Not urgent!

I wish for a few improvements of the ephemeris visualization in AstroCalc.

• Being able to change the symbol of the marking. E.g. a cross, a star, a ring, general comet symbol etc.
• Being able to show markings only when labled. This means that I can choose to show e.g. Hale-Bopp's position from 1997-01-01 to 1997-12-31, with 1 day intervals, but only show the markings at e.g. 10 day intervals. This means the line keeps smooth, but without markings in every breaking point. See this image for a suggestion:
  https://upload.wikimedia.org/wikipedia/commons/f/fc/Comet_Hale-Bopp_starmap_1997.png
• Being able to use more customizable labels. For example, I would like to show only day and month, or year and month, or just day and hour.
• Perhaps some antialiasing of the lines and symbols?