Correspondence regarding solar photography at the Royal Observatory. There is an index listing the following sections:
1. 'Photos to complete the Greenwich Series': correspondence with the Solar Physics Observatory, South Kensington, and the Trignometrical Branch, Survey of India, Dehra Dun, India, comprised mainly of requests for the supply of photographs to fill the gaps where no photograph was taken at Greenwich due to the weather conditions. There is also correspondence between E.W. Maunder and the Solar Physics Committee regarding defects in the Indian photographs, December 1886.
2. 'Indian Photographs - correspondence with the Trigonometrical Survey Department, Dehra Dun'. The topics include the type of plate to be used at Dehra Dun, with a formula for the development of gelatine plates. There are also two unsigned memoranda regarding errors in the times recorded on Dehra Dun plates.
3. 'Correspondence with Mr Lockyer relative to reduction of India photographs'. The principal topic is the work involved in the examination, measurement and reduction of Indian sun pictures.
4. 'Tables and numerations of spots communicated to Mr Lockyer - Correspondence on the transference of Greenwich duplicates to South Kensington'. The main topic is the numbering of various spot groups. There are also lists of Greenwich duplicate photographs sent to South Kensington.
5. 'Observations given': correspondence with various individuals on matters concerning sunspot numbers.
6. 'Correspondence with Dr Hasselburg, Dr Huggins, Professors Pickering, McCleod and Stokes'. The correspondence includes the circular 'Astronomical Photography' by E.C. Pickering and Professor McCleod of Montreal on starting solar photography.
7. 'Publication of the Kew Sunspot Observations', comprised mainly of correspondence with A.L. Soper regarding the best method for publication of the Kew results, to be undertaken by W. De La Rue.
8. 'Transparencies of spot groups sent to Father Perry': correspondence with Father S.J. Perry regarding the lists of sunspot pictures sent to him.