So this weekend I read a little about the Dresden Codex of the Maya (their astronomical log) and played a little bit with Stellarium trying to imagine the sky they saw. I noticed something that I think is interesting, Venus wasn't very visible during the equinox every four years because the sunlight would cover it (from Mesoamerica). I looked for some information about it and found some tables of the Venus-Sun Conjunctions for several centuries, and conjunctions appear to take place around march an repeat about the same date every 4 years. http://www.astropro.com/features/tables/geo/ve-su/ve000su/vesu27.html For instance, Stellarium predict it won't be visible in 2013, 2017, 2021, etc. So, does Venus really "disappear" in the sky every 4 years during the march equinox?