(Prelude – a word about “apparent magnitude,” i.e., how bright stars are. It’s like golf where the scoring is backwards – small or negative numbers are brighter, big or positive numbers are dimmer. The brightest stars in the sky are about M+0 (“magnitude zero”) to M-1.5. Venus right now is very bright, M-4.7. The full moon gets up to M-13. Getting dimmer, you get into positive numbers. The stars in the Big Dipper are M+1.8 to M+3.3, which will be relevant later in this article. The human eye in a dark, clear sky can see down to about M+6, but in Los Angeles on a light polluted night, you’ll be lucky to see down to M+4.)
SpaceX is in the process of launching a whole constellation of small-ish satellites called Starlink. When done, they’ll offer high-speed internet to just about any spot on Earth.
The positives and negatives of Starlink are complex. The positive of offering reasonably priced high-speed internet anywhere is obvious. The negatives are more subtle for the general public and involve the potential for catastrophic space debris events and the disruption to ground-based astronomy.
If you’ve hung out on this site for any length of time you know that I’m a bit obsessed with the sky and love to watch the ISS pass over. (There’s a “search” button over there on the right – put in “ISS” – waste the next few hours.) Since the Starlink satellites launch sixty at a time, all into the same orbit, gradually spreading out and separating over time, the effect is that of a “string of pearls,” one satellite after another following each other in the same orbit.
This is how the internet delivery system works. You launch a bunch of satellites into the same orbit and they gradually fill that orbital plane. Then you do another plane at a slightly different inclination. And another. And another. And finally you get that picture from the Starlink site like a web filling the sky, so that at any given time at any given point on the planet you have at least one, maybe two or three satellites above the horizon for you. While they’re all travelling and will disappear over your horizon in eight to ten minutes, there will be others following right behind. You’ll always have some of them up there.
So the first reaction of many folks was, “COOL!! At night, where now we see things like ISS going over every now and then, once Starlink is up we’ll have these ‘trains’ or lines of satellites following each other any time, every night!” And about two seconds later, those who want to observe the sky and take pictures said, “SHIT!! At night, where now we see things like ISS going over every now and then, once Starlink is up we’ll have these ‘trains’ or lines of satellites following each other any time, every night!”
For the record, SpaceX is aware of the issue (and the bad publicity) and is working on minimizing the disruption to astronomy and visibility of the satellites in upcoming models. It’s not clear if this latest batch had any of the new designs incorporated into their construction.
There have been a half dozen or so Starlink launches to date, the last one earlier this week. There is, of course, a site for letting you know when you can see them, findstarlink.com. And you can use Heavens-Above.com if you’re already using that to track ISS sightings like I’ve been bitching at you to do for seven years. (In either program, obviously, put in your location, not mine. Unless you live near me.)
Tonight, I was told there was a GREAT pass of some of the Starlink 6 satellites. Great! I went out to see what the hubbub was about.
Earlier today there was supposed to be a GREAT pass of these same satellites over Florida, and a number of the launch photographers and NASA Social types I follow on Twitter were going to be looking. They universally reported a complete bust, saw nothing. So maybe those design changes are working?
I went out into the front and saw nothing at first. But it was a little hazy, the moon is bright, there are two street lights out there (you’ve seen them in my ISS photos), and the rabbits running around the front yard had triggered the motion activation on the security light over the garage. I saw nothing. A bust? Maybe those design changes are working?
I went out into the back yard where I’ve got trees and the house blocking big chunks of the sky, but also a lot more dark. And a chair to sit down it. I spent about ten minutes sweeping the sky with binoculars, figuring the Starlink satellites might be really dim. With the binoculars I’m looking at stars down to about M+5 or M+6, even with the haze and moonlight and light pollution. That’s dim, less than you can see with the naked eye even in a clear, dark sky. But I’m also looking at a very small spot of sky, so I would have to be lucky to spot a satellite.
Until something BRIGHT flashed through the field of view. I figured at first it was an airplane, a trans-Pacific flight out of LAX. I put down the binoculars and looked up toward the moon.
The first one I saw was right by the quarter moon, which is bright. Even near the moon, it was easily visible. Comparing it other stars (particularly the stars in the Big Dipper), it was probably about M+1 to M+1.5. All of them I saw were definitely brighter than all of the stars in the Big Dipper, which range from M+1.8 to M+3.3 (see the prelude above).
Then I saw the second one coming up behind it. And I had the sense to look back to the northeast where they were headed. And I saw one, two, three, possibly a fourth “ahead” of the first one I had seen. They were fading as they got down into the heavier haze near the horizon.
And. They. Kept. Coming.
The were about 25° to 30° degrees apart. I base that estimate on the size of the Big Dipper – from the tip of the “handle” to the far side of the “dipper” (Alkaid to Dubhe, if you want to use the stars’ real names) is about 25.3° and the separation between Starlink satellites was about the same order of magnitude.
All told I saw fifteen or sixteen satellites. I don’t know if this was a smaller subset that’s broken off into a different orbit from the rest of the sixty launched earlier this week or if I just missed the first forty-plus when I was using the binoculars.
The next to last one in the train was odd, sort of in between the two last bright satellites, dimmer, and while going in the same direction, it was a couple of degrees off to the east of the track that the rest were on.
Really mixed feelings about all of this. On the one hand, seeing dozens of satellites in the same orbit, following each other like that for what had to have been ten minutes or so… The five-year old deep down inside of me was just thrilled shitless to see that. I’m not gonna kid you about it.
But at the same time, as someone who has sat up all night with a set of cameras and a telescope, taking exposures from five minutes to sixty minutes, with mosquitoes or hip-deep snow and everything in between, I can see where this is going to really mess with both the amateurs and the pros doing astronomy. And folks who are trying to hunt for comets and asteroids are going to have fits.
That last bit probably worries me the most. Comets and asteroids are a one in a bunch of millions danger to the planet, but if you lose the odds you end up following the dinosaurs into oblivion. I would sort of like the folks hunting for those, many of them amateurs, to have the best conditions possible. They have enough problems with clouds, weather, light pollution, and airplanes. I don’t want to handicap them with a few thousand moving targets passing through every couple of minutes.
I mean, 2020 – right? With our luck there will be that rock with our name on it out there just passing Pluto and we could spot it and have twenty years to figure out a way to deflect it and save ourselves, but we’ll miss it because someone in East Podunk needs to be streaming high speed, high definition porn while also playing Animal Crossing…
On the other hand, if those next twenty years are like the last three, I might be on Team Asteroid.
In the meantime, now that I know what to look for, the next question is obvious.
How do I take pictures of it?