If you find that Photo Ephemeris Web always opens at the 'wrong' location, e.g. the default location (Timbuktu) or a place you visited in the app months ago, chances are you have saved a bookmark for the app that includes a specific location (and probably date and time also).
To have the web app open at the location you last visited, you should save the bookmark as https://app.photoephemeris.com, ensuring that there are no additional parameters saved in the link (e.g., https://app.photoephemeris.com/start?center=37.269340%2C-112.947950&ch=1.524&cw=100&dt=2023-10-22T23%3A29%3A31.240Z&ll=37.269315%2C-112.947990&sh=1.5239999512320015&sw=100&z=14).
Previous versions of Photo Ephemeris Web appended various parameters such as the pin location, map center and date and time by default, requiring you to edit the bookmark. If you saved a bookmark from a previous version you may need to edit the bookmark. At present, those parameters are included on the links available from the Share form. If you copy the link from the Share form and save that as a bookmark you will still end up in the same place every time you opened that link.
Here's how to do that using Safari - if you're using a different browser, the exact steps for adding and editing a bookmark may be different, but the principle is the same.
Save a bookmark
Previously, when you saved a bookmark for Photo Ephemeris Web as shown below, the bookmark was for the specific location, date and time that you were viewing when you created it:
On editing the bookmark, you can see the additional parameters that must be removed in order to have the app open at the most recently used location and the current date/time;
Edit the bookmark as shown to delete the extra parameters:
You should be left with a clean bookmark as shown:
When you access this bookmark, the app will open at the last visited location and at the current time and date.