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** VERSION 0.9.9.374R CHANGELOG **

As previously said I decided to push momentarily the brake pedal and think about what has been done so far rather than adding new features.

I couldn’t ignore the brilliant work (2020) of F.R. Stephenson about new determination of DeltaT values in the period from 709 BCE to 1600 CE, so I included those values into my DE441 recalibration (RC), comforted by the fact that this time Stephenson claims to have used DE431 as a reference ephemeris. At the epoch he examined the difference between DE431 and DE441 is negligible. For years preceding 709 BCE the tax of reliability drops considerably as I rely on more uncertain sources up to the most ancient total eclipses reported by Prof. Göran Henriksson of Uppsala University (3000 – 3600 BCE). All this because it seems to me that the simple parabolic function proposed by NASA and others is not able to reproduce non-tidal effects of the DeltaT variation. But at this point the speech would be very long so let’s see what’s planned for the next version.

1A. BUG : when a manual variation of Longitudine or Latitude of a site caused a switch to “Manual Entry” the linked horizon profile was not unloaded. SOLVED.

1B. BUG : if DE441 is not installed inserting a date out of the domain of DE440 causes a loop of error windows. SOLVED.

1C. BUG : when Windows 10 is configured (Screen Menu) to show everything magnified of 125% some controls are not shown correctly. This problem should be disappeared.

1D. BUG : HORIZONTAL VIEW: when a ‘N’ ‘S’ ‘E’ ‘W’ button is pressed the Zoom Control and the Graphic Screen Zoom value are not synchronised. SOLVED.

2. ECLIPSE FINDER: now the search for local solar eclipses is more restrictive. Eclipses, total or partial, whose maximum is more than -2° (previously -10°) of altitude are discarded.

3. INFO MENU: added a window showing all the DeltaT Calibration Points used by the Recalibration (RC).

4. CANON OF LUNAR ECLIPSES: internal calculations are now more accurate. Values of Gamma an U computed by means of Meeus’ algorithms contain a truncated series of long term values so I bypassed this problem using a DE441 recomputing. Also I switched from Danjon to Chauvenet model.

