I am trying to calculate an NDVI over time (say, the span of 30 years) for a certain area of the United States. I think it's possible with Landsat 5,7, and 8 together. The goal is to understand change in peak vegetation over time to evaluate the efficacy of natural parks policy in a certain locality.
Question: If I were to download images from 5,7, and 8 and calculate NDVI, would the results be comparable between satellites? If they are not, is it possible to make transformations to make them comparable?