I am using the Tufte-style book document class and I would like to place a margin figure at the very top of the margin (there are no other figures in the page). I do this with the \begin{marginfigure} command. As is, it places the figure around the place I insert it. There is an argument which can be negative but it requires me to indicate the specific amount in centimeters, inches, etc. I don't want to be guessing how far the top is from where the image begins. Is there a way I can easily indicate for the figure to be at the top? maybe a variable that "knows" what my current y coordinate is and i can set the offset to -\ycoor? The usual parameter "t" for figures does not work in marginfigures of the tufte book. Please help!
Here is a simple working example. I have used \sidenote so as not to insert a figure but they work the same. The second argument (which i made -1cm) is the offset:
\documentclass{tufte-book}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\lipsum[3]
\sidenote[][-1cm]{this is the sidenote, i want it to be at the top of the margin}
\end{document}
