應該是很肯定軟體錯了
NASA最新的資料是0.001度應該是正確無誤
模擬冥王星的恆星日大約6.3個地球日
而Charon兩次中天只要3.1個地球日
再次確定軟體模擬冥王星自轉與Charon公轉是反向，因此只要半個冥王星自轉周期就會再次見到Charon過上中天
有用的觀念澄清網頁:
http://www.mira.org/fts0/planets/101/text/txt201x.htm其中有些好問題
值得思考
與適合用來施考(出題):
The fact that Charon was not discovered until 1978 (see below) means
that the determination of the rotational and physical parameters of Pluto and its moon
are
still imprecise.
As Uranus, Pluto's axis of rotation is tilted and points nearly directly to the Sun. The seasons on Pluto are therefore similar to those of Uranus. Likewise, Pluto's rotation is retrograde, meaning that if you were to view Pluto from above the ecliptic (north direction from Earth), it rotates in the opposite direction as the other six planets (remember that Uranus and Venus are the other planets that have retrograde rotation).
Pluto is so distant that only the best ground-based pictures or the Hubble Space Telescope can resolve Charon.
The tilt of Pluto's axis of rotation is about 112° and was measured by the tilt Charon's orbit around Pluto, which should coincide roughly with Pluto's equatorial plane. Thus, you must visualize Pluto going around the Sun with Charon's orbit around Pluto nearly perpendicular to Pluto's orbit around the Sun. At the same time, Charon's rotation period is synchronous with its orbital period, and synchronous with Pluto's rotation period. Thus, visualize Pluto and Charon always facing the same way to each other.
Imagine yourself on the surface of Pluto facing directly toward Charon. Where would Charon be on your sky throughout your Plutonian year? Where would the Sun be on your sky throughout your Plutonian year?
Would you see phases of Charon? Approximately how long would your day-time and night-time (or bright-time and dark-time) last? Now picture yourself near Pluto's north or south pole and answer the same questions.
What if you are on Charon's surface? If you are mathematically inclined, you can even calculate the angular size of Charon as seen from Pluto,
or Pluto's angular size as seen from Charon.As seen from Earth, the orientation of Charon's orbit changes as Pluto orbits the Sun. Twice during Pluto's sidereal period, Pluto and Charon occult each other.
觀星相簿 
