NavList:

Attached is part of the sunrise/sunset azimuth table that is included in my Lat & Long booklet (2nd edition). It uses Hc = -36.6', which is the refraction correction for the sun's center, plus an eight-foot eye correction.

You can see that it gives the same result as George's example, Zn = 298d for sunset, and 62d for sunrise, for a dec of N22 and Lat N34.

As George shows, these results are quite insensitive to height-of-eye and upper or lower limb, except at polar latitudes. (On the summer solstice at N65d lat, the difference in the upper and lower limb Zn is 4.4d.) And for 100 foot height-of-eye, the correction is only -9.7', which is much less than the semidiameter. So it doesn't change Zn significantly (at least for the accuracy requirements in small boats).

You can easily read these Z azimuth angles off of H.O. 249 because these tables include negative altitudes.

BTW, I don't understand the value of introducing the "amplitude" concept -- it seems completely unnecessary. What's wrong with Zn??

JK
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------