After a lot of fiddling with lenses and stray light I have finally made the adjustments necessary to reduce the diffraction spikes that have plagued the photos taken with my SkyWatcher Esprit 80ED refractor. By first removing the dew shield, a soft cloth glued around the lens chamber is revealed. Under the cloth, there are six screws around the lens chamber at one end and another six around the other. By unscrewing each of these an equal amount (about one full turn) using a hex wrench, the diffraction spikes seem to have vanished! However, when temperature goes far below 0 degrees C, they seem to be more visible again so my plan for the next winter is to unscrew the screws a bit more (if I dare 🙂 ).