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Starlink Satellite train

Old 24th Mar 2021, 22:19
  #41 (permalink)  
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Originally Posted by netstruggler View Post
The BBC are predicting clear skies for me at 4:20 am and my Bedroom window faces WSW so it couldn't be much easier.... I just need to set an alarm and then remember what it was for in time to go to the window.
Well, I can't be all that far from you and on the strength of the met office prediction, I've set my alarm... I'll have to wander outside though.
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Old 24th Mar 2021, 23:42
  #42 (permalink)  
 
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Originally Posted by NineEighteen View Post
Shhh! It’ll upset the astronomers among us.

😬
Agreed..the first train was interesting, now....

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Old 25th Mar 2021, 02:43
  #43 (permalink)  
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Geostationary orbits are a long way away. I'm surprised there'd be any competition for those, but of course, they're limited to a fairly narrow latitude band.

If Jeff Bezos gets his way, the darn height will be about England stood on its south coast. Mind you, Starlink looks like they'd give flight crew a start.
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Old 25th Mar 2021, 09:03
  #44 (permalink)  
 
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Originally Posted by treadigraph View Post
Well, I can't be all that far from you and on the strength of the met office prediction, I've set my alarm... I'll have to wander outside though.
Well I woke up. The sky was clear and I could see plenty of stars (for the city) - but I didn't see any train.

Maybe I wasn't looking at the right angle but I assumed if it was visible it would be impossible to miss?

I did go outside to see if they were overhead, but no luck there. If they were low then there's a row of street lights that probably did for me.

Did you see it?
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Old 25th Mar 2021, 11:02
  #45 (permalink)  
 
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Originally Posted by Loose rivets View Post
Geostationary orbits are a long way away. I'm surprised there'd be any competition for those, but of course, they're limited to a fairly narrow latitude band.

If Jeff Bezos gets his way, the darn height will be about England stood on its south coast. Mind you, Starlink looks like they'd give flight crew a start.
The useful positions in the geostationary belt are just about full, and are much prized.

The daft thing about LEOs is that anyone with enough cash can chuck as many up into orbit as they choose and there seems to be no end to the process. The only control is on the frequencies they use. Astronomers just have to accept any problems they create for now or in the future.
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Old 25th Mar 2021, 12:33
  #46 (permalink)  
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No, sky was clear overhead but there was a certain milkiness in the sky which obscured all but the brightest stars as you looked more towards the horizon. I reckon they should have been about 30 or 40 degrees from directly overhead. I did see one satellite that was closer overhead, apparently from an earlier Starlink launch. Think I also saw a meteor! Blackbirds and robins were all trilling away merrily!
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Old 25th Mar 2021, 12:52
  #47 (permalink)  
 
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Originally Posted by Loose rivets View Post
Geostationary orbits are a long way away. I'm surprised there'd be any competition for those, but of course, they're limited to a fairly narrow latitude band.
As Sallyann says the geostationary slots are a limited resource and quite valuable.

https://space.stackexchange.com/ques...tationary-belt
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Old 25th Mar 2021, 13:33
  #48 (permalink)  
 
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Thank you Wiggy, I just followed that link and spent a good half an hour realising how dumb I am. I also spent half of that trying to work out what "Tesseral" meant. I still cannot explain it, but if the pubs were open I would drop the word in conversation with certain of my drinking group to send them off on a wild goose chase of the term
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Old 25th Mar 2021, 13:37
  #49 (permalink)  
 
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Gordy's link is awesome but I suspect there is a flaw. If the satellites are in Earth's shadow then I doubt they can be seen.

A few hours after deep sunset or a few hours before twilight would be the ideal viewing time methinks.

Patchy cloud around my parts but the link suggested one of the trains would pass at 8:41pm - I saw a few moving things up there but not sure if I saw the train, have to wait for a clearer night.
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Old 25th Mar 2021, 17:55
  #50 (permalink)  
 
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Starlink

Sorry to offend all you astronomers but... my summer cabin is at 50N-122W in lovely British Columbia. No roads, no cell service, no utilities (except what I generate with solar.) My current connection with the world is Xplornet satellite. On a good day I get 2 to 3 Mbs download. This costs $129 month. I am anxiously awaiting my Starlink "dishy". Deposit is already paid. Beta testers are showing downloads of up to 300 Mbs. Same price as Xplornet. It's an easy decision for me.
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Old 25th Mar 2021, 19:21
  #51 (permalink)  
 
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Originally Posted by cattletruck View Post
If the satellites are in Earth's shadow then I doubt they can be seen.
Correct, and since the starlink satellites are in Low Earth orbit the period of time you, the observer, have dark skies, and the satellites above you are being illuminated by direct sunlight can quite short.

Over the months I've found the trains aren't always that easy spot, even from a dark sky site, so I wouldn't be at all surprised if one got missed from a light polluted area.

BTW I've used the Heavens Above site for years, I know the the interface isn't perhaps that fancy but it works.




