The amount of object to be imaged that you can fit on the chip depends on the size of the chip, the size of you pixels and the focal length of your telescope.
Based on a 400mm FL, a 1280x1024 chip with 5.2 micron^2 pixels the sun through the pst with the SAC 4.2 mono should look like this picture below.
From memory it is a bit tighter fit than that, but I'll experiment and let you know.
edit: While SAC don't let you easily find out on their site, the SAC 4.2 is a CMOS chip not a CCD. But it is an 10 bit chip, the DMK is only 8bit so you get a doubling of tonal range (theoretically
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