NavList:

Frank,

Maybe I am just nit-picking, but here is what jumped out at me:

-The diagram arrows shows RA as being measured from east to west, like lat-lon west of the prime meridian. Isn't RA always measured west to east from the first point of Aries all the way around and back to the start? Thus for ex, Aries being 0h RA and then counting up eastwards until, say, Markab which as I recall is at 23h RA??

-in the second para, it states: “Just like lines of longitude, RA lines are also great circles converging on the north and south celestial poles.”  Unless I am mistaken, the the equatorial circle is the only circle of latitude that qualifies as a "great circle"(orthodrome) because by definition, to be a great circle, it must cut through the earth's center point. All the other circles would be considered minor/small circles, no?

Now I agree that I am definitely being persnikity in thinking that RA should always be expressed in hours and not degrees. I realize that degrees is also acceptable, but good practice would seem to be to refer to it in hours in order to avoid confusing an RA value with some other coordinate system. (As Frances pounded into my head, "Constant Vigilance!") ;-)

-p