Roberts discovered 33 IC objects by photography, using the 20" reflector at his observatory "Starfield", Crowborough Hill, Sussex, UK. Of these, 29 are real deep sky objects. Some were found also by Frost and Wolf later. Occasionally IC 4703, the Eagle nebula in M 16, is credited to Barnard (1895), but there is no hint for this statement. It is clear, that Roberts has photographed the M 16 region in 1894 and 1897 (see MNRAS 55, 223 (1895); 56, 380 (1998)).

 

References: [1] Photograph of a "New" Spiral Nebula in Perseus, MNRAS 54, 371 (1894); [2] Photograph of the Nebula H VI.41 and a new Nebula in Draco, MNRAS 56, 32 (1895); [3] Photograph of the Cluster H VIII.76 and of a new Nebula in Cygnus, MNRAS 56, 33 (1895); [4] Photograph of the Nebula H IV 75 Cephei, MNRAS 56, 380 (1896); [5] Nebulae unrecorded in the Catalogues, AN [3429] 143, 341-344 (1897); see also: Obs. 20, 244-246 (1897); [6] Nebulae which are not recorded in the Catalogues, AN [3509] 147, 87 (1898); [7] On a region in Lynx rich in nebulae, AN [3857] 161, 301 (1903); [8] On the Nebula h 2302 N.G.C. 7822 Cassiopeiae; the Region surrounding H II. 457 N.G.C. 1665 Eridani, with ten new nebulae; and H III. 558 N.G.C. 7492 Auqarii, MNRAS 63, 301-302 (1903)

The galaxy IC 2099 in Eridanus, credited to Roberts by Dreyer (found Feb. 2, 1903; Ref. 8), is identical to NGC 1677, discovered by Lewis Swift in 1886.

Obituary: MNRAS 65, 345 (1905); PASP 16, 228 (1904); Proc. Roy. Soc. 75, 356 (1905); AN 166, 63 (1904)