Lasers

[Xaelzc]

What is the likelihood of seeing much more activity in the night sky, be it satellites, shooting stars, falling stars after pointing at certain things with a green laser? I see shooting stars every time I point with a laser in the direction that I am pointing, and not just one at a time, it could be space junk or actual shooting stars or other space vehicles. Main question: When I use a laser at night I see lights moving, can't tell if its satellites or not and would like to know what a jet dropping flares looks like from below. The lights that I see are moving much lower than a satellite and not all of them blink light, some blink maybe once or twice in my line of sight then are gone. What types of satellites fly low enough to be seen and suspected of being jet with no sound or "something else"?

 

[MeteorWayne]

Lasers have nothing to do with causing anything to happen in the sky.

At night, there's no way to tell how low a point of light is.

Many satellites flash a few times and are invisible in between.

Lightning bugs also flash occasionally.

 

[Xaelzc]

I was wondering if there are low orbit satellites that can be mistaken for something else. Distance can't be judged at night, but size is comparable no matter what. If a moving light (not blinking) was to be much lower and larger than a plane flying over there is a very obvious difference between a plane with flashing lights, with a jetstream behind it (very clear lights, and sound behind the plane) while a low flying light has no jetstream, and flies silent with a constant light.
Would there be a reason why I would see more than 3-7 satellites pass over the same area in one night?

 

[a_lost_packet_]

What is the likelihood of seeing much more activity in the night sky, be it satellites, shooting stars, falling stars after pointing at certain things with a green laser? ...

Virtually nil. You're not going to illuminate or signal anything with a laserpointer.

But, as you stand out there trying to do so, you're eyes probably adjust better to the night sky and you DO end up being able to see many more objects.

Walk outside without your laser and then spend a few minutes letting your eyes adjust, away from direct lights and such. Odds are, you'll start noticing a lot more in the night sky than you were able to when you first stepped out.

Lying on your back in a dark field with a good, unobstructed view of the sky is an amazing experience. As your eyes adjust, stars magically begin "appearing."

PS - Welcome to SDC!!

 

[MeteorWayne]

I was wondering if there are low orbit satellites that can be mistaken for something else. Distance can't be judged at night, but size is comparable no matter what. If a moving light (not blinking) was to be much lower and larger than a plane flying over there is a very obvious difference between a plane with flashing lights, with a jetstream behind it (very clear lights, and sound behind the plane) while a low flying light has no jetstream, and flies silent with a constant light.
Would there be a reason why I would see more than 3-7 satellites pass over the same area in one night?

This time of year there are typically dozens of satellites overhead each night, for example from sunset to sunrise tonight at my location there are 71!! brighter than magnitude +4.5. That's an average of 7.5 per hour. BTW, had a great overhead pass of the ISS/shuttle complex tonight just 5 minutes after sunset, (predicted mag -3.2, actual, closer to -4.5). And that's just the predicted ones.

In addition there will be a dozen or two not on the prediction list including flashers, others slowly varying it brightness, those no longer in their last calculated orbits, etc. Many flashers only flash once or twice, others dozens of times, and the period can be regular or irregular. Different flashes from the same sat can be of different brightness and length and "shape" (i.e rise and fall time of the flash). All satellites can fade out as they enter the earth's shadow, or suddenly appear if they leave it. The satellites also include Iridium flares, which can be far brighter than Venus, or as dim as any star and last just 5-15 seconds covering a small part of the sky. I have also seen flares from geostationary satellites that last 10-15 minutes and the movement is so slow they need to be close to a reference star to detect the very slow motion (a quarter degree per minute).

Not all jets have contrails BTW, that depends on atmospheric conditions at flight level. Sometimes if it's dry at 20-35,000 feet there are none. On other nights they can last across the whole sky or become permanent clouds.

And trust me, lightning bugs can be a problem when meteor observing. Once the LB season starts (as it has here) I have to make special effort to not include them in my meteor counts. To do so, I note the color, brightness, and flash pattern of treetop level bugs early in my observing session each night. That way I can be sure to keep looking near the location where I see one of the right brightness and color to see a repeat flash and confirm it as a bug.

