>> If you want to include only naked-eye celestial objects it's easy
>> enough.
>>
>> But if you also want to include faint NEO's, this calculation would
>> include a search through a fairly large database of known NEO's,
>> making sure you use up-to-date orbital elements, or performing a
>> numerical integration to update these elements.
>
> Hello Paul,
>
> I am interested in non-artificial objects, mainly asteroids and
> comets for such a list. As Guide already knows how to calculate their
> positions i would not expect the feature to be that difficult to
> implement.
>
> Depending on the "home" position used for the search, a reasonable
> selection of all the orbital elements could be made to avoid
> computing all the orbits, using the major axis and excentricity of
> the orbit.

Such a list would still include at least hundreds of objects, probably
more than a thousand. Of course that's far less than all known asteroids
which now are more than a hundred thousand.

> I just thought this would be a nice feature, imagining some
> presentation to customers at our public observatory:
>
> "we are looking at mars now, which is nearing opposition, when it will
> be only X million kilometers away from earth. Interestingly, there are
> actually Y named asteroids which are nearer then mars today, according
> to this list created with the GUIDE8 software.

If you require these known NEO asteroids to be named, the list will
be quite short. Few of them are named, and most of them aren't even
numbered. But we still know about them.

> The brightest of these is ..., which we have imaged yesterday, see the
> trail on the image..."
>
> Regards, Martin