Why do some satelites have lights?

I'm sure the answer will be obvious once explained, but with out a scope and star program I'm not sure what I'm looking at every May thru Aug. It sits about 30 degrees above the horizon about nnw from my location. It looks like a star in the 5-6 mag range but emits red,blue and green lights. I'm not sure if it a star or satelite and if it is a satelite, why the lights?

If its a satellite, maybe the put lights on it so one can see it. If I would think space would be dark. Except when your by a planet or a star. If they need to repair the satellite. It would be useful if the they had lights on it so they could see to work with, and so that they could find it in space. But I also have no idea what i'm talking about either.

Sounds like you are looking at a star. At 30 degrees, depending on your location, you are probably getting a good amount of atmospheric distortion.

Do a search a read up on it a little if you aren't familiar; it's actually pretty cool. The red, blue, green is the light from the star getting distorted to different wavelengths.

Hope that helps.

Cool. Thanks for the info. Any ideas why satelites would need lights?

I remember a couple decades ago one of my friends bought a brand new Meade telescope with a ten inch mirror. He read the manual and familiarized himself with the polar alilgnment procedures, then we headed to the outskirts of town to see the stars. Consulting the star atlas we decided to find the ring nebula. ( We dubbed the procedure of zeroing in on celestial objects by dialing in your Right Ascension and Declination as "doing the universe by numbers".) We got the scope dialed in and my friend looked through the scope. He said "Wow this is way brighter than I ever imagined." Then he goes "Wait it went off, now it's back on again, now it's off." Turned out the scope was close enough to the horizon that we were looking at the out of focus light on top of a tower.

Sounds like an airplane to me...

Sattelites don't have any blinking lights, at least ones that can be visible from the ground. Think about how bright those lighst would have to be in order to been seen on the ground when it's 100+ miles up.

If it's a star, then it would follow all the other stars in the sky and rise and set. You said it's 30 degrees up in the NNW, but what is your location? With that info I can look up what bright stars are in that region throughout the night.

Fairly close to you. Port Washington, Wisconsin. 30 miles north of Milwaukee. BTW this thing does move very slowly. I can see it from just about dusk 9:00 pm central thru 11:00 pm when it dips below my line of sight.

As it moves is it following the other stars in the sky? I'm guessing you're seeing either Venus or Capella as they set.

i was always under the impression that if it blinks red, green, blue, then its a satalite (not because it has lights, but because of the light from the sun reflecting off of it).....

i've noticed that most blinking, (red, green, blue) objects in the sky that i have seen tend to bemoving...(and no, not as fast as a plane...lol), so i just assumed the stationary ones were satalites in a geo-synchronous orbit...


EDIT: to add: i could be totally wrong here by the way....

[edit on 7-6-2005 by Urn]

I'm going with cmdrkeenkid on this one.
Venus, is the "evening star" right now.
Besides, lights on a satellite, would be a terrible waste of energy.
Low horison objects have a lot of atmosphere to shine through, due to the angle. Makes them subject to distortion..as others have said..

I'm pretty sure that's it's not venus. I can see her almost directly overhead from my position.

I agree, it seems wastful to illuminate a satellite.

If the Sun's light were reflecting off of it, then it would appear to be yellow in color.



Probably were planes, because a plane at cruise altitude appears to be moving at the same speed as a satellite. Think of it this way... A plane is moving at 500 miles/hour, at 35,000 feet. A satellite is moving at 5 miles/second, but it's at 120 miles. The sheer distance makes them appear to be moving at about the same price.

Geosynchronous satellites are over the equator and are also about 20,000 miles up. There's no way they can be seen.

Okay, so it went from 30 degrees in the NNW to directly overhead now? Which is it?

I was making reference to venus being overhead...indicating that my bogie and venus were definetly not one and the same.

Erm... Maybe Venus is only overhead right now because the Sun is nearly ovehead right now. But at around 9:00 at night, it's about where 30 degrees up and in the NNW.

I may be mistaken, but "during the evening" I thought the extremely bright object was venus (overhead) as opposed to the flickering star/satellite 30 degrees NNW.

Still, does anyone know if they illuminate satellites and if so what for?

Venus isn't overhead at that time, in your location. Take a look here...



Whatever is overhead is more than likely Jupiter.

Cool, thats about where it shows. Any idea why it flickers blue red and green as opposed to an orange Jupiture?

I havent noticed Jupitor getting colorful much this year but Saturn has definitely been showing off. By your descriptions my money is on Saturn.

And I dont remember where I read it, but I think I remember that some/most satellites do have some form of illumination, only it is off until remotely activated to aid in locating for repair.