File:Sunspots seen by azimutal observer during day.gif

English: Earth rotation is responsible for rotation of image plane when observed by azimutal mounted telescope or simply observed by looking at sun (through protecting glass). The image simulates the rotation from morning till evening. Rotation angle was calculated according (thanks to Rolf Hempel, 2024):

Tubas (talk) from math import sin, cos, asin, acos, radians, degrees, pi

def equatorial_to_azimuth(rect, decl, sideral_time, latitude):

   """
   Convert equatorial coordinates in azimuthal ones.

   :param rect: Right ascension of the object (in radians)
   :param decl: Declination of the object (in radians)
   :param sideral_time: Sideral time (in radians)
   :param latitude: Geographical latitude of the observer
   :return: azimuth, height, position angle with:
            azimuth: equatorial azimuth angle of the object (in radians)
            height: equatorial height of the object (in radians)
            position angle: rotation of northern direction relative to vertical at the object
                            (in radians), positive in clockwise direction
   """

   h = asin(sin(latitude) * sin(decl) + cos(latitude) * cos(decl) * cos(rect - sideral_time))
   dir_from_south = (rect - sideral_time + 2. * pi) / (2. * pi) % 1.
   if dir_from_south > 0.5:
       P = acos((sin(latitude) - sin(h) * sin(decl)) / (cos(h) * cos(decl)))
       az = 2. * pi - acos(
           -cos(P) * cos(rect - sideral_time) + sin(P) * sin(rect - sideral_time) * sin(decl))
   else:
       P = - acos((sin(latitude) - sin(h) * sin(decl)) / (cos(h) * cos(decl)))
       az = acos(
           -cos(P) * cos(rect - sideral_time) + sin(P) * sin(rect - sideral_time) * sin(decl))
   return az, h, P

if __name__ == '__main__':

   rect = radians(180.)
   decl = radians(0.)
   latitude = radians(50.)
   sideral_time = radians(90.)

   azimuth, height, position_angle = equatorial_to_azimuth(rect, decl, sideral_time, latitude)

   print("Azimuth: " + str(degrees(azimuth)) + ", height: " + str(
       degrees(height)) + ", Rotation of north relative to vertical: " + str(degrees(position_angle)))

Tubas (talk)

The image is based on photo taken by Rolf Hempel, see: File:Hempel 2024-08-24 08-14-10MESZ Sonne.jpg, animation done by Tubas