If you're planning on doing stuff like it on a regular basis (or just love cool kitchen gadgets) get a probe thermometer that you can leave in the meat that has a lead that runs out of the oven to the readout. I got a cheap one from Wally World for less than $20, and it works great.
The advantages to this are that you can check the internal temp of large pieces of meat without opening the oven or making a bunch of holes in your meat... And most of them have an alarm you can set for a specific temperature, which is great if you are doing something else at the same time...
Into the fires of forever, we will fly through the heavens, With the power of the universe we stand strong together
Through the forcing of power, we will soon reach the hour, For victory we ride, Fury of the Storm!