30 x 30 seconds, aligned and stacked to reveal the tail of Mercury. The Backdrop is a single 1-second exposure across Long Island Sound in the direction of Connectict.

A 4.4% waxing crescent Moon, and "comet" Mercury.

A 24 million km long plume of gas is ejected from Mercury's thin atmosphere due to the sun, very much like a comet.
This is only visible using a narrowband filter that captures the bright yellow sodium light at 589nm.