Bob Moler's Ephemeris Blog

Ephemeris for Friday, October 11th. Today the Sun will be up for 11 hours and 12 minutes, setting at 7:05, and it will rise tomorrow at 7:54. The Moon, 2 days before full, will set at 6:24 tomorrow morning.

The interstellar comet 2I/Borisov, which was discovered August 30th by the Crimean amateur astronomer Gennady Borisov has given its first clues of its makeup. With data collected from the William Herschel Telescope in the Canary Islands the comet was discovered to give off cyanogen, a cyanide gas. This is just like what is given off by comets that belong to the solar system. As the comet comes closer to the Sun and warms up further more and different gasses will be liberated. It was the discovery of cyanogen in Halley’s Comet back in 1910 caused a panic because on that pass the comet’s tail swept past the Earth. However a comet’s tail is so tenuous that no cyanogen was detected in the Earth’s atmosphere.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Color photograph of 2I/Borisov. Image Credit: Gemini Observatory/NSF/AURA

Spectrum of 2I/Borisov. Top covers part of the visible and ultraviolet spectrum. The bottom zooms in on the CN emission. Credit https://arxiv.org/abs/1909.12144

10/09/2019 – Received word that C2 has also been discovered. This is also normal and can color the coma green. (I recorded the program on 10/06 illustrated this post on 10/07 due to being away due to my daughter’s surgery.)