The last couple of nights I've been perusing my limited collection of Review of Popular Astronomy magazines from the 1960's. I've particularly been attracted by the excerpts from Mallas' Observer's Catalog of Celestial Objects in the later issues. The catalog as far as I know has never been published in its complete form. The observations for the catalog and for the more famous Messier Album series in Sky and Telescope and the book of the same name were made with a four inch Unitron refractor. Mallas passed away in 1975. Does anyone know what happened to the 4 inch Unitron and if it survives, where it is today?