Reach Out, Touch Space

There are really good odds that there are a couple of opportunities in the next week for you, yes, YOU(!), to personally see spacecraft and/or the opening of a new spaceflight museum!

For pretty much everyone in the Northern Hemisphere, this is an excellent time of year to spot the ISS as it passes overhead. The further north you are, the better the opportunities for multiple sightings in one night.

We’re fairly far south here in LA (34°) so we’ll have the opportunity to see one or two passes some day, generally one after sundown and one before sunrise. For example, Flyby says we have an extremely bright pass on Saturday night at 21:20 (we’ll be at the Hollywood Bowl) and again on 05:26 on Sunday morning. Sunday night there’s a pass at 22:03, then Monday morning a really bright one at 04:33. Monday night at 21:09 will be very bright, Tuesday morning at 3:40 will be so-so. Tuesday night at 20:16 will be very bright… You get the idea.

If you’re further north, you might have as many as four passes a night because of the way the ISS’s orbit is aligned with the Earth’s terminator right now. It happens twice a year (well, twice a year for the Northern Hemisphere, then twice a year for the Southern Hemisphere) during periods referred to as “high beta-angle” periods. The “beta-angle” is the angle between the plane of a satellite’s orbit and the sun. If you don’t want to do the math, the tl;dr version is that  at times of low beta-angle, a satellite gets roughly 50/50 time in sunlight and night, while at high beta-angles it can be in almost continuous sunlight. (If you are interested, there’s a good article here on it.)

With ISS in constant (or near constant) sunlight for several days, if it’s going overhead any time during your night you’ll probably have a chance to see it. Since the ISS will typically be above the horizon four or more times a day for any given location on Earth, that’s a lot of sighting opportunities.

There are many ways to see when the ISS is visible at your location. Primarily I use the Flyby app, but you can also go to the NASA “Spot The Station” site or Heavens Above, both of which are excellent. Just put in your location and they’ll let you know when to go look, where to look to see ISS rising, which direction it will be heading (always generally west-ish to eash-ish), how long the pass will be (typically four to ten minutes), how high it will get in the sky, and how bright it should be.

To the naked eye, ISS will look a bit like an airplane’s bright landing lights, but you won’t see any red or green navigation lights, it won’t blink like an aircraft strobe light, and it will travel in a straight line at a pretty good clip right on across the sky. It will almost always be the brightest thing in the night sky, rivaled only by the moon, Venus, and possibly Jupiter.

How fast is “a good clip”? Well, if it goes right over your head from horizon to horizon, it takes about four and a half minutes to go from the horizon to straight overhead, then another four and a half to get to the opposite horizon. If it’s lower down in the sky, it will be visible for less time. But that should give you an idea of how fast it will be moving.

You don’t have to be in a dark sky location to see ISS. We see it all the time from the heart of Los Angeles with all of the light pollution that involves. If you’re in a dark sky location you’ll see it better, and you’ll have a good chance of seeing several other satellites while you’re waiting for ISS. But no matter where you are, if it’s clear and after dusk, you’ll be able to see it.


If you’re on the US East Coast in the mid-Atlantic region this Saturday and looking for something “spacey” to do, I suggest you go to the Grand Opening of the Spaceflight America Museum & Science Center in Prince Frederick, Maryland. That’s on the western shore of Chesapeake Bay, south of the Washington-Baltimore area.

The museum is connected to the Arthur Storer Planetarium, which was renovated in 2014. Both the museum and the planetarium are part of Calvert High School. Arthur Storer was the first astronomer in colonial America and made significant contributions to the field at the time. He was a contemporary and friend of Isaac Newton and made key observations of what would later be known as Halley’s Comet.

One of the folks behind the new Spaceflight America Museum & Science Center is Dan Bramos, a friend I met at the NASA Social in Washington a month ago. Dan and the other volunteers have put a ton of work into getting the museum off the ground and they’ve got big plans for things to come.

If you’re in the region, consider going down to Prince Frederick on Saturday, May 30th, to join in the Grand Opening. (Tell Dan I sent you!) If you can’t make it Saturday but are or will be in the area in the future, check out their hours and go visit then. Follow the museum on Twitter at @Learn2LoveSpace. No matter where you are, you can become a member of the museum to support it ($25/year and up).

Spaceflight America isn’t the Smithsonian, but it’s a terrific local site and organization that’s working in the community to promote scientific, technical, engineering, and mathematical education. I’ll be supporting them and visiting when I can. Please consider doing the same.

1 Comment

Filed under Astronomy, Space

One response to “Reach Out, Touch Space

  1. Assuming, of course, we can shake the May Grey and the June Gloom… I’ve had two opportunities to take the ‘scope out in as many months because of either the Moon or the humidity… grrrrr


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