Shooting the International Space Station
The ISS is the largest manmade object that has ever been in space, and you can see it from your back garden. Currently it has a mass of nearly 200 tonnes and an area of nearly 100 m2. It completes an orbit of the Earth every 90 mins at a speed of 18,000mph and an altitude of 400km. Final size will be the equivalent of an international soccer pitch – 108m x 73m and have a mass of 450 tonnes.
Find out when it is going over your house at:
Qfocus is a good program to capture the video images:
Process your images with Registax:
We have the equipment to enable you to take a picture of the ISS: 200mm Newtonian reflector on a Dobsonian base, a Philips Toucam webcam with 1 1/4" eyepiece adapter. Don't forget the accessory case with the finder and eyepieces!
You will need to borrow a laptop from family or friend. Ask the owner to be the computer operator as you will be handling the telescope end of operations.
You will first need to find out when the ISS is going over your house. The Heavens-above.com site can give you details of fly overs in the next two weeks. Look out for times when the dec angle is large as this will mean you can shoot through less distorting atmosphere.
Set the kit up carefully. Make sure the laptop is on a firm table and that you will not walk in to the USB cable when the webcam is attached to the telescope. The ISS is a bright object so that you can have a reasonably well lit work area.
It is vital that the finderscope is accurately aligned as you are going to use it to track the ISS. Use a bright star or planet to get the finderscope crosshairs smack in the centre of the telescope field of view.
Now remove the eyepiece and attach the webcam to the focuser using the 1 1/4" adapter. Focus the telescope until the image of the star is as small as possible on the laptop screen. You will need to use the slowest shutter speed - 1/25 sec. Set the image size to 352 x 244. This allows 5 frames per second to come over the USB to the computer without compression.
Point the telescope in the direction you are expecting to see the ISS to rise and practice swinging the tube in the predicted arc whilst looking through the finder. Ask the computer operator to keep an eye on the time and count down the expected appearance.
As the ISS appears the computer operator needs to switch the video capture on and you need to get the object in the viewfinder and on the cross hairs. You will have a maximum of two minutes and probably much less but you only need to get ISS on the webcam chip for a second or two to have several images.
If all goes well you will be able to see an indication of structure in your image of the ISS. You may be able to stack the pictures in Registax to improve the resolution.