Mars observational periods since the 2012 event up to 2028. Mars apparent angular diameter (left axis, black line) and planet declination (right axis, blue dashed line) mark the observational period of the planet. Minimums in the black curve show solar conjunction periods where no observations from Earth can be obtained. Dates of Martian oppositions when the planet shows a bigger size are highlighted. The last and next Mars oppositions are ideal for South and North hemisphere observers respectively. The connection with the solar activity is shown through the average number of sunspots (red line, red right axis). The high-plume event discussed in the text occurred in March–April 2012 (green vertical area on the left). The last and next Mars oppositions are shown in magenta and pink lines.