I was looking all over for a graphic on the Mars encounter last Thursday and NASA published this on Friday. Great timing! So now I need to figure out if the comet might be visible with a telescope. Could be, the moon won’t be a factor and Mars should be visible for a time after sunset. I just need to upload the ephemeris for Siding Spring into Stellarium.
One thing I will be able to see (and so will you) on that night is Venus and Spica very close together — easy to see too. More about that later on.
NASA on the visit:
NASA is taking steps to protect its Mars orbiters, while preserving opportunities to gather valuable scientific data, as Comet C/2013 A1 Siding Spring heads toward a close flyby of Mars on Oct. 19.
The comet’s nucleus will miss Mars by about 82,000 miles (132,000 kilometers), shedding material hurtling at about 35 miles (56 kilometers) per second, relative to Mars and Mars-orbiting spacecraft. At that velocity, even the smallest particle — estimated to be about one-fiftieth of an inch (half a millimeter) across — could cause significant damage to a spacecraft.