5. DELTAT (RC). Reworked, as said above. These are the new Calibration Points currently used. 

 No.    JDN TT        Julian Date TT                                                    DeltaT(sec)
 CP001  +0387450.786  TSE Eshnunna TT 3653 Oct 13 BCE                                   +095730.00
 CP002  +0536491.812  TSE Knowth TT 3245 Nov 01 BCE                                     +083685.00
 CP003  +0572726.117  TSE Knowth TT 3145 Jan 15 BCE                                     +081500.00
 CP004  +0651749.965  TSE Eshnunna TT 2929 May 24 BCE                                   +074050.00
 CP005  +0752271.580  TSE Khafaje TT 2654 Aug 11 BCE                                    +065325.00
 CP006  +0818981.447  TSE Khafaje/Babylon TT 2471 Apr 01 BCE                            +061525.00
 CP007  +0933028.435  TSE Akkad(Baghdad) TT 2159 Jun 29 BCE                             +051007.00
 CP008  +1042557.602  TSE Babylon TT 1859 May 15 BCE                                    +044200.00
 CP009  +1138561.269  TSE Ekemberg TT 1596 Mar 18 BCE                                   +037275.00
 CP010  +1152617.256  TSE Babylon TT 1558 Sep 11 BCE                                    +036450.00
 CP011  +1181735.103  PSE 99% Thebe Egypt TT 1478 Jun 01 BCE                            +035650.00
 CP012  +1219327.032  PSE 98% Ugarit TT 1375 May 03 BCE                                 +032800.00
 CP013  +1232852.370  TSE Amarna TT 1338 May 14 BCE                                     +032300.00
 CP014  +1235804.983  PSE 97% Anyang TT 1330 Jun 14 BCE                                 +032200.00
 CP015  +1272364.166  TSE Ekemberg TT 1230 Jul 18 BCE                                   +031400.00
 CP016  +1274786.315  TSE Ugarit TT 1223 Mar 5 BCE                                      +031300.00
 CP017  +1292120.232  PSE 94% Anyang TT 1176 Aug 19 BCE                                 +029200.00
 CP018  +1308598.252  TSE Gaza TT 1131 Sep 30 BCE                                       +027900.00
 CP019  +1442903.057  TSE Nineveh/Nimrud TT 763 Jun 15 BCE                              +022975.00
 CP020  +1462659.060  TSE Qufu TT 709 Jul 17 BCE                                        +020700.00
 CP021  +1484837.057  TSE Thebes TT 648 Apr 06 BCE                                      +019190.00
 CP022  +1506866.432  ASE Thasos TT 588 Jul 29 BCE                                      +018200.00
 CP023  +1507900.376  TSE Thasos TT 585 May 28 BCE                                      +018130.00
 CP024  +1543424.870  PSE Thebe TT 488 Sep 01 BCE                                       +016610.00
 CP025  +1546881.116  ASE Thebe TT 478 Feb 17 BCE                                       +016470.00
 CP026  +1552432.235  TSE Thasos TT 463 Apr 30 BCE                                      +016250.00
 CP027  +1564215.347  ASE Khultepe TT 431 Aug 03 BCE                                    +015790.00
 CP028  +1577740.031  ASE Tarsus TT 394 Aug 14 BCE                                      +015270.00
 CP029  +1608421.945  TSE Chaeronea TT 310 Aug 15 BCE                                   +014100.00
 CP030  +1652953.872  TSE Rome TT 188 Jul 17 BCE                                        +012825.00
 CP031  +1721057.500  CE 1 Jan 01 - HM Nautical Almanac, UK 2020                        +010440.00
 CP032  +1757582.500  CE 100 Jan 01 - HM Nautical Almanac, UK 2020                      +009410.00
 CP033  +1794107.500  CE 200 Jan 01 - HM Nautical Almanac, UK 2020                      +008420.00
 CP034  +1830632.500  CE 300 Jan 01 - HM Nautical Almanac, UK 2020                      +007480.00
 CP035  +1867157.500  CE 400 Jan 01 - HM Nautical Almanac, UK 2020                      +006540.00
 CP036  +1903682.500  CE 500 Jan 01 - HM Nautical Almanac, UK 2020                      +005590.00
 CP037  +1940207.500  CE 600 Jan 01 - HM Nautical Almanac, UK 2020                      +004650.00
 CP038  +1976732.500  CE 700 Jan 01 - HM Nautical Almanac, UK 2020                      +003760.00
 CP039  +2013257.500  CE 800 Jan 01 - HM Nautical Almanac, UK 2020                      +002940.00
 CP040  +2049782.500  CE 900 Jan 01 - HM Nautical Almanac, UK 2020                      +002230.00
 CP041  +2086307.500  CE 1000 Jan 01 - Morrison, Zawilski, Honenkerk, Stephenson 2020   +001650.00
 CP042  +2135099.500  TSE Kerkrade TT 1133 Aug 2 CE - Stephenson 2020                   +000960.00
 CP043  +2154855.500  TSE Halych TT 1187 Sep 4 CE - Stephenson 2020                     +000950.00
 CP044  +2173755.500  TSE Cerrato/Toledo TT 1239 June 3 CE - Stephenson 2020            +000825.00
 CP045  +2199565.500  ASE Paris TT 1310 Jan 31 CE - Stephenson 2020                     +000725.00
 CP046  +2207036.500  TSE Zbraslav TT 1330 Jul 16 CE - Stephenson 2020                  +000685.00
 CP047  +2224872.500  TSE Sevilla TT 1379 May 16 CE - Stephenson 2020                   +000565.00
 CP048  +2234765.500  TSE Bordeaux/Liege TT 1406 June 16 CE - Stephenson 2020           +000500.00
 CP049  +2244628.500  TSE Karlstejn TT 1433 Jun 17 CE - Stephenson 2020                 +000420.00
 CP050  +2261106.500  TSE Salamanca TT 1478 Jul 29 CE - Stephenson 2020                 +000310.00
 CP051  +2269936.500  ASE Krakow TT 1502 Oct 1 CE - Stephenson 2020                     +000260.00
 CP052  +2283284.500  TSE Sevilla TT 1539 Apr 18 CE - Stephenson 2020                   +000200.00
 CP053  +2304782.500  TSE St. Andrews (Scotland) TT 1598 Mar 7 CE - Stephenson 2020     +000120.00
 CP054  +2312752.500  CE 1620 Jan 01 - Fit with beginning of tabulated values.          +000124.00

 - For Years before CP001 DeltaT is computed as [ -20 + 31.987 * ((y - 1820) / 100)**2 ]
 - For Years from 1620 to 2021 see Astronomical Almanac (pages K8-K9) and IERS Bulletin A from https://datacenter.iers.org/eop.php
 - For Years from 2022 to 2029 predicted values are used. See https://cddis.nasa.gov/archive/products/iers/deltat.preds 
 - For Years from 2030 onwards DeltaT is computed as [ -65.6 + 32 * ((y - 1820) / 100)**2 ]

