Venus Transit Applet
This applet is Dr. Scott's first attempt to actually
write his own applet all by himself.
[The phrase "all by himself" should be taken to mean that he
consulted numberous books on Java, bugged his brother Blair, his future
step-nephew-in-law, and LTU CS graduates {Colin}.]
Thus, this applet might not actually work properly!
(Doh!) It seems to require the latest Java for you to see all the
features. If you are having trouble, try updating your Java {I'll try to
post instructions on how to do that}, and until then, you'll have to just
live with the screen shots from the VenusTransit
screenshot page. Sorry about that!
But, if you are seeing the applet below properly -
great! We can have some fun with it. Some explanations are listed below
the applet. If you are looking for information about the Venus Transits -
see Dr. Scott's Astro Day 2004 presentation
(powerpoint).
Explanation of the controls:
- Individual transits - shows the transits
year by year (depending on the radio button choices)
- Series - all the transits that are grouped
in a 243 year cycle will be displayed (B is the only full cycle for the
years covered)
- Pairs - many of the transits occur 8 years
apart (our 2004 is mated with a 2012 transit)
- All vs May/June vs Nov/Dec - there are two
types of transits, when Venus is rising up above the ecliptic, or
sinking below
Time Span - the
calculations for these transits were made from the years -2000 to 4000.
So, some of the series died out during that time, and some are in
progress, and one will happen to start and finish during that timespan
(series B).
Suggestions for using the
applet:
- Run up and down the timeline with the
individuals ... run it fast by clicking the button repeatedly .. try
to look for "patterns" to the motion. [Will probably be hard
to find patterns, because they keep flipping angle up/angle down!]
- Try selecting either May/June or Nov/Dec ...
then run up and down the timeline. [Yes, when it happens to be a transit
that is not of the variety you picked .. the date shows in the box, but
no transit line shows. You are seeing the sloppyness of the programmer -
it is just easier to keep all the transits "together" and
always run up and down that chain {and just not print the transit line}
than to actually program it correctly. That might change in the future.]
With only one type of transit shown, it is easier to see the pattern
emerge - the transits are drifting up or down the sun. And if they drift
too far, the pairs become only singles .. and then back to pairs again.
- Try selecting the PAIRS button (and also
select either May/June or Nov/Dec - to limit us to the same type). Now
it is much easier to see the drifting of the transits, and the
destruction of the pairs. [Between two 8-year transits, they shift a
certain distance across the Sun - if that distance is too large, they
can't form a pair .. then you have singles.]
- Finally, take a look at the series (this
ignores the May/June and Nov/Dec radio buttons). Series B will be a
complete one (but is still in progress) - the other ones are still in
progress (B, C, E, and F) or are finished (A and D), but didn't start in
the -2000 to 4000 year span under observation
Want the source code for the applet?
Right click here, and use the "save as
..." option to download the Java code!
How did Dr. Scott make these calculations? Using
data/concepts from Jean Meeus's book "Transits" (he is an
astronomical god!).
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