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All:

Some further notes....

Kevin is correct, "It all depends on what you want to do" - ie., how deep you want to search ---- what you want to set your mag limit to, what's the smallest mag drop you feel you can discern, what's the smallest asteroid size to use in a search.... etc.

Some have mentioned that they get an error after their 1st 100 or 300 asteroids. I find this puzzling. Essentially, with Occult4, it should either be finding events or not (working or not working). I can only think of 2 things that might cause this...
1) There's was an initial error in formatting in one of the 3 downloaded asteroid databases. I've seen this happen a few times. Solution - reload the 3 databases. You may need to wait until the next update to a database for the issue to clear.
2) You are overloading the output in your Search.

First, there is a default limit in Occult for the number of events it can find in a single Search. The default is 20,000. This number can be found by going to the Main Menu --> Maintenance, then go down to "#11". I have mine set at 40,000. But as stated in the program, "If the number is too large, the program may run out of memory". 40,000 seems fine for both my Win10 computer (4Gb memory), and Win11 computer (32Gb memory).

You can overload the output in a couple ways.......
a) You are searching too deep. You may need to relax your mag limit, mag drop, and asteroid diameter.....

FYI: The number of events you see listed in the output (in List & Display) is most likely [much] smaller than the number of events the program actually [initially] finds. When you press "Search" the program builds up a list of events it finds ("behind the scenes"), then at the end of the Search it takes into account the "Filter settings" in "List & Display" and displays only the events that pass those filter parameters. There is a way, during the initial Search, to limit the number of events that Occult4 finds "behind the scenes" -- which helps to avoid an "overload" of events. This can be done via a setting on the "Search Page", and is in the aqua-colored box below the star catalog. This involves setting a number in the "Passes within" box (see the image I attached in a previous post). There I have mine set for "Passes within 900 km" (of the Lat & Long of my observing site). If this box is unchecked, Occult4 may actually build a database (behind the scenes) for all events it finds that fall somewhere OVER THE ENTIRE EARTH! I think you can see this has the possibility of creating a VERY large "behind the scenes" list of events - and can result in an overload error. So I would suggest that users check this box, put a value in it (maybe 500km), and make sure your approx Lat & Long are correctly displayed.
Also in this aqua-colored box, set a realistic mag drop, and star catalog mag limit. This will also prevent any overloads. [I've found mag drops of less than ~0.15 mag give me more headaches than it's worth - wondering if the "drop" I see is real or just noise].
Make sure all 3 boxes are checked.

Another way to have a Search hault due to an overload......
b) You are doing a search for too long a period of time.
I have seen overloads happen (rather easily) this way. I know folks might like to search for a month or so at a time. I feel this is NOT WISE unless your search parameters stop at something like mag 11, you are using GAIA 14, and any asteroid is larger than perhaps 20km.

After much trial and error, I would really -suggest- you do the following:
Do your (normal) searches for one day (well, actually, night) at a time (!!!!)
I find doing searches for just 1 'day' convenient. I just keep track of the weather forecast a few days ahead, and if I see the potential for a clear night coming up, I go over to the computer, enter in a Start and End date of the same day (number). I then start the search and walk away from the computer and come back later - when I see a list of events displayed. If it's clear out, it's then very handy to just consult that nightly file. After that night has passed, simply delete the file.
....Or you can do a nightly search just prior to an evening's observing.

"My paths don't match what I see on OW"...........
Again...,? remember the initial output from Occult4 will be based on the MPC's MPCorb database(!), and will NOT be based on JPL/Horizons. There is a further step you must do to get JPL-based predictions. Maybe I'll write that step up later, but it's better to cover in a Zoom session.

That said... There IS a way to get a JPL/Horizons prediction (path) directly --- [usually] FOR A SINGLE ASTEROID.
Do the following:
* At the Search Page, in the beige box, you will see a box saying "Select asteroid or Set a comet".
* Click on the box
* At the prompt, enter the asteroid number without parenthesis (or enter a provisional designation)
* Click OK
* Press Search
IF OW(C) predicts an event involving this [single] asteroid (for the selected night), the event should show in List & Display, and if you click on the row of text the path map that is drawn should [very closely] match that shown on OW(C) --- providing the path on OW(C) is based on JPL/Horizons.
So this is a way you can "test" the accuracy of paths output from Occult4.

FYI: When I get a JPL-based path via Occult4, it almost always matches the path in OW(C) - VERY closely (prividing the path in OW(C) is also JPL-based.

When you get an output (list of events) in the "List & Display" window, be advised that you can refine the events which are displayed by modifying the "Selection filters" at the top. We can cover that in another post or better yet, in a Zoom session.

Lastly..... If you run into an error stating that Occult4 can't "resolve" the JPL site... check your Internet connection.

Clear Skies (very wishful thinking for me lately),

George