Back to satellites, lower satellites move at a faster angular velocity than higher ones. Once I'm in form, I can usually estimate the height of the orbit within 20% from the speed, but the weather hasn't been too cooperative this season, so I'm not doing to well yet this year. I record any satellites I see that are in my observing field of view, and record their brightness and estimated orbital height during my meteor sessions. There is of course a lower limit to how low (hence how fast) a satellite can be...once it gets too low it reenters the atmosphere pretty quickly. The fastest (hence lowest) one I ever saw was about 2 weeks before reentry. It was haulin the mail! Higher satellites can last over 15 minutes from horizon to horizon.

All this is based on thousands of hours of time recording meteor data.

Meteor Wayne

 

[Xaelzc]

I understand. Thanks for the info.

 

[neilsox]

Hi Xaelzc: The others gave good answers. Laser pointers have a range of perhaps 100 meters = yards, so anything they illuminate is a flying bug, bat or bird. If you have a million dollar laser you can illuminate airplanes and possibly LEO satellites. Soon, if not already leading edge lasers can likely even illuminate GEO satellites to naked eye visibility You can expect to be arrested if you do this, as there is some possibility of a powerful laser damaging an aircraft.
If you have been observing satellites for a long time, mistaken identity is unlikely, but there is a slight possibility of black ops, airplanes, ET, missiles, meteors and asteroids, under unusual conditions, such as coming approximately straight toward you. Neil

 

[a_lost_packet_]

IIRC, some hand-held lasers can be dangerous when pointing them at aircraft. So much so there are Federal Laws involved that punish people that have done that. Such an act can temporarily blind a pilot.

But, illuminating satellites, orbiting bodies and extra-planetary phenomenon isn't possible to do with those.

 

[crazyeddie]

Green laser pointers are good for showing other people where things are in the sky, or if you are observing by yourself and you have a laser serving as an object locator, as if it were a finderscope. But it's considered very bad form to use laser pointers in the presence of other people using telescopes, such as at star parties, because they can be an annoyance. And whatever you do, don't point a laser at an aircraft, or you might find yourself being hauled off to jail!

 

[Xaelzc]

oh well. worth a try. it doesn't matter neways, i point at all kinds of stuff. i would like to see what it looks like from a satellites point of view when its looking at my laser. lol.

 

[MeteorWayne]

It would be invisible against the background of light pollution across all but the darkest areas of the planet.

 

[a_lost_packet_]

Green laser pointers are good for showing other people where things are in the sky, or if you are observing by yourself and you have a laser serving as an object locator, as if it were a finderscope. ..

Wouldn't that be only possible where there is either heavy humidity, low cloud cover or airborne particulates in the viewing area?

 

[MeteorWayne]

No, they are quite effective as pointers as long as you are close to the line of sight no matter what the conditions. Standard Equipment at astronomy clubs

 

[Xaelzc]

Was there a meteor shower last night, Wednesday night into Thursday morning, may 19/20??

 

[MeteorWayne]

No shower is active except for the eta Aquarids (at a very low rate ~ 1/hr, only visible in the two hours before dawn) and the always active antihelion radiant (Currently in Scorpio near Antares) also with 1-3 an hour well after midnight.

Of course there are sporacic meteors that come come from any direction at any time.

Meteor Wayne

 

[MeteorWayne]

I was talking with a friend on the phone discussing our exceptionally clear skies, helping him find Mars, Saturn, Leo Arcturus, Spica, etc, and while we were on the phone for 5 minutes, we saw 4 satellites. SO after that I went in and made some minor effort to see the predicted sats at Heaven's-Above. For the 1 hour between 9:25 and 10:25 PM EDT, I saw 14 sats, 11 of which I was able to ID from the list:

Cosmos 2082 Rocket
Cosmos 1943 Rocket
Cosmos 1869 Rocket
Abrixas Rocket
Cosmos 1184 Rocket
Okean 1-7
Cosmos 389 Rocket
Cosmos 1689 Rocket
Envisat
Cosmos 1833 Rocket
Cosmos 1005 Rocket

Not bad for an hour!!

I missed a few faint ones that passed by the moon early, and over the whole sky as thin cirrus overtook us.


It was clear from the angular velocity which were the newer and older Cosmos Rockets.

Cosmos 389 (Launched 1970 orbit 496x552 km) was noticeably faster than the first I saw, Cosmos 2082 (835x853 km), launched 1990.

For reference the current ISS orbit is 349x353 km.

MW

 

[Xaelzc]

I figured to ask cause I seen a couple of them, all which occured well after midnight and into early morning. I seen some satellites too, but what I saw had to be meteors or something burning up in the atmosphere. Quite a site I'll say. Much thanks.