Two sun filters, one dark green glass, the other smoked glass, in rectangular slide mounts for use on a telescope. Both glass filters are either cracked or blistered due to the effects of their use on the sun. Inscriptions indicated that they were used at the Royal Observatory, Greenwich and the observatory of Captain W.H. Smyth RN, at Bedford, England. It is likely that they were originally in the possession of Smyth due to his association with the United Services Institution. Two optical Sun filters 1824-1844
Smoked glass sun filter (soot missing) in brass slider mount for use at the eyepiece of a telescope unsigned, English, 1824-1831. Inscription indicates that the glass was cracked whilst observing the sun using the 9 feet telescope (see 1929-949) at the observatory of Captain W. H. Smyth at his Bedford Observatory, England around 1831. It is likely that it was originally in the possession of Smyth due to his association with the United Services Institution. Smoked glass Sun filter in brass slider 1824-1844