Mike Shaw asked: > <Snip> > For latitude +32 (isn't that your approximate latitude, John?), a > horizontal dial's mean absolute error would be 6.8 minutes. > <Snip> > > But don't you also have to adjust that figure for the longitude correction ?
The 6.8-minute figure assumes a perfectly constructed, perfectly aligned horizontal dial for latitude +32 that implements the longitude offset in the hour lines' layout. So, yes, if the dial lacks this longitude correction, then the mean absolute error will increase by 4 minutes for each degree of longitude difference from the standard meridian. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Mark Gingrich [EMAIL PROTECTED] San Leandro, California
