Throughout history, comets have been looked upon by human beings as being great omens in the sky.  The long tails of comets were sometimes depicted in drawings as resembling swords.  Even as recently as twenty years ago, some people had odd perceptions of comets as portents of some great change.  Comet Hale-Bopp had such an effect in 1997.   Although comets have occasionally put on fantastic shows in the sky, Hale-Bopp of twenty years ago was the last widely visible comet, at least for northern hemisphere observers. of all the comets in the sky, there’s none like comet Halley.  We see it with the naked eye and periodically. Halley is, of course the most famous of all. We have recorded observations of Halley’s comet for over two thousand years.  Images of the comet can be found in paintings and drawings throughout history.  The Italian artist Giotto made a scientifically accurate rendition of the comet in his painting of the birth of Christ.  There are a couple of reasons why Comet Halley has become famous.  First, its orbit brings it near the Sun every 76 years, so there is a fair chance that you will see the comet sometime in your lifetime.  When Halley came by in 1986, it was not a very good show for us.  The apparition of 1910, in the other hand, was most impressive.  Earth actually passed through the tail of the comet which caused some panic here on Earth.  But as long as you had some anti-comet pills, you would be safe.    Right now, Halley's comet is slowly finding its way out past the orbit of Neptune, approaching aphelion.
Carpe Caelum Planetary Astronomy