Four autograph letters from astronomer, Alexander Stewart Herschel [1836-1907] including two photographs. Dated between 1889 and 1893. The letters are addressed to Frank McClean [1837-1904] fellow astronomer. The first [four pages] mentions a paper by Dr Hasselbach in an Italian scientific journal on the subject of spectroscopic photography. He mentions that the paper was given him another astronomer, Mr. Piazzi Smyth. Four pages of a rather technical nature on the subject of spectrum photography. Slipped into the letter is a very small photograph with notes to verso explaining that it is an image of a lightning strike [much faded and not really discernible]. A PS further explains the background to the photo. The second letter [4 pages] profusely thanking him for McClean's solar Atlas, praising the work highly. Mentions a photograph [no longer present] of the scene around Slough. The third letter, dated October 1893, four pages, hoping to arrange a visit to Rusthall [McClean's home and observatory in Tunbridge Wells]. Included here is a photograph showing a 'curious case' of reversal of the sun and its reflection with details written to verso of the photo. The fourth letter [4 pages] dated two days later than the previous letter, firming up his arrangements to visit Rusthall. One letter with some spotting else good condition. A very nice series of letters from Herschel, scion of a great astronomical family.
Author Alexander Stewart Herschel, astronomer