Why is the image of Cydonia only 1024 pixels wide?
This question has been asked a great deal over the past few days. The field-of-view of the MOC is 0.44°, and at the range of the Cydonia image, this translated to about 3.1 km (1.9 miles). The viewing angle was about 45°, so the projected width of the field was about 4.4 km (3 mi). The narrow angle detector is 2048 pixels across, so the intrinsic resolution was about 2.1 m/pixel. The maximum image size (in bytes) is 9.8 MBytes, or 2048 X 4800 pixels. At 2.1 m/pixel, this permitted a down-track field of view of 11 km. Considering the uncertainties in pointing of the spacecraft, this 11 km downtrack dimension was considered insufficient to insure a reasonable chance of hitting the target. There are two ways of extending the downtrack dimension. First, we can use “lossless” compression to extend the distance by a factor of about 1.8. We do this with most of the MOC images. However, losses within the communication system occasionally create black bands (accounting for the loss of about 7-1
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- Why is the image of Cydonia only 1024 pixels wide?
