it moved it seemed to disappear completely within maybe 5 seconds. They almost always appear 1 at a time, although we did see 2 fairly close together a couple of nights ago following the same path with 1 behind the other.

My guess is that these are satellites. They appear in roughly the same place every night and follow very straight paths. Except for the ones that grow dim, they are consistent in location and path of travel, and move in precise compass directions. I'm guessing that the dimming effect is probably due to either high level clouds, or possibly a change in elevation so that the Earth blocks them from reflecting the Sun's rays.

With that said, I'm hoping for an expert's opinion. Are they satellites, and am I correct in my theory as to the dimming?
 
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MeteorWayne

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Welcome to Space.com!

Yes they are satellites. There are dozens visible every night. They range in brightness from the ISS which is brighter than any planet except Venus when nearly overhead, to many faint enough you need binoculars to see the.

And you are correct, particulary for the ones in lower orbits like the ISS, they can pass into the earth's shadow and fade out, or even appear from the earths shadow and fade up.

There are also other spectacular ones called Iridium flares which cause a chort (5-10 second) flare than can be many times brighter than Venus.

There are some that vary smoothly in brightness, and some that flash at both regular and irregular intervals.

To learn more and be able to get predictions of when they will be visible (It shows most of the brighter ones) see

http://heavens-above.com

Select your location, THEN save the page.

Meteor Wayne
 
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