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Glossary:

Transit

Passage of a planet in front of the disk of the sun. These rare events have an important historical importance in calculating the distance sun-earth. Transits can only be observed with properly equiped telescopes. By no means try to observe these event without being trained! You may damage your eyes.

Partial eclipse begins/ends

First and fouth (last) contact. The much smaller disk of the planet starts entering the bright solar disk. This is a partial solar eclipse.

Umbra eclipse begins/ends

Second and third contact. The apparently small planetary disk seems to hoover in front of the sun, completely detached from the border of the limb. This corresponds to the begin/end of an annular solar eclipse.

Maximum eclipse

Gives the object name (Venus or Mercury), and time and phase of maximum eclipse, i.e. possible phases are partial or annular eclipse. With the later, the planetary disk is apparently floating as small dot across the disk.

ET-UT1 / deltaT

Frictional forces from the moon, sun, etc slow down the rotation of the earth over time. Our civil clock (UTC) is kept in sync with the rotation of the earth by inserting leap seconds, and thus UTC varies unpredictably from the time kept by atomic clocks and the motions of the solar system (ET or TDT, Terrestrial Dynamic Time). The difference between ET and UTC (or, more properly, UT1) is deltaT, currently a little over one minute.
For eclipses and transits, the events take place with calculations based on TDT. Relating them to fixed points on the earth (latitude/longitude) is done by estimating the time difference deltaT. When the estimate is off, the predicted site on earth is not at the place where the eclipse is taking place. Values from several milleniums ago can be reconstructed by evaluating historical records of e.g. solar eclipses. CalSky uses for the period from 1630 to now measured values published in the Astronomical Almanac and by IERS. Back to the year -500 points from F.R.Stephenson ('Historical Eclipses and Earth's Rotation' 1997) are used (table 14.1, Spline interpolated). Prior to -500 and for the future, approximation funcations for the length of day are integrated. Those function are based on Figure 14.7 from Stephenson (1997). Calculated values outside the telescopic era can be off by several percents.