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It appears that that swetest can tell the exact longitude as long as you give it the date and time

./swetest -pt -b17.11.2023 -ut22:43
date (dmy) 17.11.2023 greg.   22:43:00 UT        version 2.10.03
UT:  2460266.446527778     delta t: 69.109781 sec
TT:  2460266.447327659
Epsilon (t/m)     23°26'18.3245   23°26'10.2223
Nutation          -0° 0' 7.8330    0° 0' 8.1021
true Node         24°29'59.7465    0° 0' 0.0000    0.002502442   -0° 3'35.2933

Now my question is can one get the time and date for the nodes if it gives the longitude lets say 24.5 same as the one in the swetest example .. can we calculate using swisseph, kind a like how solcross does or mooncross ? I only need a little hint on how to do it .. thank u <3

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    $\begingroup$ The ``` has to go on a line by itself. $\endgroup$
    – Mike G
    Oct 2, 2023 at 2:17

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I don't think swisseph has that capability, but skyfield.searchlib.find_discrete() is made for this sort of thing. You would need to pass it a function which returns an integer indicating whether the node longitude at a given time is east or west of the value you're searching for. The documentation and an answer here have relevant examples.

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  • $\begingroup$ thank you Mike, i really appreciate it <3 $\endgroup$
    – dimitri33
    Oct 3, 2023 at 19:50
  • $\begingroup$ hey Mike G, can you give me another hint with this please ... i can't even sleep as i keep going over this thing :( pastebin.com/NBUMFrtH $\endgroup$
    – dimitri33
    Oct 5, 2023 at 22:38
  • $\begingroup$ 1. observe from Earth instead of the Sun; 2. let function return ((observed_longitude - longitude) // 180).astype(int) % 2; 3. step_days = ~1/4 of the expected period; 4. filter longitude_times by in_state == 0 $\endgroup$
    – Mike G
    Oct 6, 2023 at 4:00
  • $\begingroup$ pastebin.com/dcUDALrB $\endgroup$
    – dimitri33
    Oct 6, 2023 at 4:24
  • $\begingroup$ That code looks at the longitude of the Moon itself and should find 12 or 13 crossings per year. Now try looking at its orbital elements. $\endgroup$
    – Mike G
    Oct 6, 2023 at 4:35

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