Mercury is the small black disc on the left of the image of the Sun. There were no sunspot groups. Seeing poor. Altitude 13°. The next transit of Mercury will occur on 13th November 2032, this will be partly visible from Ireland.
85 mm refractor at 600 mm focal length. 11th November 2019 at 12.49 UT.DSLR with 1/750 s exposure. Thousand Oaks Type 2+ Solar filter used. From Rush, Co Dublin.
Mercury is the small black disc crossing the sun towards the bottom of the image. Note the sunspot groups. Transits of Mercury are much more frequent that those of Venus.
106 mm refractor operating at about 850 mm focal length. 9th May 2016 at 13.02 UT.DSLR with 4x 1/750 s exposures. Thousand Oaks Type 2+ Solar filter used. From MA, USA.
Left: Venus entering the solar disc. Time 22:23 UT. Detail from full frame. 1/250 second.
Middle: Venus has now entered fully on the disc of the sun. It appears very much darker than the umbrae of the sunspots present.1/200th of a second exposure taken at 23:03 UT.
Right: Animated Gif of 8 frames from the Transit. 
5th June 2012 from the shores of Lake Champlain, Vermont, USA. Taken through a 70 mm refractor (Pronto) at an effective focal length of 528mm. DSLR camera at ISO 400. Thousand Oaks Type 2+ Solar Filter used.
This was the last Transit of Venus for 105 years!
Venus is the small dark disc crossing the sun. Transits of Venus are very rare events, this was the first transit of Venus since 1882. The next one occured on 6th June 2012.
8th June 2004 from Crete.Taken through a 420 mm Telephoto Lens on Kodak Elite Chrome 100. 1/125th of a second exposure. Solar Filter used.
Mercury is the small dark dot crossing the sun towards the top of the image (the other spots are sunspots). Transits of Mercury are much more frequent that those of Venus. However,as the sun is frequently below the horizon from Ireland, this was the first one visible from there in nearly thirty years. The next one (that was visible from Ireland) occured on 9th May 2016.
70 mm refractor (Pronto) operating at x4 its focal length giving 1920 mm. 7th May 2003 at 07.55 UT.Fujichrome 100 slide film. Solar filter used. From Dundrum, Dublin.