Venus Transit The last one of YOUR lifetime… Jim Wessel Johnson Space Center Astronomical Society

Transits occur at Conjunctions I suppose I should clarify that, and say inferior conjunctions. View of top of the Solar System Venus

½ 105 ½ Periodicity of Venus Transits Venus transits feature a repeating pattern every 243 years. At this time (2012), after a pair of transits, years will pass, then a first transit happens, then 8 years pass, then the second transit occurs. Then years pass, and the transit pair repeats.

Mercury Transits Orbits in 88 days. It’s inclination to the ecliptic is 7° (Venus is 3.4°, Earth is 0°). Mercury’s orbital eccentricity is.205 (compared to Venus at.006 and Earth at.0167). 1. Kepler’s laws vs. perihelion and aphelion. 2. Parallax

Historical Info: Ancient cultures (Greek, Babylonian, Egyptian, Chinese, Mayan) were aware of Venus as a planet, but did not mention transits. The first claimed observation of a Venus Transit was in 1032 by Avicenna. Babylonian Venus Tablet

1631 and 1639 Transits Johannes Kepler Pierre Gassendi Jeremiah Horrocks

1663 James Gregory

1716 Edmond Halley Concept stealer? Provided additional direction for Venus transit observation and timing.

1761 Transit Mikhail Lomonsov Map of the World, circa 1761 Venus, via Pioneer flyby, NASA

1769 Transit Lt. James Cook HMS Bark Endeavour, replica Map of Tahiti Point Venus Jérôme Lalande Fort Venus

Black Drop Effect

Simon Newcomb 1874 and 1882 Transits

2004 event

Head WEST, young man! A flat, western horizon is preferred. Texas Planning: < California< Hawai’i < TAHITI

Transit Times 4 Contact points (we’ll see 2…) First Contact Second Contact Greatest Transit = 5:09:38pm CDT = 5:27:34pm CDT = 8:29:36pm CDT 8:40pm 1st 2nd GT Sunset ~ 8:40pm

Where do you expect to observe the transit? Typically, western Texas has less clouds than Houston - Make your travel arrangements according to the level of risk you are willing to accept. Stay on top of the weather several days in advance Confirm your viewing method in advance. Use approved solar filters, pinhole projection, others… PRACTICE beforehand. Do you intend to record the transit? If so, how? Planning: Remember, this is 1x / rest of your life…

Solar Telescopes Coronado/Meade PST (Personal Solar Telescope) 40mm, F/10 $ Lunt LS35THa 35mm $ Coronado/Meade SolarMax II 90mm, F 8.8 $ Lunt LS80THa 80mm $

From personal experience, I can tell you these work nicely at a reasonable price point. But, they aren’t perfect… Solar Filters

If you intend to use a projection method, try it out in advance! Projection viewing

Practice with your system before the big day. 1 st class astrophotography setups can run several $K… Economic Imaging Equipment:

HIGHLY recommended

Even the Hubble Space Telescope is getting in on the act…

If you are clouded out… (Boo Hiss) Or Google search “Live webcasts of Venus Transit 2012” You chose… … Poorly.

Sources Cited: Wikipedia gal bucket oil funnel projector