The image was obtained using a Nikon D-80 digital camera fitted with a Nikon 18-70mm zoom lens set to the shortest focal length and aperture f6.3. The exposure was 68 seconds long. The ISS moves from right to left during the exposure.

Using a a piece of software called 'Makali'i Image Processor', it was possible to measure the relative brightness of the trail across the image. The result is below.

The technique used was to allow the software to sample the trail and produce a dataset that consisted of a brightness value for each pixel group along the length. Although not particularly obvious from the image, there is a slight dimming due to an encounter with light cloud to the left of the flare. The cloud shows as a faint red glow as it reflects local urban lighting. The sky also brightens towards the bottom of the image frame where the trail starts. Both of these affected the raw readings taken from the trail.

These effects were taken out of the equation by creating what was effectively a 'dark slide' of a thin slice of sky immediately adjacent to the trail and deducting the results from the trail measurement.

The result is a plot that describes the flare very well. There are some features to note on the plot. The slightly rhythmic section at the left of the trace and the two spikes prior to the flare maximum (ie to the right of the peak) are stars within, or very near to, the trail. The two on the right are very obvious in the image.

The flare itself is not a smooth event, with a step occurring on the rising slope of the flare curve.

The technique is good for relative measurement but does not provide absolute values of brightness.