261 Prymno is a somewhat large Main belt asteroid. It is classified as a B-type asteroid and probably has a primitive composition not unlike common C-type carbonaceous asteroids.
It was discovered by C. H. F. Peters on October 31, 1886, in Clinton, New York and was named after the Greek Oceanid Prymno.
References
The Asteroid Orbital Elements Database Minor Planet Discovery Circumstances Asteroid Lightcurve Data File
External links , Palmer Divide Observatory, B. D. Warner (2009) Asteroid Lightcurve Database (LCDB), query form (info ) Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center