Free Astronomy Magazine March-April 2022

ASTRO PUBLISHING for a specific in- stant. The solar graph allows you to view the az- imuth and height of the Sun during the year based on the time, and to superim- pose a horizon mask on it to predict the times in which obstacles will put the observer (or the sundial) in the shade. This tool is used by architects to optimize the orientation of the rooms in a house. Amateur astronomers may be interested in ephemeris, but also in the map of the sky, drawn according to place and time. In short, many features of educational or practical natures are available. Finally, we recall the other unique feature of Shadows: its ability to simulate three types of astrolabes on the screen, including the superb planispheric as- trolabe, all elements of which can be config- ured and manipulated by mouse. The program also provides a very simple way to make a functional astrolabe. The software can be downloaded from https://www.shadowspro.com. Its ba- sic version is free. It comes with a complete and illustrated user man- ual in PDF format, allowing you to discover all of the features and to understand gnomonics. Interested amateurs can then upgrade to the Shadows Expert or Shadows Pro levels by purchasing a license at a low price ( 23 or 57 USD ). Amateur astronomers who spend their nights observing and photo- graphing the deep sky can remain in contact with the stars and celestial me- chanics by taking an interest in sundials and astrolabes during the day or when the weather conditions are not favorable – providing another topic of interest and won- der of human intelligence in the face of the richness of the universe. O n the right, the face of a plani- spheric astrolabe, with its spider and movable ruler. Below, the back of the astrolabe, with the alidade and the square of shadows. ! MARCH-APRIL 2022 49