Re-creating the dew cap

The telescope was missing its dew cap when it arrived at the Museum. The cap attaches to the end of the telescope tube and is closed with a lid when the telescope is not in use to prevent moisture condensing on the objective lens. To design a replacement dew cap, the conservation team took measurements from a photograph of the telescope from around 1906 and gathered information about the cap’s size and style from an illustration in the telescope manufacturer’s sales catalogue from the 1880s. A new cap and cover were manufactured out of brass and then ‘aged’ to match the original brass parts of the telescope.