** VERSION 0.9.9.406R CHANGELOG **

(1) – Terminal 5 (Lunar Eclipses) has been simplified. As some contacts adopt the same equation (P1,P4 – U1,U4 – U2,U3) I removed their duplicates. In addition, now a closest to 0 value of the functions is to be found, that’s the easiest way to locate the time of a contact. It’s possible to choose if Center of Mass or Figure of the Moon is applied to geometry of the eclipse so the results can be compared with Espenak’s predictions (the best available around, in my opinion), using COM.

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(2) – The Flag showing the geocentric radius of the Moon has been removed. I noticed that the slight distortion of the angular distances introduced by the stereographic projection is greater than this correction, so after looking for the approximate instant of a contact on the graphic map, the use of equations will still give the exact instant.

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(3) – MAIN WINDOW : The controls that change manually Longitude and Latitude are now linked one another. Inrementing 23′ 59″ now cause an automatic passage to 24′ 00″ and so on. This has to be intensively tested because in particular situations some bug can appear.

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(4) – Moon librations. Now Terminal 3 shows lunar geocentric and topocentric data about librations (optical + physical).

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(5) – Sun Physical Data. Terminal 1 shows conventional physical data of the Sun, L0, B0, P.

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(6) – UDC (User Defined Clock) LED doesn’t blink anymore. Now is simply ON or OFF.

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(7) – Sun and Moon now show their respective rotation axis.

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(8) – Code for Comets’ management is under test.

I would have liked to have been able to use the file generated by the JPL but strangely missing the information to estimate the magnitude of the comet (Absolute Magnitude and Slope parameter). So I chose the Minor Planet Center file (CometEls.txt). I noticed that it happens that for the same comet the two sources may report two slightly different orbits, which rarely leads the final result obtained by me to coincide perfectly with the ephemeris calculated by the Horizons system. Generally the difference is pretty small, about 3-5s in AR and a few arcseconds in declination, but it is there.

As an example we have :

Comet C2020 R4 (ATLAS) - 2021 06 15  12:00 TT (Elliptical orbit e = 0.9894)
 
 Uruk1 (Astrometric J2000 MPC data)
 AR = 10h 55m 15.061s
 DC = +18° 51’ 36.52”
 Mv = 17.79

 Horizons Platform (Astrometric J2000 JPL Data)
 AR = 10h 55m 20.97s
 DC = +18° 51’ 29.7”
 Mv = 17.679
 
 Injecting JPL Orbital Elements into URUK1 I obtain:
 
 Uruk1 (Astrometric J2000 JPL data)
 AR = 10h 55m 20.157s
 DC = 18° 51’ 31.95”
 Mv = 17.85

The residual is almost certainly due to the non-gravitational corrections applied by Horizons, which are ignored by me, but in this case the result would be much closer.

What can I say? I would certainly have preferred to use the JPL file but I don’t understand why they don’t publish values for the magnitude estimation.

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(9) Input Date Window. Since I am quite lazy and often have to deal with comparison dates of different ephemerides, tired of always resetting minutes and seconds I have included the possibility to quickly enter the values 0h, 6h, 12h, 18h in the Input Date window. 🙂

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(10) New files containing data about Asteroids and Comets (MPCORB.DAT and CometEls.txt) will be placed into the new folder USER_PATH/ExternalData, that will be automatically created at first run of the Application. The old files downloaded into USER_PATH can be deleted as they are no more used.

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(11) Comets Window – Identifying comets can be a little bit tricky because of their names, so I added a Search function.