NavList:

From the Observer's Position (here Scotland Neck, NC) and given the geometry involved - with the apparent ISS track intercepting Vega apparent vertical zenith at an angle close to 46° - interesting to see that if you proceed 6 NM towards Vega, it will "raise" Vega by 6' over the new local horizon, and the apparent ISS track will become "closer" from Vega by 1°.

In other words, if one can estimate such apparent Minimum distance of the "ISS track" from the picture (BTW beautiful Virginia Tulip Tree /  Liriodendron Tulipifera, no ?) to +/- 0.1° which seems realistic - I have made it at 4.8° - the uncertainty on ground of the "ISS Lop" should remain under 1 NM.

Since the Vega Lop is accurate to also better than +/- 1 NM, this explains why the geometry of the problem significantly narrows down the end result uncertainty which, even with the current GDOP, should remain under 2 NM.

And as regards your post immediately here-under, YES, please be so kind as to publish your own comments.

Thanks again,

Kermit

Re: Position fix by visual satellite pass
From: Frank Reed
Date: 2023 Aug 1, 10:48 -0700