See a Satellite Tonight | Hacker News Reader

See a Satellite Tonight

james.darpinian.com

221 pointsrbanffy50 comments

funny to see this today - I just used it yesterday for the first time, and saw the ISS fly by above Seattle, with the naked eye. Was so cool!

coolest part was, I saw it pass by sometime around 8:00pm. Made dinner. Ate. Did the dishes. Now it's around 10pm. Checked the app again, and... the ISS was passing by again in ~5mins. Looked out the window, and... there it is!

I had this moment of total awe - over the course of my dinner and some cleanup, that little craft, with humans in it, traveled around the entire planet, and there it is again!!

hoping to see a starlink train next, weather permitting.

Here in London we’re treated to many ISS flyovers, some almost directly overhead.

We had a nice flyover yesterday, with perfectly clear skies. See below link to a long exposure star-trail photo I captured with my iPhone.

https://twitter.com/jeffwass/status/1376619838899154948?s=21

Cool pic - did you use an App for this?

NightCap

https://nightcapcamera.com/nightcap-camera/

Definitely inspires awe. Humans 250 miles up, traveling at 17,000 mph, and you can see them with your naked eye.

My favorite part is when the ISS dot slowly fades out. It's so high up that it passes out of the sun's light before it falls behind the horizon.

Usually, if you can see the ISS flyby, you'll get to see it a couple of times. I was out at a dark sky spot one night to see 3 passes. Caught one in a timelapse sequence I was shooting at the time.

My favorite part of this experience was seeing it “turn” above my head. I was finally able to truly visualize from a first person POV, the sign wave I had previous seen on Mercator orbital projections... as seen on the wall of the classic NASA control room view.

It honestly felt like I was able to visualize a whole new dimension.

I trust that you thought you saw that, but bear in mind that satellite do NOT turn at all.

The turns you see on Mercator projections are just that: projection artifacts. Circular low earth orbits (like the ISS) are great circles on the sphere. (The equator line is a great circle for example, but there an infinity of them, with various inclinations)

The turn that you think you saw in real life is just a combination of perspective, optical illusion due to landscape or objects in your field of view, and your mental model of orbits making turns (which they don’t).

I fully understand that. It is why I put the word turn in quotes.

Apparently I could have made that more clear.

This was just a first-hand experience of the illusion that we experience of living on a flat plane being shattered.

Also worth noting:

https://heavens-above.com/main.aspx

But this has a much nicer UI/UX! The street view rendering is particularly impressive.

This is definitely slicker but Heavens Above has a very nice 'live sky' view as well as an overhead view.

There is also a smartphone app, it has an option to notify you for upcoming flyovers at your location.

I use an iOS called "ISS Finder" that sends you notification right before a ISS flyover. It points you to the right corner of the sky and gives you a short bio of the astronauts on board.

i use the same app. It's great!

I wish I could select my location instead of giving it to the website via tracking

you can, just decline the permissions and it will try to estimate a location.

From there you can click "Change Address" and set whatever address you want.

On Firefox mobile nothing shows, I'll try from desktop later on thanks

You can -- block the location request and click on 'Open Street View' to enter an address

If you block the location request it then tracks you via your IP and stores it in local storage.

While typically such actions would annoy me, I would say it seems pretty reasonable in this case.

It seems like it's just doing it's just gracefully degrading from the precise location to imprecise. I do think I tracking free option would be good though.

I’ve been using this for a few months, and I’d like to say nice job! to the author.

Really the most convenient way to find a solid starlink pass, in my opinion.

Is there a way to get the predicted magnitude?

The magnitudes are actually logged to the dev tools console. But be aware that the magnitudes calculated by all tools like this are little more than educated guesses, and the real brightness can easily be different by several magnitudes in either direction.

This is neat!

This might be a dumb question, but how far out are really accurate predictions of satellite locations good for without measurement? Like, if I kept scrolling forwards in time, how long would it take before the prediction of the satellite's location was off by an arcsecond (I'm guessing days)? Or a full degree (I'm guessing many years)?

I'm not sure what the answer is, but something to keep in mind is that most are reboosted every once in a while. Once this happens, it should be completely off.

