... Hickson Compact Group 90 . ... Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). ... Thor s Helmet (NGC 2359) and Planetary Nebula . ... The catch is, this lunar X is only apparent during a four hour period just before the Moon's first quarter phase. ... Although the phase of this moon might appear familiar, the moon itself might not. ... Crescent Moon and Venus . ...