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Old 25th Mar 2021, 19:46
  #52 (permalink)  

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App checked. Due overhead at 04:55 onwards - how exciting; at last something to look forward to, break the terminal Covid lockdown boredom!
Alarm set 04:45.
Slept fitfully till 04:40, pre-empted alarm (senior gentlemen's reasons, dealt with that).
Put on slippers - well one slipper actually - my son's dog that we seem to have adopted recently is a chronic slipper thief.
Crept carefully through the house, using a small torch to preserve night vision and so's not to wake the other half.
Re-checked the App - They're coming, They're coming, should be right overhead in a couple of minutes!!
Carefully unlocked and slid back the patio door.
Hopped out onto the cold patio slabs, in pyjamas and the one slipper, shivering slightly.
Looked skywards....for ten minutes. Didn't see a damned thing.
Went back to bed, feeling very cold and rather silly.
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Old 25th Mar 2021, 19:53
  #53 (permalink)  
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Originally Posted by ShyTorque View Post
A
Slept fitfully till 04:40, pre-empted alarm (senior gentlemen's reasons, dealt with that).
Yes, me too...
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Old 26th Mar 2021, 11:52
  #54 (permalink)  
 
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Originally Posted by wiggy View Post
As Sallyann says the geostationary slots are a limited resource and quite valuable.

https://space.stackexchange.com/ques...tationary-belt
Thanks, for that, wiggy. As you say, the geostationary belt is quite full. As has been mentioned, there is potential for interference if the geo satellites get close, but there is also a risk of collision, especially when you consider that some satellites stop operating and there's nothing you can do to move them, so you have to move others out of the way. Then there's whatever some company or country used to get their satellite into that orbit and might have been discarded.

One other thing to consider is that I suspect most people think that a satellite in geostationary orbit is stationary relative to someone on Earth. They aren't. Although they generally stay within a belt and close to where they should be, they actually do all sorts of loops and strange shapes while staying close to their supposed position from an Earth-observer's perspective. Considering all that, ground-based telescopes are used to detect if any operational satellites are in danger of collision and if they are, the ground-based observations are used to let the various companies know when and where to move their satellites.

A lot of work goes on behind the scenes to keep the world in touch!
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Old 26th Mar 2021, 12:36
  #55 (permalink)  

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Parking space problems in space. Who would have thought it?
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Old 26th Mar 2021, 13:39
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Originally Posted by ShyTorque View Post
Parking space problems in space. Who would have thought it?
Think of it more like a busy marina and a couple of boats getting loose. You know where everything is, all the boats are in a confined space, but you don't know what damage will be done until those boats are brought under control. I apologize for not knowing the maritime phrasing for this. But everyone else is worried that a rogue boat might hit their boat, and given enough warning they move their boats away from danger just to be safe!

Unfortunately, it's not like when we were kids using paddle boats and the scary guy with the loud hailer shouted "Come in number 3, your time is up!".
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Old 26th Mar 2021, 15:37
  #57 (permalink)  
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Huh, that sounds like my first job. 10/6 a week.

Now you mention it, of course, the Inmarsat relevent to the M370 made a huge 8 with the top loop smaller than the bottom. Yes, a lot of space taken up.
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Old 26th Mar 2021, 15:56
  #58 (permalink)  
 
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Originally Posted by Hokulea View Post
Thanks, for that, wiggy.




One other thing to consider is that I suspect most people think that a satellite in geostationary orbit is stationary relative to someone on Earth. They aren't. Although they generally stay within a belt and close to where they should be, they actually do all sorts of loops and strange shapes while staying close to their supposed position from an Earth-observer's perspective.
You'l know a lot or all of this, for those that don't..

https://celestrak.com/columns/v04n07/
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Old 27th Mar 2021, 08:18
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Thanks, wiggy! I did know this stuff since I've been involved in various projects since 2014 in observing orbital debris in high-earth orbit (i.e., geosynchronous orbit) but hadn't seen that web page before. It's very good and summarises things well. It's something I will definitely use in the future if and when I need to explain orbital debris and its potential effects. I think many people concentrate on orbital debris being a problem in low-earth orbit or something that's a threat to astronauts and space stations - which of course it is - but don't consider the threat to our whole satellite communication network.
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Old 27th Mar 2021, 08:56
  #60 (permalink)  
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Spacex has now launched 1300 satellites out if a planned 1500, at their current launch rate that should be finished in 6-8 weeks (which is mind blowing in itself).

At which point they will reportedly switch to regular polar launches out of Vandenberg - which should provide good views in the higher latitudes.

The first 10 were launched on 24th January Transporter-1 mission which launched 133 satellites for various customers. The 10 were launched to an altitude of approximately 500-kilometers above Earth to operate in Sun-Synchronous Orbit (SSO).

The polar satellites transfer data between them using [email protected] so no ground stations are needed in the polar regions.


https://www.theverge.com/2021/3/26/2...rctic-military

OneWeb and SpaceX are racing to beam internet to the Arctic

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