gr1 = ListPlot[baseplateTemp2, Joined -> True,
  ImagePadding -> {{110, 30}, {5, 42}}, ImageSize -> Full,
  AspectRatio -> .18, Frame -> {Left, Top, Right},
  PlotRange -> {{first, last}, {-40, 80}},
  FrameTicks -> {{Automatic, Automatic}, {Automatic, topaxis}},
  BaseStyle -> {FontSize -> 14},
  FrameLabel -> {{"Baseplaten Temperature, [Degree] C", ""}, { "",
     "Time Offset, Days"}}, GridLines -> {botax, Automatic},
  Axes -> None]