ISS elevation chart where you can clearly see when they boosted up: https://www.heavens-above.com/IssHeight.aspx

It depends on a ton of factors. In general there's more uncertainty for lower satellites, especially ones that straddle the thermopause. The error isn't necessarily constant, it depends on hard to predict events like space weather.

For something in LEO, an arcsecond of error is only a few meters. If you're plugging data into a standard orbital model like SDP4, a few meters is within the typical error margin basically as soon as the TLEs are published.

A full degree of error would take a while. For what it's worth, NORAD publishes new TLEs for things in LEO pretty regularly, sometimes multiple times a day. For higher up objects it can be more than a week before the refresh the data.

I love this website! It’s one of the things that inspired me to make a little Arduino mini mobile mission control - https://github.com/OkuboHeavyIndustries/Mini-Mobile-Mission-...

These days, even with Los Angeles light pollution nearby, I can just look up at sunset and spot multiple satellites per minute. I remember how exciting it was to see a satellite when I was a kid. Now it is pretty commonplace, and only becoming more so.

This made clear for me just how big the starlink constellation is.

I can see the ISS or some random satelite every odd day, but I can look up and see a whole trail of starlink satellites passing over basically any time...

Previous discussion: https://news.ycombinator.com/item?id=21037167

As much as I love this type of app, I can't help but feel depressed that before we know it there will be an app that does the opposite. We are allowing governments and billionaires to pollute our view of the cosmos. The night sky is such an important part of the human experience and most people never experience it in all its beauty. Allowing American business owners and world militaries to block it from above just makes my stomach turn if I am honest.

Light pollution from cities is much bigger deal than satellites though, isn't it?

There are already apps for finding out where to go to avoid it, like https://www.darkskymap.com/. As well as just websites like https://www.lightpollutionmap.info/

this reply is nothing but hyperbole and fear mongering - I've been out in a very rural dark sky location and seen a group of starlink satellites going past. they did not obscur or brighten the view of any stars. If you really want to be concerned about something, worry about light pollution in urban areas, or people polluting the atmosphere. I'm sure the folks living in the grey smog of haze in Lahore or Mexico City would be more concerned about breathing clean air, and having clean air to use a telescope if they wanted to, than occasionally seeing a satellite flying past.

I disagree that this is hyperbolic -- to be in the wilderness is to be alone and away from humanity. A starlink train is a stark expression that one can never really be alone anymore.

When I was a kid, it was a fun/rare occurrence to see the occasional satellite -- they were more common than the night's meteors, but not by more than a factor of ten or so. Today, there are oodles.

in my mind, a starlink train is a "oh, neat, look at that", same as seeing a collection of meteors, it's not like a diesel-electric locomotive suddenly appears in your wilderness...

You can only see the trains around sunset and that only a while after launch.

On the bright side (pun intended), the easier it is to put things in space, the closer we'll be to being able to - whenever we fancy - get to an altitude where those satellites are below us, so to speak :)

So I feel like this is a self-correcting problem, in a sense. We need more astronomy capability in-orbit (and beyond!), and it'd sure be nice if we as humans could chill out up there and do it ourselves, with our own eyes, unhindered by any planetary atmosphere. The proliferation of LEO satellites only serves as further motivation toward that goal.

Internet access is vastly more important than our view of the night sky.

Saw the ISS last night completely by chance from Schloss Sanssouci.

Are the starlink satellites really visible to the naked eye?

What are the "X" numbers? They are too high to be brightness magnitude. (I think :)

That is the number of satellites visible at about the same time.

It's not as good now the Iridium flares have stopped.

I could have sworn I spotted one last night above Perth, although I was under the impression all the iridium satellites were gone

Any satellite can flare and if you look at a dark sky you'll see something go over before long. But the Iridiums were special because they were so predictable and bright. I really enjoyed pointing them out to regular people who had no idea about satellites. The ISS is the only thing now, but it's not as bright as a good Iridium flare and it stays in the sky so long that it's more like a plane flying over than a flare.

Super cool, I'm going to try this tonight!

This is extraordinary.

CORS blocked :(

what is this about a cesium widget

Very nice!

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