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** VERSION 0.9.9.473R CHANGELOG **

1) BUG : Jupiter satellites shadows sometimes were not shown at the correct distance. SOLVED.
2) All the definitions “True Equinox of Date” have been changed to “Apparent”
3) Tycho star names appear with a Zoom factor greater than 100, Hipparcos names with a value greater than 50.
4) When switching to different stellar catalogues the update takes place immediately without the need to upload archives.
5) In Terminal T6 now the limits of the totality/annularity path are completely defined. Code is under test.
6) Longitude and Latitude in the Main Window are handled as decimal values.

Current Main Window

7) Found a public domain data source to make an offline world map at:

Natural Earth data in GeoJSON
Public Domain Maps
https://github.com/martynafford/natural-earth-geojson

I transformed all this stuff in several files containing arrays of constants compatible with Pascal, and the job is almost done. This representation of the Earth’s continents is linked with the internal archive of locations and will be used for showing totality/annularity paths of the Solar Eclipse managed by Uruk_One. Partial eclipses are ignored at the moment.

8) The default locations file has been heavily reworked, hopefully correcting all the mistakes contained inside.

Earth Map almost completed.

9) Two new sections added to Preferences Window. The first one contains some flags used by the new EARTH MAP View, the second one allows to load a reduced dataset for the Solar Eclipses and Lunar Eclipses Canons, from 3000 BCE to 3000 CE. In this way one can have a faster navigation through historical and contemporary eclipses.

The new Preferences Window

10) Starting tests on Eclipses Path. Fingers crossed…….

1601 Xmas Day. An annular eclipse covered almost all G.B.

11) All the definitions of Universal Time contained into Uruk_One have been changed from UTC to UT1. UT1 is the successor of the old GMT, and it is more correct in the astronomical sense to indicate UT. UTC is based on the International Atomic Time and is occasionally adjusted to UT1 through the addition of a leap second.

12) When Longitudine or Latitude is manually changed, the current location turns into “Manual Entry” and the Timezone is intentionally set to 0.

13) Left Click + Button Pressed it is no longer used to move the content of a graphical map. Now a map can be scrolled by moving the mouse over the equatorial or horizontal controls and using the mouse wheel. Four movement steps can be set, 15 °, 1 °, 1 ‘, 1 “. Clicking the left mouse button (without holding the button down) will center the map on that point.

Place mouse over controls and use the mouse wheel to scroll the map.

I’m going to publish version 0.9.9.473R of Uruk_One. Actually the code written so far in order to show Totality or Annularity Path of Solar Eclipses must be considered as a work in progress phase. A representation of a central total or annular SE (marked as *TOTAL*, ANNULAR or HYBRID) can be obtained on the new EARTH VIEW selecting the event from the Solar Eclipses Canon (Show Menu), any other type of eclipse (partial, NOC T/A) willl be ignored. Eclipses occurring at high values of Latitude (typically with a value of Gamma greater than 0.92) usually don’t give a complete definition of northern or southern limits so I chose to show only the central line in this case. This happens with the algorithms I’m currently using, of course, so I am still verifying that I’m correctly doing all the needed calculations. I’m pretty sure that this part of code still contains some bug inside so my recommendation is to use this data with care.

22 thoughts on “** VERSION 0.9.9.473R CHANGELOG **”

  1. Hello
    I am trying to promote Uruk_One within my astronomy association but many people are not very aware of the progress made in ephemeris calculations and continue to use outdated software which is the source of errors for research in the distant past.
    For your information a new version of HORIZONS JPL is on line this morning.
    Check https://ssd.jpl.nasa.gov/horizons/news.html for the updates and for the manual https://ssd.jpl.nasa.gov/horizons/manual.html
    However time spans are still the same https://ssd.jpl.nasa.gov/horizons/time_spans.html

    1. Frankly I give up on understanding what Horizons time span is based on when using DE441.
      I completely agree with your considerations regarding the research.

    1. The native output of the DE441 are barycentric coordinates from 13000BCE to 17000 CE. What I do (and what they could do too) is turn them into heliocentric and then geocentric. This is because usually the barycentric coordinates are not very useful in common practice.

  2. Hi
    The 1601 Xmas annular eclipse map is the same as computed on http://www.eclipsewise.com/solar/SEprime/1601-1700/SE1601Dec24Aprime.html (ephemerides JPL DE406) :
    http://www.eclipsewise.com/solar/SEgmapx/1601-1700/SE1601Dec24Agmapx.html
    G.E. eclipse 12:48:30.64 (URUK_ONE), 12:48:34 (eclipsewise)
    Delta T 120.7s (URUK_ONE), 116s (ecli psewise)
    G.E. Longit. & Latit. -21.51°, 46.57° (URUK_ONE), -22°, 46.57° (eclipsewise)
    Path Width & Central Duration 1057.7 km, 614s (URUK_ONE), 1051 km, 614.26s (eclipsewise)
    Delta T computed by other sources :
    http://ytliu.epizy.com/eclipse/one_solar_eclipse_general.html?ybeg=1601&ind=2&DE=441 = 106s
    https://ssp.imcce.fr/forms/solar-eclipses/1601-12-24 = 86.761s (large gap ?)
    Horizons JPL = 107s
    http://astro.ukho.gov.uk/nao/lvm/ = 108s
    So URUK_ONE computes this eclipse accurately.
    Good idea to reduce the dataset of Solar and Lunar eclipses from -3000 to +3000 because it seems sufficient in most cases.
    Looking forward to testing the new version
    Regards

    1. Hi,
      thanks for the accurate analysis.
      My DeltaT estimation (120.7 sec) is derived from an automatic interpolation between R.F. Stephenson’s value for the 1598 Mar 7 CE solar eclipse (see Source (7) on menu Info -> DeltaT RC Calibration Points) and the first commonly used tabulated value (1620 CE = 124s) published by the Astronomical Ephemeris. Maybe the best estimation available so far? Most likely it is. Indeed the IMCCE value (86.781 sec) sounds so weird….

