Compilation of position angles (orientation)

Galaxies are not pure ellipsoids and therefore the position angles may varies with the considered surface brightness level. In some cases, this isophote twist may be very important, as for example in some spiral galaxies where a bar, seen at hight surface brightness, may be orthogonal to the outer disk. HyperLeda does not store information about the internal change of the position angle nor even information about the isophotal level where this quantity was measured.