Alert Notice 251: 1903-50 Supernova 1998dq in NGC 6754 AND Rare outburst of the TOAD-type cataclysmic variable 1626+21 V592 Herculis AND Fading of 1544+28A R Coronae Borealis AND Request for observations of 0409-71 VW Hydri and 0749+22 U Geminorum