Make a spirit visible ?

Hello i was reading Guardian of the forest page 132

This item is use ton make visible 3 ghostly gladiators with magic might : 20. But the trumpet has no penetration. It is an error or the spell Vision of the Haunting Spirits, MuMeIm 40
don't need to penetrate to make ghost visible ?
Thanks for your responses.

it appears, that sounding the trumpet is just a cue for the gladiator spirits to coalesce and arm up: so Penetration is not an issue there.
But otherwise its lack of Penetration makes that trumpet indeed rather useless.


Thanks, but the spells itself if cast by a magus need to penetrate ?

I should think so. By ArM5 p.150 box Muto Mentem Guidelines it changes spirits (MuMe) by attaching visibility (Im) to them.


It think this too. Thanks for all.

Visions of the haunting spirit does indeed require penetration.
I believe the trumpet to be flawed. It should have been designed with penetration.
In my I have increased the daily number of uses and given it a penetration of 26.
This seriously increases the trumpets usefulness.

I thank this too. Probably a error of the writer.
I will add penetration.
Thanks for all