Long Exposure Image of ISS pass. Credit: VirtualAstro
Beginners Guide to Seeing the International Space Station (ISS)
The International Space Station (ISS) is a huge space station orbiting Earth that serves as an orbital laboratory, factory, testing ground and home; Crew members conduct experiments from biology to astronomy. Including experiments for prolonged exposure to life in space for future missions to the Moon and beyond.
The ISS is major accomplishment for NASA (US), ESA (Europe), JAXA (Japan) CSA (Canada) and all the countries involved (16 in all). The space station is just over 72 m long by 108 m wide and 20 m high. Maintained at an orbital altitude between 330 km (205 mi) and 410 km (255 mi). It travels at an average speed of 27,724 kilometres (17,227 mi) per hour. Completing 15.7 orbits per day.
How to Look for The International Space Station (ISS)
One of the best things about the ISS is that you can see it with your own eyes from Earth! Therefore, it’s very easy to watch the International Space Station pass over your own backyard!
All you need to do is understand when the ISS will be passing over your location and where to look for it in the sky. Check this by using an ISS pass predictor app/website or follow VirtualAstro on twitter for updates.
Once you have found out when the ISS will pass over your location. All you need to do a few minutes before the pass, is go outside and start looking in the right direction of the sky.
Starting from a westerly part of the sky
The International Space Station always passes over starting from a westerly part of the sky. But not always from the same point. It can be low on the horizon for some passes and very high others. Most of the apps or websites will tell you what direction in the sky the pass will start and end.
How many degrees above the horizon the starting and ending points are. Also included are the highest altitude the ISS will be. For example, if the maximum elevation is listed between 74-90 degrees above the horizon.
The ISS will pass straight overhead (Just like you learned in geometry, 90 degrees would be straight up). If you aren’t sure about where to look, a good rule of thumb is a fist outstretched at arm’s length is 10 degrees.
If the ISS will be first be seen 40 degrees above the horizon, look four fist-lengths above the horizon. Check apps and websites for where and what track the ISS will take on each individual pass.
Duration of a Pass
When the station passes over it will travel from a westerly direction, heading in an easterly direction. An average good pass can last about 5 minutes.
The ISS looks like an incredibly bright, fast-moving star and can be mistaken for an aircraft. However, the ISS has no flashing lights and it can be much brighter. It seemingly just glides across the sky.
Short passes can last a few seconds to a few minutes and you can see the international space station slowly move into the Earth’s shadow. Good bright passes will show the ISS moving across the sky from horizon to horizon.
ISS long exposure photograph over Donnington Castle UK Credit: www.Perfexion.com
The International Space Station usually takes around 90 minutes to orbit our planet. So, if you’re really lucky you can get two, or maybe even three or four passes in an evening or morning.
Not only can you see the ISS in the evening but you can also see it in the mornings. Both the ISS and Sun are in the ideal position to illuminate the spacecraft at this time. The light we see from the ISS is reflected sunlight.
You can’t watch the ISS pass over during the middle of the day. This is because in the daytime the sky is too bright (although some people with specialised equipment have seen it). You cannot see the space station in the middle of the night. It is in the Earth’s shadow and no light is being reflected from it.
Always Changing Position
The position that the ISS will be in the sky changes every night. The space station does not take the same track or orbital path for each orbit. This change provides good visible passes roughly every 6 weeks in each location on Earth.
Occasionally if a spacecraft such as a Soyuz crew capsule, ATV, or a Progress resupply vehicle have been sent to the ISS. You will see objects preceding or trailing the station as it moves across the sky. These can either be very close to the station or the distance between the objects can be measured in minutes. To check if there are any other spacecraft with the international space station during a pass, use the pass prediction app, or the Heaven’s Above Site.
Seeing the ISS is an incredible sight! Just remember there are people on board that fast moving point of light!
Good luck!
ISS long exposure photograph Credit: Mark Humpage
I believe I saw the ISS with my mom one night from her balcony, it was very high up and it looked like two stars on top of each other!
Can this be seen in Cyprus ? Would love my nephew to see Santa on his way !
Ask @virtualastro on twitter and they can check for you closer to the time. It may be visible some day shortly after the UK
I live in Sligo, Republic of Ireland. How am I find out the best time to see ISS? Is it visible in The Republic of Ireland?
It is visible almost the same time as it is visible in the UK, just a few seconds earlier. Follow Virtualastro on twitter for alerts and check the times here regularly so you don’t miss a pass 🙂
Is there anything of the ISS visible with binoculars?
Its fast but doable seeing it in binoculars
How will I be able to see it from Dublin Ireland? And around what time?
Same time as the UK, It’s Geographically the same place in terms of seeing the ISS
Hi, we’ve been looking for the past 4 nights and haven’t seen it yet. What are we doing wrong? East London/Essex
Follow the guide on the timetable page and you should be able to find it 🙂
We live in Larne. Belfast. Northern Ireland.
Can you give me a rough time as to when it will be passing over us for our 8 yr old to see.
Thank you so much
Times for Norther Ireland will be the same as the rest of the UK 🙂
Brilliant white light. Looked like a star that did not twinkle. Wish my father was alive to see this heavenly man-made “balloon”! Next best thing to seeing the Concorde and the Space shuttle.
Just seen it, very bright and could not be missed. Amazing to think of the speed its travelling, and that people are in it. Hope its a clear night again tomorrow.
saw this spectacular view last night and tonight,my son saw it too and it has him hooked into looking for more information . awesome,shall be looking up at the sky ay night more than ever now.
what can i expect to see tonight 27/1/13
Nothing until mid February
I can thoroughly reccommend the StarWalk app for Ipad/iphone etc
Hi Guys thanks I have read a lot about astronomy in the last 20 years and believe outward bound is the most natural evolution path.
But to read on the internet about CERN and super novas is fascinating and sometime cold.
To see the international space station glide overhead and know living souls in it are doing experiments.
This is exciting and that’s why we need human space travel.
If there was no human just computers and robot control then why bother.
In the next 10 years with Helium 3 rush to the moon and solar sail and magnetic sails, scram jet, rail guns, etc. and new economic power such as China competing with the currently established one?
I’m housebound because of disability, but I still like to track the ISS in real time using a free prog that I DL’d from http://www.download.com called Stellarium. Maybe not as thrilling as watching the actual, but still lets me play “outside”.
God bless you Darren.