Who knows astronomy?

edd said:
Well the ground track of something like a Molniya orbit can loop back on itself.
Click to expand...
.
That's the ground track.
Like the retrograde orbits of the planets, it's due to the viewing location.
The satellite itself doesn't manuver at all.
 
Smiledriver said:
So, I was doing a little star-gazing tonight and I noticed one body that looked like a star starting to move. I was waiting for it to "shoot," but instead it kept moving through the sky...rather quickly.

It was roughly a south to north trajectory and I watched it until I lost sight of it over the top of my apt. building. I ran to the other side of the building, but I lost it.

What was that?

I'm in Calgary and it was roughly 11:40pm...if that matters.

Thanks.
Click to expand...


Viewed from Calgary, this chart at Heavens Above shows a couple of satellites at about 11:40 last night. (You'll probably have to fix the date to May 30 and click "Update"). One was moving roughly south to north, a bit toward the northwest. Given your description, what you saw was probably the 150 foot long body of a rocket, a Chinese CZ-4B, used to launch weather satellites.
 
MG1962 said:
You have to include time and the Earth rotation. Not all satellites in polar orbit take 24 hours to go around once, in fact I think it is impossible to do. So if a satellite takes four hours for an orbit, then in theory from Calgary we would see it travelling south twice a day and north twice a day. Make sense?
Click to expand...

Yeah, of course, thanks. That was dumb of me.
 
BenBurch said:
11:40 p - No way it is a satellite.

You see satellites when they are still illuminated by the sun which can only happen within 90 minutes or so from astronomical sunset.
Click to expand...
.
The night time in Canada is quite short this time of year... :)
 
Dancing David said:
I think that the US launches a lot of polar orbiting satellites as well.
Click to expand...

In fact all of the LEOSAR-equipped satellites that the US has launched are polar orbiters; if I'm not mistaken, the point is that a polar orbit is the only orbit that can theoretically overfly every point on the Earth's surface. Planetary mapping missions tend to use polar-orbiting probes for the same reason.
 
Dancing David said:
I think that the US launches a lot of polar orbiting satellites as well.
Click to expand...
.
As mentioned, from Vandenburg AFB just north of Santa Barbara CA.
The boosters fall in the South Pacific Ocean.. nothing there to hit, except Easter Island.
From Kennedy, there's all of South America to fall onto.. not recommended. :)
.
Post #34... somewhere here I have a photo of a noon-timish polar launch from V'burg.
 
Last edited:
You must log in or register to reply here.

Back
Top Bottom