 Sources:
 (1) - The dating of seven classical greek eclipses – Stephenson, Morrison, Hohenkerk – Journal of Astr. History and Heritage – 47-62 (2020)
 (2) - The acceleration of the Moon and the Universe – The mass of the Graviton – Göran Henriksson – Advances in Astrophysics, Vol2 No. 3, August 2017
 (3) - The Double Eclipse at the Downfall of Old Babylon - Emil Khalisi - 14th July 2020
 (4) - Joshua’s Total Solar Eclipse at Gibeon - Emil Khalisi - February 2021
 (5) - Addendum 2020 to Measurements of the Earth's rotation 720 BC to AD 2015 - Morrison, Stephenson, Honenkerk, Zawilski - Version 1
 (6) - Addendum 2020 to Measurements of the Earth's rotation 720 BC to AD 2015 - Morrison, Stephenson, Honenkerk, Zawilski - Version 2
 (7) - Ptolemy, Babylon and the rotation of the Earth - John Steele - 2005 A&G….46e..11S
 (8) - HM Nautical Almanac Office - http://astro.ukho.gov.uk/nao/lvm/ (Basically Stephenson's et al. recent work)

6. Added a note on the Mutual Events tab explaining why sometimes events could be missing from this list. I computed all this stuff more than twenty years ago. I remember that it tooks a long long time to get these results. 🙂

7. Implemented the third and fourth Dynamic Ephemeris Terminal so they now show:

T1 : Ecliptic Geocentric Coordinates of Planets and Moon at True Equinox of Date.
T2 : Ecliptic Topocentric Coordinates of Planets and Moon at True Equinox of Date.
T3 : Equatorial Geocentric Coordinates of Planets and Moon at True Equinox of Date.
T4 : Equatorial Topocentric Coordinates of Planets and Moon at True Equinox of Date

8. Removed 2 Nutation Models. Now 1980 IAU nutation series included into DE ephemeris and the extremely accurate (but slower) IAU 2000A IERS model can be used.

5 thoughts on “** VERSION 0.9.9.374R CHANGELOG **”

  1. BERCU
    Reply

    Hi
    Nice improvements ahead !
    Steven C. Albers, who published “Mutual Occultations of Planets: 1557 to 2230” (S&T: March 1979, page 220), has computed in 2020 the geocentric conjunctions of 2 planets for closest approach from 18705BC to AD10860
    (http://stevealbers.net/albers/ast/conjun/conjun.html). It is an interesting source for making comparisons.
    A few months ago you explained to me why the occultation of Mercury by Venus observed by John Bevis at Greenwich Observatory on May 28, 1737 is not listed in “Mutual phenomena among Planets”. However Uruk1 shows this mutual occultation at 21:46 UT. Do you think useful to add a note recalling this occultation. Some users might be surprised not to find this famous occultation.
    Buona fortuna per tutto questo meraviglioso lavoro.
    Regards

  2. developer
    Reply

    Hi,
    of course you are right. Parallax involving Mercury and Venus is not negligible with respect to their apparent diameter and since I computed (many years ago and by means of the good old VSOP87) geocentric data for these events this problem could be present in other cases. John Bevis’ observation is pretty famous so in this case its lack is particularly noticeable. I’ll place a note about that.
    However I took the opportunity to do a check with the DE440. I temporarily disabled the topocentric calculation in Uruk1 and found as least geocentric distance between Mercury and Venus:

    1737 May 28 at 21:50.85 UTC 36.20″

    This value is actually greater than the sum of apparent radius of Venus and Mercury, 29.2″, so it’s confirmed that there’s no geocentric occultation.

    S.C. Albers reports:

    1737 May 28 at 21:50.36 UTC 36.49″ (which ephemeris? I didn’t check it out)

    Think I’ll follow your hint. 🙂

    à la prochaine

    Alberto

  5. Kamil
    Reply

    “1C. BUG : when Windows 10 is configured (Screen Menu) to show everything magnified of 125% some controls are not shown correctly. This problem should be disappeared.”

    And if not, right click on the Uruk_One icon, select “Properties”,
    then click the “Compatibility” tab, and at the bottom click “Change settings for high DPI”,
    at the bottom check the box “Bypass high…” and select “System” and then “OK” twice.
    For me, this solved the problem.

    Regards

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