When I was young I loved watching satellites go over at night. Seeing one was quite a hit and miss affair as there was no way to know when one would be coming. Usually they were only spotted on the trek back and forth from the outside toilet. All that has changed as there is now far more to see, good sites on the internet to provide details of when and where they will be visible at your location and there is also absolutely stunning apps for phones and tablets to help.
When I discovered how easy itcould be to see the ISS (International Space Station) I knew I had to give it a try.
The ISS is larger than I initially thought. According to Wikipedia it weighs a hefty 450 000kg and measures 72m wide, 108m long and 20m high. It orbits the earth every 92 minutes travelling over 27 000 km/h at a height of around 400 km.
So what do you actually see? Well, unfortunately you won’t see an astronaut waving at the window. What you will see is the sun reflecting off it causing a flare. At its best it looks like a very bright star in fact it can be over twice as bright as Sirius the brightest star. It moves quite fast and usually disappears within a couple of minutes.
If you want to give it a try, a site that I have found useful is Heavens Above. It not only tracks the ISS, but it also tracks other satellites that produce visible flares, planets and comets.
Start by selecting your location from a map, from a database of locations or enter your coordinates manually. Next look in the Satellites section and click on the ISS link to get the next 10 day forecasts. From there you can look up the next 10 days and so on. The table will show when the next passes and where in the sky it will come up and go down. The brightness is measured in mag and the smaller number the brighter, so -2 is much brighter than 2. While you’re at the site you may want to check out the Iridium flares for the next 24 hours. The Iridium communication satellites often cause bright flares, sometimes much brighter than the ISS, that’s what I’m going to be looking for next.
You don’t need a mobile device with an app, but it can help by showing you in real time where the ISS is. There are some great apps for both phones and tablets. The apps at the bottom of the post are just those that I have tried. All of them use the built-in 3D compass in your device to detect where it is pointing. Simply hold your device up towards the sky and you’ll see what’s up there on the screen. As you move your device around it will constantly update what you are pointing at with what is there. If you have not seen one of these apps in action your may be forgiven for doubting how well this could work, but I assure you it’s good and these apps are really really cool. I use the Night Sky for iOS to track the ISS.
Looking at the sky
Armed with the time of the next visible pass I wait until about 15 minutes before it is due to be visible. Then I open the Night Sky and follow it there. Here it is coming over Indonesia.
When it gets closer I switch to the sky view. In this shot I am aiming my iPad NE towards the horizon. The ISS is just below the horizon and heading up.
Five minutes after this we saw the ISS above the horizon. It got brighter the higher it went before finally disappearing into the Earth’s shadow.
Want to see a picture?
I intended to include a photo of the ISS pass. I spent a lot of time learning how to set my camera for the best shot. I did some test shots of stars beforehand. The small screen on my camera does not show the stars as they are not bright enough so I had to guess where the camera was pointing. The test photos came out alright. I set it up on the tripod and on the night I headed out into the darkness without using any light to protect my night vision. I did a series of shots, but, and I’m embarrassed to say this… I left the lens cap on. I’ll have another go and post the results up in another post.
More about apps
Below is a list of apps I have used and found useful for astronomy, but they don’t all show satellites. Remember, all of these use the built-in 3D compass in your device to detect where it is pointing.
Google Sky Map (Android)
This is the first star and sky map that I used and I installed it on my cheap LG Optimus One P500 phone. The app is produced by Google and it’s free. It shows stars and planets but not satellites. If you have an Android it’s a great way to see how these apps work for free.
Satellite AR (Android)
This app displays the location of satellites. It’s free which makes it worth a look. It does not seem to display the location of the ISS until it within 10 minutes of coming into view.
Star Chart (Android, iPhone & iPad)
The iOS and android app publishers have different names but the name and descriptions of the apps look the same so I don’t know if they are the same or not. I use the iOS version on my iPad. It shows stars and planets, but not satellites. It’s not free either, it cost me A$2.99, but it is currently on special at A$0.99. So why have I included it? Because on my iPad 3 it is smooth and the display is simply gorgeous. Have a look at this image.
Sample Star chart screenshot. Click to see it full size.
The Night Sky (Android, iPhone & iPad)
I got this for my iPad on sale for just A$0.99. There is an upgrade option to get more information about objects, but you will not need it to track the ISS. There are two viewing options. The first is the usual point at the sky and view and the other is a map of the world showing the satellites position in real time so you can see where on earth the ISS is currently over. This is the best app I have found for the iPad to locate the ISS. It is also available for Android and I have tried the free lite version on my Android phone, but I could not get the satellites to display of it, so perhaps it is just the paid version that has that feature. One feature this app has that I have not found on other ones is that it plays some really neat spacey music while it is running. Standing outside in the dark with the stars with the music playing it feels like I’m about to be visited by an extraterrestrial.
Is it worth it?
If you’ve got access to an area where you get a good view of the sky without too much light pollution it’s definitely worth it. All our family enjoyed it. It’s something for the bucket list for any nerd.