Something very unusual happened during the wee hours of September 7. Two different comets appeared to almost cross paths in the sky. Despite appearances, the two objects weren’t physically close. Comet 260P/McNaught is very much in the foreground at a distance of about 56 million miles, while the look-a-like Comet C/2018 N2 ASASSN glowed from 238 million miles, more than four times further away.
They appeared closest in the early morning hours, separated by 20 arcminutes or about two-thirds the width of the full moon. Observers with 8-inch or larger telescopes would have seen both comets in the same field of view — a rare sight. I wish I’d been looking. Instead my eyes were fixed on the constellation Cepheus and its treasure trove of star clusters and double stars.
I love comets both for their beauty and their ever-changing appearance. You never know what to expect night to night. Some comets break up into smaller comets, while others have “outbursts” and brighten suddenly. I’ve even seen comets crumble and fade to nothing.
A comet’s bright inner core, called the false nucleus (the real one, the actual comet is hidden in a dusty cocoon), can brighten or change color, while tails can grow and multiply. Compared to the unchanging constellations, comets are the crazy kids of the sky.
Over the past few weeks I’ve come across several other amazing celestial scenes appearing on Facebook and other sites. Everything from a night-shining clouds on Mars to the Earth and moon caught between the rings of Saturn. Some are old, some are new. Enjoy.