Guillaume Bigourdan discovered IC 2605 = Big. 402 on 11 Apr 1899 while observing NGC 3395. According to Harold Corwin, Bigourdan commented, ""Nebulous rounded object, about 20 arcsec across, it would be nearly impossible to make measurements." and estimated an offset of 0.5 seconds of time west and 17" south from the nucleus. Corwin identifies this with the brighter inner spiral arm just south of the core of the galaxy.

The identification of IC 2605 as part of the arm of NGC 3395 was made by Francis Pease in his 1920 paper on descriptions of nebulae photographed with the 60-inch at Mt. Wilson.

900/1200mm - 48" (5/4/16): this number refers to the brighter southwestern spiral arm of NGC 3395. This inner arm was fairly easy and well-defined on the south side of the galaxy; it rotates sharply counterclockwise nearly 180°, ending on the east side of the galaxy.

Notes by Steve Gottlieb