Is it hard to tune the gyro because its accuracy is too low, or because it's accurate to begin with but degrades over the course of the long exposure? Is a pur

Is it hard to tune the gyro because its accuracy is too low, or because it's accurate to begin with but degrades over the course of the long exposure? Is a pure software solution even reliable enough under these conditions? Slowness can be worked around by doing it in the background, and you get a notification when it's complete. Some people would be okay if that's the only way to get photos they wouldn't otherwise be able to get, short of buying an SLR.