U Monocerotis
At the Top of its Class
U Monocerotis is an interesting and bright RV Tauri-type variable. Fluctuating between visual magnitude of about 5.1 - 7.1, U Mon is seen to exhibit two periods: a short-term and a long-term period of about 92 and 2475 days, respectively (Percy et al. 1991). The first observations of U Mon date back to the 1870s (Percy et al. 1991), however, the variable has only been monitored continuously by AAVSO observers since 1945.