test 1 Astronomy - May 2018 USA | Page 56

Above: An obliquely oriented spiral, NGC 3521 is one of the most overlooked bright galaxies in the sky. A small scope shows it as a beautiful cloud of light. KEN CRAWFORD discover and share. Skilled deep-sky observers are renowned for seeing what used to be deemed impossible, and I have faith in them. Observers can easily overlook Leo’s dis- crete southern extension, which contains some interesting galaxies. Chief among them is NGC 3521, one of the most neglected bright galaxies in the night sky. This 9th-magnitude marvel rivals many of the Messier galaxies. Through a 4-inch scope, this oblique spiral spans 12' by 6.5', is oriented northwest-southeast, and appears cometlike — similar to an ellipse within an ellipse. It is classified as a floc- culent spiral (like NGC 2841 in Ursa Major) with extensive debris shells that surround the galaxy’s disk like a toy in a bubble bath. This is yet another stunning example of a galactic cannibal, where the sloppy remains of several long-deceased satellite galaxies still surround a voracious spiral. While much of this drama is invis- ible to the eye, I do wonder if the brightest patch of the slaughter — just northeast of the nucleus — can be spied in large ama- teur telescopes. Rings and things Leo’s most famous gaggle of galaxies is undoubtedly the Leo Triplet, consisting of 56 A ST R O N O M Y • MAY 2018 two 9th-magnitude spirals, M65 and M66, joined by the slightly fainter edge-on spiral NGC 3628 (the Hamburger Galaxy). Located about halfway between Theta (θ) and Iota (ι) Leonis in the big cat’s thigh, this winning trio travels as a pack at a dis- tance of about 30 million light-years. All measure about 10' in length, can be spied even in 10x50 binoculars under a dark sky, and telescopically display the deforming effects of tidal warping. Telescopes as small as 4 inches can reveal the “broken arms” of M65 and M66, but the most amazing and concealed fea- ture of the group is a striking tidal “plume” trailing off NGC 3628. This extragalactic umbilical cord of star-forming regions extends some 2˚ east of NGC 3628’s north- eastern rim before arcing slightly to the north, making the galaxy appear like an old westbound ocean liner trailing smoke. Lenses as small as 200 millimeters have been able to capture this tail. The question is: Can it be seen visually? And if so, at what aperture and magnification? Return your telescope to Regulus. Now