Requiem for Relativity

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />Dr Joe, Why not report this Baghdad event to JPL and see how they explain Venus being observed one degree from the location their generator shows it to be? I would go with the observation assuming it was writen down at the time of the event because as good as the the JPL generator is it has its faults.
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Hi Jim!

Thanks for the suggestion. Here we have the written record [by Ibn Iounis, cited in Robert Newton's book] disagreeing both with JPL's program and with Bob's Stellarium. [edit Nov. 17: I rechecked my work, which had been based on the JPL Mars and Venus ephemerides and the time-dependent Mars orbital elements, and found complete agreement with Stellarium.]

A website, www.bogan.ca , "List of Mutual Planetary Occultations" (cites Albers, Sky & Telescope, March 1979 for the 1557-2230AD part of the list) misses both the recorded 1590AD and the recorded 864AD Venus-Mars occultations. At least JPL [and Stellarium] found the 1590AD occultation spot-on, and Bob's work with Stellarium [and mine with JPL, now] finds the 864AD occultation, though a few days off.

- Joe

Dr Joe, The generator at JPL is a model focused on the Earth/Moon barycenter as best I can determine. I don't have the mathematical background to really understand what better model might be used but I do know the Earth/Moon barycenter does not move around around the sun in an elliptical orbit as is assumed by the people who made the generator. I figure that is reason for the small error in the numbers the generator produces. Maybe you with your strong background in math could do something to correct this problem at the source by pointing out errors like the Baghdad occult. I'm sure there are more like this one if anyone looked.

Stellarium shows a occultation of mars and venus at Heidelberg on Oct. 13th 1590 at about 5 a.m. That looks right as Germany, a protestant country, remained on the julian calendar for some time, so a ten day error.

Sloat, Can you report this to the guys at JPL? I tried to point out an error in their generator several years ago but never had solid data like you found. The JPL staff are nice people and I found them to be quite helpful explaining how to do set ups but had no luck pointing out error caused by a faulty model-I'm not diplomatic and like anyone they have short fuses when it comes to issues like this.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Stoat</i>
<br />Stellarium shows a occultation of mars and venus at Heidelberg on Oct. 13th 1590 at about 5 a.m. That looks right as Germany, a protestant country, remained on the julian calendar for some time, so a ten day error.
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Hi Bob,

Thanks for the additional information. I rechecked and confirmed my work on this occultation, which had been based on the JPL Venus and Earth ephemerides and the Mars orbit; it had to be the AM of Oct. 3rd, 1590 in the Julian calendar, which the Protestants were still using, and that was Oct. 13th in the Gregorian calendar then. I guess Stellarium uses the Gregorian calendar, at least for dates after the Gregorian reform.

- Joe

Dr Joe, All the orbital calculations are based on the JPL generator as noted at all the sites posted so far. JPL has a better way of dating that I don't understand but you might like better than calender dates. You can ask JPL how it works-I don't have any idea how useful it might be.