Pete,
I've been observing the asteroids for 30 plus years and like you have wanted a way to 'filter' out what I had previously seen. I had the same problem with the large MPCORB.dat file. I have been using a shareware text editor that will handle almost any size file. http://www.textpad.com/ Another big advantage of this program is that you can sort the enormous file by multiple columns. It has been a real time saver for me when editing large files.

Another way I've been able to catalog what I've seen is to put this info into a database. I still use and old DOS program called Alpha Four, though there is a newer Alpha Five for Windows. Using the database allows me to build a listing of opposition data for each year and them filter out those that have been previously seen. This won't keep Guide from displaying only your 'selected' asteroids but it is an easy way to keep up with oppositions and favorable elongations, etc.

Hope this might help.
Ben Hudgens
Stephenville, TX



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