Asteroids are impossible to spot in single images so we need to use software to find them. To identify an asteroid, we have to catch it moving. This article will show you how to you a free piece of software called astrometrica to do this.
There are two ways to do this.
(1) You can expose the patch of sky for a sufficient amount of time so that the asteroid streaks across the image and leaves a large line.
(2) Take several images of the same patch of sky some time apart. This can be done with as few as two images. When you have your images, you can make a mini video of them. Doing this allows you to see the asteroid move against the background sky, and provides data which you can measure accurately.
In Astrometrica we can do a similar thing by "blinking" images. This is the process of showing you your images one after the other in quick succession which appear to play like a video.
To do this, open Astrometrica and go to File > Load Images.
Browse to the location of your computer with the asteroid FITS files on and open up to 5 of them.
Each time an image loads, you see a little box containing the Date and Time the image was taken. This is read from the FITS Header of the files so you can assume this is correct - click OK for each image.
To blink the images, go to Tools > Blink Images. A new window will appear with the video sequence - in the heading of the window you will see it is toggling though the image numbers.
Now take a look at your video. You can see that most of the white blobs (stars) stay still and only perhaps fluctuate in size and brightness. Watch out of the white blob that moves..... That is your asteroid.
An example of an asteroid moving across the image is shown below - it was so fast that it moved by the time the filter wheel on FTN had changed from red-green-blue!
