Welcome to Subsim, jrazz

XS
My guess is that you have got radar contacts with the ships only, these will also show-up on the map, so they are not yet in visual range. You can check this in the crew messages, and in the 'Bridge' section you can ask for the bearing and range of the nearest contact. If you get 'no visual contact' as a response then nothing is in sight yet. You should get visual range at about 6 nm or less.
However I cannot judge this exactly because I don't play the stock game but a modded game where the symbols and contacts are different.
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