Have you watched the ISS flyover you before and waved to the astronauts living up there?

Would you like to be able to do it more frequently?

Have you never seen it before and want to?

You don’t have to be an astronomer or rocket scientist to watch it flyover and wave to the astronauts living aboard it! It’s as easy as checking Twitter, and finding out when to go outside and then knowing where to look!

I usually always photograph these ISS passes by myself, but I would really like to start sharing the awesomeness that is watching it flyover with more people, not only on campus here at Purdue but across the USA, so I am going to start posting the better upcoming International Space Station passes over on myTwitter, Facebook, and Instagram in hopes that I can share the amazing fun that is watching the ISS flyby in mine/your morning or night sky!

I think it would be really fun for many reasons but here are a few:

1. To generate a following of people that all enjoy watching the ISS fly over.

2. To hopefully inspire some young kids in the process to get involved with/become interested in STEM/space.

3. To give a way for the crew to connect with folks on the ground here knowing there are a bunch of Earthlings waving each time they fly visibly over the US!

4. To connect with students on my campus at Purdue who are already interested in science/space/etc and show them what it’s like to see it and how frequently it actually flies over us! (some people don’t realize it is almost nightly sometimes)

If you’ve never seen the ISS flyover before, you’re probably wondering now, how you might do that. Here’s some terminology to understand first so you can watch your first ISS flyby:

Time of Pass – when the  opportunity to view the ISS will begin in your local time zone. All sightings will occur within a few hours before sunrise or after sunset. This is the optimum viewing period as the sun reflects off the space station and contrasts against the darker sky.

Visible – the time period from and to when the space station is visible before disappearing from your view.

Max Height – measured in degrees (also known as elevation). It represents the height of the space station from the horizon in the night sky. If you hold your hand flat out in front of you, parallel to the ground, the horizon is at zero (0) degrees, and holding your hand perpendicular to the ground directly overhead is ninety (90) degrees. If you hold your fist at arm’s length and place your fist resting on the horizon, the top will be about 10 degrees. If you stack your fists together, you can figure out about where the ISS will be (max height) in your sky.

Appears – the location in the sky where the station will be visible first. This value, like maximum height, also is measured in degrees from the horizon. The letters represent compass directions — N is north, WNW is west northwest, and so on. If you don’t know which way is which, many people have smartphones nowadays, try finding a compass app to help you find out which way is which. The sun rises in the east, and sets in the west.

Disappears – represents where in the sky the International Space Station will not be visible anymore. Also represented by values such as WNW or N. Use a compass app to help you.

The map below corresponds to images like this that I will be sharing on my social media:

the upper left image (sky map) shows what track the ISS will follow as it flies across my sky, here in West Lafayette at Purdue University. If you live close to me, relatively (Indiana, Illinois, Iowa, Kentucky, etc) this is what your pass will look like.

The upper right map shows a viewing circle, where that circle extends outward from either side of the black line shown, where the ISS will be visible from.

and finally, the lower image shows the track the ISS follows across the United States on a larger scale for you to judge whether or not you might be able to see this pass. The blue portion of the line is the invisible portion, whereas the green portion is the visible portion.

Basically if you are between the two red lines shown, you should be able to see the pass very well in your sky! And this goes for every pass! Every image like the above ones I share, will have this information to help you.

The times shown will always be in Eastern Time (New York, Florida, etc), so if you live in places like Texas or Illinois, you are going to subtract one (1) hour from those times, and this pass will be viewed at 6:30 PM local time on January 20th, 2016.  If you are near places like Colorado, you subtract 2 hours (5:30 PM), because you are on Mountain Time. California, 3 hours (etc).

The green and red arrows in the image show where the pass will start(green) and end(red). The ISS will always fly from the W towards the East, whether that be NW-to-SE or SW-to-NE, or even East-to-West in some places, never in the opposite manner.

“Now I am outside, I saw your picture/tweet/post on Instagram/Facebook/Twitter, It is about 5 minutes until the pass, and I am waiting for the ISS, what am I looking for in the sky?”

You are going to look for what appears to be a moving star, but is actually the ISS – with six astronauts living aboard it. If what you see is blinking, that is an airplane, the ISS will be a solid white star-like dot. It will move quickly; seeming faster and faster as it approaches you, and then appear to slow down as it moves away from you.

“I see it!! I see the ISS! What do I do now?”

Well first, you can marvel in the fact that you are looking at a spaceship the size of an american football field cruise by you and is being illuminated by the Sun 3 million miles away with usually 6, sometimes 3 people living aboard it.

You can even track when the next passes are for you. It is pretty easy. You do this:

1. head to heavens-above.com

2. Log in/make an account (they never email you)

3. Add your location (City, State)

4. Click “Update” at the bottom of the page

5. Go Back to the Homepage and click “ISS” and there you will find a list of all the upcoming passes in your local time, and the start times, max height, and disappear time of each. The times will be listed in a 24 hour clock format: so, 00:14:28 is 12:14:28 AM local time for you; 6:28:15 is 6:28:15 AM local time for you and times like 18:47:54 is 6:47:54 PM local time for you. (12 + 6 = 18, just a different format clock)

6. The lower the number (-1.0 or lower usually) are the best passes.

Example of a list you might see:

Have a smartphone? Snap a photo as it flies by and tag me or send me it!

Twitter: @TrevorMahlmann

Instagram and Snapchat: @TMahlmann

I will be alerting of passes like this on my social media, so make sure you are following there, and I will be sharing my images of the passes I take like the one at the very top and hope you will join me in watching the ISS flyover!

Did you watch the ISS after seeing one of my notifications? Tweet at me and @StationCDRKelly, @Astro_timpeake and @Astro_Tim and tell me you waved!

The astronauts sometimes tweet back or favorite/like the tweets/post, so you never know! Thanks for reading! I will be writing a new blog post every Sunday, so check back next Sunday for more!