A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2015 Dec 24, 23:37 -0800
Comparing the standard 2102-D with the CP-300/U I prefer the 2102-D.
The scale is larger which makes a big diference in reading it. The space from the pole to the equator on the star base of the 2102-D is 57mm and on the CP-30/U is only 45mm making the -D 27% larger.
The CP has an extra disk that in marked with longitude 180 degrees in each direction. This allows you to set the star base GHA Aries on the zero mark on the extra disk, turn the index of the disk with the curves to point at the longitude and then it is automatically set to LHA Aries. Nice, but unnecessary. How hard is it to add or subtract your longitude to GHA Aries to find the LHA?
The CP also weighs considerably heavier, the device weights 6.6 ounces while the -D is only 2.5. The entire kit is also much heavier, in the case with the base and the nine disks wieghs 18.9 ounces while the -D is only 11.3 ounces.