NavList:

Andres Ruiz you wrote: It is interesting to remark that in 5 minutes of time the azimuth of the rising sun increases in nearly 1º.

Andres
Using ‘Navigator’ I get that's 55.8’ across and 40.4’ up, or 68.9’ along the Sun’s trajectory in 5 minutes.  It’s also, 11.2 or 13.5 degrees per hour, which isn’t all that far from the Boy Scout value of 15 degrees per hour.  The different rates of change of Hs and Az are much more noticeable when look through a peri-sextant to try and find longitude by the folded graph paper method for 40 minutes either side of noon.  You hardly have to touch the Hs setting, but you find yourself moving the sextant sideways in its mounting fast enough to notice.  In fact, I find it easier to judge the position of the next observation and wait for the Sun to drift into the centre of the graticule.   Then note the time.  DaveP