Locked Re: Moon Dx #general

Charles Suckling

Hi Mike

Yes, I think its the difference between geocentric and topocentric
calculations. If you look at Moonsked, the 'Range' changes continuously in
one direction (today centre of moon is moving closer to centre of earth).
Watch' Dist' in WSJT-X and you should see it increase again after transit,
as the observer moves away from the moon.

For comparison, I suggest using JPL Horizons to provide definitive data for
comparison. At the present time, JPL and WSJT-X differ at my location by
about 5-6km.


Charlie DL3WDG

On Mon, 26 Sept 2022 at 10:57, Michael Black via groups.io <mdblack98=
yahoo.com@groups.io> wrote:

I had an older version of PSTRotator and they agree much better now with
17.28 -- differing by around 100km as of right now so only 0.026% between

WSJTX 390620
PSTRotator 390506
MoonCalc 386676

MoonCalc is now the odd one out and off by approx 3900km but I imagine
they are doing the orbital distance and not surface-to-surface.

Mike W9MDB

On Sunday, September 25, 2022 at 06:51:13 PM CDT, Svend, OZ7UV <
spanget@...> wrote:

Hi Mike.

I just got this answer:

PstRotator v17.28.
The displayed Moon distance is now the distance between your location and
the Moon surface.
It is still a difference around 100km between PstRotator and WSJT-X, and I
will try to find the reason.

Codrut - YO3DMU
\Svend, OZ7UV

man. 26. sep. 2022 01.02 skrev Michael Black via groups.io <mdblack98=

Trying to determine accuracy of moon distance.

Using WSJTX Astronomy window, PSTRotator and https://www.mooncalc.org

All 3 seem to agree pretty well on Az and El but distance is off by about
5000km comparing WSJTX to the others.

As of 13:00 or so I see
WSJTX 383,115
PSTRotator 388074
MoonCalc 388199

The equatorial radius of the moon is 1,738km so that doesn't explain the
difference (of about 1.3%).

It seems the code in wsjtx was done with certain deliberation so I'm
hoping WSJTX is more accurate. But how to resolve who's right?

Mike W9MDB

Join {main@WSJTX.groups.io to automatically receive all group messages.