Category Archives: Science

See the International Space Station in the night sky

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.

Online information

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.

Map of the Earth from the Night Sky app showing the ISS

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.

Screenshot from the Night Sky app showing the ISS

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.

Screenshot from the Star Chart app

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.

Interesting temperature measurements using an infrared thermometer

Earlier this year I purchased one of those infrared thermometers that you just point at things and pull a trigger to measure its temperature. Initially I had plans to use it to make the perfect cup of coffee. Well, that didn’t work out very well as the thermometer had difficulties measuring the temperature of the liquid and the shiny container. Even if it had worked the coffee probably would have still been far from perfect. I soon discovered that it is more fun using the thermometer to measure the temperature of random objects. These thermometers measure heat using infrared light. They don’t have to come into contact with an object as they measure the infrared energy that naturally radiates from it.

My thermometer - $20 from ebay

The sky

Pointing directly up into the winter sky in the afternoon gave a reading -47°C (-52°F). I found this interesting as it is not measuring an object. I assume it is just reading the amount of infrared light it can detect in the atmosphere above.

Thermometer pointing into the sky

Frost covered car

The back of the car on a cold frosty morning is -9°C (16°F). No wonder it feels cold when I get into it in the morning. That louver on the rear window makes it look cooler – A bit like the Delorian don’t you think 🙂

Thermometer pointing to the rear of a car

Frost covered flower

Probably the coldest morning of the year. The official temperature nearby was -9°C. We usually experience a bit colder temperatures here. This flower is -12°C (10°F). It’s no surprise that so many plants from other parts of Australia do not grow here.

Thermometer pointing at a frost covered pansy

Wood heater

Temperatures at the top got up to 457°C (854°F). Not a place you would want to place your hand. This is a significant difference with our reverse cycle air conditioner. When it is heating it blows warm air whereas this heater is hot.

Thermometer pointing at the top of a wood heater

Cat laying in front of the heater

Our cat loves heat and has very fine black fur. Here the fur is showing 60°C (140°F). I think the fur makes a good insulator so the cat is nowhere near as hot as this reading indicates.

Thermometer pointing at a cat laying in front of the wood heater

Cat laying in the sun

Here it is lying in the sun. I find it interesting that its fur is hotter that when it was in front of the wood heater 66°C (151°F).

Thermometer pointing at cat laying in sunshine

Regular Toast

Toast is pretty hot when it pops up. Picking it up immediately after it popped up shows it to be 123°C (253°F). Why don’t we get burned? Maybe it’s because the toast is a good insulator. Perhaps it is because the toast has a porous texture that it has a large surface area that accelerates its cooling. It certainly cools quite quickly. I don’t know really.

Thermometer pointing at a slice of taost that has just popped out of a toaster

Raisin Toast

The raisin toast is even hotter 167°C (333°F). Perhaps a raisin is influencing the reading here.

Thermometer pointing at a slice of raisin toast that has just popped out of a toaster

Other things to try

Some other fun and interesting things to try if you get a chance to use one of these are:

  • Heaters
  • Light bulbs
  • Windows, doors and walls outside at night. Leaking heat will be obvious by higher temperature readings
  • The sky at different times of the day and night
  • Food in different areas of a fridge and freezer

Detecting weak electric fields with your bare hands

Detecting when an electric blankets is switched on

I have often wondered about the effect that electricity may have on our bodies. Years ago I discovered that I could tell when Mrs Piffle’s electric blanket was switched on while she was laying on it by running my finger very gently down her arm. When the blanket was switched off it felt smooth. When it was on I could feel a slight vibration which is hard to describe. It certainly felt less smooth. We did a series of tests with her turning it through the different settings – sometimes on sometimes off, and I could always tell when it was on or off. Just for the record, the electric blanket was on a foam mattress on a wooden base.

Do I have super powers? Am I particularly gentle person? Am I just awesome? Probably not. If I can detect this when some others can’t it is more likely that I benefit from baby bottom soft skin on my hands from years of office work. A few other people who have tried it, including Mrs Piffle have been able to detect the effect too, so it seems to be common, but due to the weakness of the effect maybe we just don’t usually notice it.

Electricity from a TV antenna

I had also noticed a similar, but stronger effect when I rubbed my finger along the rabbit ears antenna that was connected to our previous television but only when the TV was turned on. I’ve read that leakage can occur within TVs resulting in some power being released into the antenna socket. So, that probably explains that one.

Power from a laptop

I had forgotten about it until recently after my wife got a Macbook Pro. She was sitting on the bed one day with the laptop connected to the charger and I touched her arm and got exactly the same vibration. We tried unplugging the power connecter from the side of the laptop and the effect stopped, plugging it back in and it returned. Another series of blind tests showed that I could tell every time if it was connected or not. We did another series later and at that time the effect felt much weaker, so there must be something else at play. These laptops are in an aluminium case which is probably relevant. It’s interesting to note that the effect only happens when it is plugged into mains power. We then tried with the lid closed in sleep mode and the effect was still there, and then with it shut down, but still plugged into the power adapter and again the effect was still there.

Mrs Piffle can even notice it herself through the tips of her fingers sometimes when she is resting them on the metal case in front of the keyboard.

The power adapter for the Macbook has a fairly low output voltage of just 16.5v – not what I would have thought could be detected with your finger.

Nothing from an iPad

We also have an iPad so I did a few tests with that – after all it also has an aluminium body, but I could not detect any difference.

Is it a form of mains hum?

The mains power her is 240v 50Hz. Perhaps the higher mains voltage is relevant, perhaps not. The frequency of the vibrations seems identical in all tests so perhaps it is 50Hz from our mains electricity, but I can’t think of away to measure it with the equipment I have. It’s odd and very interesting, at  least to me.

My technique

I found I got best results when you rub an area of skin that has no hair as the roughness of the hair makes it more difficult. Inside arms and the side of the neck seems to work well (except with the rabbit ears antenna – I rubbed my fingers up along its … ears?:)). Sometimes I use a fingertip, other times I find a knuckle works better.