We present CCD broad band photometric observations obtained in the field of the
Third Galactic Quadrant open clusters NGC 2580 and NGC 2588 (BV(I)_C and
UBV(RI)_C respectively). From the analysis of our data we obtained that
NGC 2580 is at a distance of about 4 Kpc and its age is near to 160 Myr.
Whereas NGC 2588 is placed at about 5 Kpc from the Sun and has an age near of
450 Myr. NGC 2580 belong to the Vela-Puppis spur arm whereas NGC 2588 is nearer
to the local arm structure. For both clusters, we also built the corresponding
luminosity functions (LFs) down to V ~ 20 and their initial mass functions
(IMFs) for masses above M ~ 1-1.5 M_sun. A determination of the IMFslopes for
the most massive bins were computed and we found the values of
x ~ 1.3 for NGC 2580 and x ~ 2 for NGC 2588. This last cluster
appeared to be much more extended than previous estimations with a core-corona
structure produced probably by dynamical effect.