50 years of RGU photometry.
50 Years of Soviet Astronomy
50 years of the Moscow astronomical olympiade.
50-year Analysis of Jupiter's DAM Radio Sources
500 K and Below - Finding Ultracool Dwarfs with the UKIRT/WFCAM and VISTA surveys
500 TeV gamma rays from Hercules X-1
500 to 3000 A Observations of the UX UMa Stars V3885 Sgr, RW Sex, and IX Vel
500 Years Since the Death of Bernard Perger. (Slovenian Title: Ob petstoletnici smrti Bernarda Pergerja)
500-3200 A observations of the interacting binary stars V356 SGR and Beta LYR
5000 MHz flux densities and spectra for 325 small-diameter radio sources at low galactic latitudes
5000 MHz source counts at 105/sr.
5000 Web Students Later: Panacea or Curse?
50th anniversary of Dundee Astronomical Society
51 Eri and GJ 3305: A 10-15 Myr old binary star system at 30 parsecs
51 NEMAUSA
51 neue Veräderliche
51 Ophiuchi (B9.5 Ve) - A Be star in the class of Beta Pictoris stars?
51 Ophiuchus: A Possible Beta Pictoris Analog Measured with the Keck Interferometer Nuller
51 Pegasi
51 Pegasi