  3. Hi
    I notice something strange regarding the computation of Delta T by IMCCE :
    For the 1601 Xmas eclipse, UT1 − TT = -86.781 s
    (https://ssp.imcce.fr/forms/solar-eclipses/1601-12-24)
    For 24 December 1601, 12:48:30 UT, Delta T = TT- UTC = 115.7326 s
    (https://ssp.imcce.fr/forms/ephemeris)
    This last value of Delta T matches URUK-ONE and other sources…
    I do not understand either why IMCCE uses the relation UT1 – TT instead of TT – UT…
    I might have missed something…
    Regards

  4. Hi,
    formally what IMCCE declares is right:

    “Les instants des différentes phases sont exprimés en Temps universel coordonné (UTC) à partir de l’année 1962 et en Temps universel (UT1) avant l’année 1962.”

    UTC is a modern time unit based on atomic clocks, continuously synced with UT1 that is based on terrestrial rotation, so the second one is more suitable for astronomical purposes. When talking about of an historical eclipse I myself should write UT1 instead of UTC, and DeltaT should be expressed as (TT – UT1). Anyway the fact is that in 1601 CE the value of (TT – UT1) should be close to 115-120 seconds, not 87 seconds, according to the most recent studies.

    Regards

  5. Buongiorno.
    Segnalo che l’ultima versione del noto software Solex 12.1 (agg. 30/11/2019) del prof. Vitagliano, fornisce per la data in questione, un Delta T = 118 sec.
    Saluti
    L. Torlai

  6. Buongiorno,
    eh sì, a prescindere da quale degli ultimi studi effettuati a riguardo provenga la stima mi sembra che siamo tutti più o meno attestati tra i 116 e i 120 secondi. Lo stesso IMCCE nella sezione Pianeti presenta un DeltaT di circa 116 secondi. Ipotizzo che chi si è occupato delle eclissi sempre sul sito dell’IMCCE sia un gruppo di lavoro diverso, con uso di codice differente per questi calcoli, il che ha generato quella che mi sembra una stima errata, ovvero 87 secondi. Peccato che Solex 12 sia rimasto fermo negli ultimi anni, ma mi pare di capire che i peraltro legittimi interessi naturalistici del Prof. Vitagliano lo terranno lontano da Solex per un bel pò. 🙂

    la saluto
    Alberto Cavalli

  7. Hi
    In April this year I sent Prof. Vitagliano a query on his facebook about the implementation of JPL DE440/441 ephemeris into his SOLEX software. His reply was as follows: That’s not good news for me. Fitting 30 thousand years of ephemerides is a very long and tedious process, lasting usually a few months. But yes, I’m considering it, and for the moment I have opened a new folder in my notebook named DE431.😂 Regards. Aldo.

    Regards

    1. He’s enjoying life in the mountains and with his camera traps. It is right that this is the case. 🙂

  8. HI
    I am going to send an email to IMCCE today to report that there are two values of delta t and ask for an explanation.
    I will give you their answer as soon as possible.
    Regards

  9. Hi
    As quoted in https://journals.sagepub.com/doi/pdf/10.1177/0021828619899188 (Stephenson et al., 2020) a total eclipse of the Sun was recorded in Bede’s Ecclesiastical History on AD 664 May 1. The totality was seen at the monasteries of St. Peter and St. Paul, located near the modern-day Monkwearmouth-Jarrow Abbey on Tyneside (54° 54′ 47″ N, 1° 22′ 30″ W) where Bede lived and worked. It is interesting to compare the values of delta T according to the best sources available :
    Source Max. eclipse UT Sun Alt. delta T
    EclipseWise 17:17:10 19.3° 4111 s
    Xavier Jubier 17:17:15 19.3° 4115 s
    http://ytliu.epizy.com/ 17:18:07 19° 4074 s
    IMCCE 17:19:20 19.2° 3986 s
    Uruk_One 17:18:20 19.2° 4077 s
    Emapwin 17:16:37 19.4° 4141 s
    Not bad for an event observed 1357 years ago…
    Regards

    1. DeltaT is hard to estimate. 🙂
      Anyway, searching for the minimum distance between lunar and solar disk at long -1.375 lati +54.9131 I can find with Uruk_One:

      17:18:09 UT1 DeltaT = 4077 (RC)
      17:17:26 UT1 DeltaT = 4115 (NASA)

      again, IMCCE must have some secret algorithm for computing DeltaT 🙂 🙂 🙂

  10. Hi
    I just received an answer from IMCCE :

    Depending on the models and the analysis of the data, the value of delta T for ancient dates varies over time.

    The form dedicated to eclipses uses the value recommended by Stephenson et al. in a 2016 article (https://royalsocietypublishing.org/doi/10.1098/rspa.2016.0404). The one used in the ephemerides calculation form comes from Espenak and Meeus, Five millennium canon of solar eclipses: -1999 to +3000 (2000 BCE to 3000 CE), NASA / TP-2006-214141, 2006.

    During the next update of our ephemerides computation services, we will adopt the last modelization proposed by Morrison et al. (2021, https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2020.0776), which at 1601-12-24T12: 49: 03 UT1 gives:

    UT1-TT = -106.02 s

    I therefore advise you to use this value for the eclipse, and for the position of the Sun please use the TT timescale and apply this delta T correction on the dates yourself.

    So I suppose the value of delta T computed after their update will be closer to the value 120 s (Uruk-One).

    Regards

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