This image by Martin represents the best output of several attempts at imaging Mercury in full daylight.  The elongation was favourable, with Mercury culminating before the sun and at a good altitude.  Several techniques had been used to find the planet in a bright sky, without any GoTo.  - using my 222mm Dobsonian on a home-built equatorial platform with Argo Navis digital setting circles and using the sun for error correction.  An improvised moveable sun screen held in a parasol base stopped slanting sunlight warming the inside of the tube.  The image represents the output of the best 0.75% of 334k frames, joined in Pipp then processed in AS3.0.11 and Registax using gamma and very light wavelets then finished using Astra Image deconvolution in PaintShop Pro.