Mercury, however, is NOT a comet. It is beyond unlikely that it contains any frozen volatiles. It has been too close to the Sun for way, way too long. So, this tail has to be dust being blown away from its surface by Solar winds. Neat. Mercury, at best, naked eye, is but a small, faint spec. A dot. Very unlikely you would see this tail naked eye. But, try to get a gander. The above map should help.
Check Category ‘Astronomy’.