panda

Thank you very much. I'm using ds9 to open it. See the attached image.

Hello, Dear all, I took a few images of the North American Nebula. Before mosaicing the images, I can correctly solve all the images. However, after mosaicing them with the image stiching mode, the solved image always has an incorrect rotation angle. I can always get a good solution, but just the angle seems incorrect. I attached one image before mosaicing and one image after mosaicing (cropped to remove the black edges) for your convenience to double check. What's the problem? Thank you very mu...

Thank you so much. Now I understand it is the hot pixels causing the problem. I can solve all the images now.

It is very strange that in most (although not all) of the cases I cannot solve the astrometry in ASTAP. I entered the expected position of the image or even the exact position. I also downloaded the G18 catalog. For example, in the attached files, the mosaiced image can be solved, while the cropped image cannot (the header contains the correct astrometry information). I also attach another unsolved image which should be not far from M57, the FOV of the image should be about 2.35 deg (height). The...