Do I need to retake flats after camera rotation?

@soylentgreen66 That depends on what you mean with "camera rotation". If you mean "after a meridian flip where the camera keeps the same position with respect to the telescope" then no, you don't need to take flats and yes, APP will detect this and will apply the flats correctly. If you mean "the camera rotates with respect to the telescope" for instance when using a rotator or by manually changing the camera orientation then yes, you will need to retake the flats. For flats, the important aspect is whether or not the properties of the entire optical system have changed. In case of a meridian flip, those properties don't change. In case of removing the camera from the telescope and putting it back on or rotating the camera with respect of the telescope then the properties do change.

Hello thanks, I meant the latter. I rotate the camera orientation with a rotator to better frame the subject. OK, good to know that you need to take new flats everytime. Now, I'm curious how people with an alt-az style mount and a motorized derotator handles flats.

I'm guessing not really as the problem remains that the dust (for instance) rotates along with the rotation of the camera.

By "not really", do you mean that you can't use flats with an alt-az mount and motorized de-rotator or do you mean I don't need to retake flats if I rotate the camera orientation. Sorry, the way I phrased my 2nd question was unclear.

Well, that's why I also mention "I'm guessing". 😉 I never used an AltAz like that so it'll depend on what exactly it does. If the sensor is rotated in respect to the stars or the filters in front of the sensor, you need flats for almost every angle. If the entire system stays the same and only the stars rotate due to the entire system rotating the same, then you can keep using the same flats. A meridian flip doesn't change the system which is why you can keep using the same flats as well.