7 shows clearly that heights of the MON and NOO are practically identical. The geocentric velocity and entry geometry is almost the same for both meteor showers; therefore, the beginning and terminal height would mostly depend on the physical properties of meteoroids, such as the mass, the bulk density and internal structure. The heights are given in Table 3 and the heights as a function of photometric mass in Figure 7. In Table, 3 we also compare the heights of MON and NOO with the high quality Geminids orbits from the SonotaCo database. Geminids from the SonotaCo database have beginning and terminal heights 5km lower than other video observations made by similar techniques (@koten04). MON and NOO meteors have beginning heights 6–7km higher than Geminids, which could indicate that meteors from C/1917 F1 Mellish have lower bulk densities and are more fragile. On the other, hand Geminids with similar geocentric velocities belong to the densest and most rigid meteors observed (@ren04).

   shower   beginning height\[km\]   terminal height\[km\]
  -------- ------------------------ -----------------------
    MON         $102.6\pm2.7$            $86.1\pm4.8$
    NOO         $101.5\pm3.9$            $85.1\pm5.3$
    GEM          $95.6\pm3.3$            $80.2\pm7.0$

  : The beginning and terminal heights of the December Monocerotids and November Orionids in comparison with the Geminids using the high quality 