Determining the target size in pixels
To understand the size of a target on the Telesto detector, compute the size of the object in the sky first. Then compare it with the resolution of the telescope and see if it is visible.
Example - Galaxy M51
Galaxy diameter = 60'000 light years
Galaxy distance = 31'000'000 light years
Telescope resolution (1x1 binning) = 0.34 arcseconds/pixel
Size on the sky = diameter/distance = 0.0019 radians = 392 arcseconds.
Number of covered pixels = size/resolution = 1153 pixels.
So you can expect your galaxy to cover about 1153x1153 pixels on you detector.
Remember, the detector measures 4096x4096 pixels!
