Free downloadable items
A number of products from Rob Walrecht may be freely downloaded. For now there is only the quadrant, an instrument for measuring angles and thus heights (of towers, trees etc.). The quadrant is the predecessor of the sextant.
The quadrant is described extensively in our first (Dutch!) book: B01 - Genieten van de sterrenhemel ( Enjoying the starry sky ), that will be published in September or October 2006. See our product list. There are plans for an English version of this book.
Free item:
