Several other artifacts that are common in saturated stellar images are also obvious in Figure 4.3. The spider diffraction spikes caused by both the OTA spiders and internal WFPC2 spiders are at 45° to the CCD columns in all cameras.
The halo around the stellar image is well above the diffraction limit in intensity. Also there are ghost images which result from internal reflections in the filters and in the field-flatteners. These topics are discussed fully in the next Chapter.
Figure 4.3: Saturated Stellar Image Showing Horizontal Smearing.
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