High Beta Angle Time Again!

Look to the skies, peeps! It’s one of the two times of the year when the International Space Station is orbiting at a high beta angle!


Look to the skies, peeps! It’s one of the two times of the year when you can see the ISS almost every night and it will be amazing and bright and spectacular!


There was a spectacular pass of the ISS over Los Angeles tonight just after 20:30. It went right overhead, through the zenith, which means it was a long, long pass. I watched it for over eight minutes. It went right next to Jupiter, which is pretty stinkin’ bright itself, but the ISS was even brighter and moving along at a good clip. Not to mention that we built it and put it up there and have been living in it constantly for over fifteen years and right this second it’s got six astronauts and cosmonauts living onboard.

Not to mention.

While thinking about writing this, I sort of remembered that it had come up before. A quick search and I found this article from May 27, 2015, where I wrote almost the exact same thing I was going to write tonight. (Go read it, I’ll just hit the high points here.)

Is it a coincidence that the article I wrote last year is almost exactly a year ago? As you might expect from the tone of the question, there’s nothing coincidental about it at all. It’s a product of celestial mechanics and orbital dynamics.

I will recommend to you yet again a good article about what “high beta angle” is, but the tl;dr version is that the station’s orbit is tilted with respect to the Earth’s equator, the terminator that separates night from day is tilted with respect to the Earth’s equator, and twice a year they get close to being tilted the same amount and lining up. When that happens, the ISS is in sunlight constantly for several days. When it happens to be over you and it happens to be after dark where you are and the ISS happens to be brightly lit above you, you get a spectacular show.

My thanks to Ron Baalke who put the word out on Twitter that I first saw.

The diagram he attached is from Heavens-Above.com, which is a site you MUST be familiar with if you love seeing spacecraft passing overhead. As you can see, rising in the southwest, four minutes later it went right by Jupiter, through the zenith, through the “handle” of the Big Dipper at 21:38, then off to the northeast.

I spotted it coming up from behind the hill and houses to our southwest. I think it might have been the lowest and earliest I’ve ever seen it rising. It was extremely bright and its movement is distinctive.

When it went by Jupiter it was a sight to behold. I wish that I could have been able to know enough in advance to set up my telescope. It would have been possible to catch both Jupiter and the ISS in the same frame even through the ‘scope. You don’t get chances like that very often.

Just after it passed the zenith, at about 21:38:30, with the ISS still clearly in sight, I spotted very near to it (from my viewpoint, they were in fact separated by hundreds if not thousands of miles) a polar satellite, heading from due north to due south.

How often do you see two bright satellites passing overhead at once? It might be more common out away from the city lights. In fact, there’s getting to be so much up there that in a dark sky just after sunset, it might be something to see several times an evening. But here in the bright lights of the big city where only the brightest can be seen?

That was special.

I wasn’t the only one who was on alert. My Twitter feed lit up with videos and pictures, from both the space savvy:

and from the more mundane (but no less revered in this household):

It was amazing that you could see it so clearly, not just from the San Fernando Valley with all of its street lights and shopping malls, but even from LA Live (where Bailey was) which as you can see is lit up like a Christmas tree on steroids (I hope this embeds correctly, it’s the first time I’ve tried this):


Even astronauts were impressed:

So celebrate high beta angle season and go look for the ISS tonight!

1 Comment

Filed under Astronomy, Space

One response to “High Beta Angle Time Again!

  1. Watching the ISS’s view that you posted the other day, it seems to be favouring your track at present. It seems to be a while till it gets back over Europe. Maybe I should check when it’\ll be back in view for us!


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