target cross should scale down with size parameter

[d33psky]

When using -size 1 (or smaller) the target cross becomes really large.

Example image of fchart3 -usno-nomad ~/fchart3/USNO-NOMAD-1e8.dat -limstar 20 -limdso 25 -size 1 --force-messier --force-asterisms --force-unknown --output-file ACO2065.pdf Abell2065

At a size of -size 0.5 the cross edges are even outside the viewpoint.

[skybber]

The mark is proportional to the size of object. Fchart uses cross marks for galaxy clusters (unclassified objects), so the size is getting bigger in smaller fields. The shape of mark is little bit misleading, since it does not mean the centre of field but type of object.

[d33psky]

I can appreciate that. But for this graph :

I did not recognize the diagonal lines as part of the object mark, hence this ticket.

[skybber]

Looks strange - you're right may be it could be replaced by better mark and if the size of object is more then 50% of img it will be hidden.