NavList:

Yesterday's sunset emerged from a low ceiling at the very last minute to be photographed and timed on the horizon. There is something neat about using the horizon as a natural sextant. The sight reduction is not so neat since the calculated altitude and observed altitude are both negative. I am not much for the negative so at least the calculated altitude can be made positive by selecting an assumed position further west.

Actual position
Lat 34* 10.4' N
Lon 119* 14.1' W

Height of Eye 12 ft.

hs 0* lower limb Sun
dip -3.4'
ref. S.D. -17.8'
Ho -21.2' (Nautical Almanac)

UT 02:55:07 8/1/2012
GHA 222* 12.9'
LHA 102* 58.8'
Dec 17* 40.6'
Hc - 22.3'

Intercept 1.1 toward
azimuth 291.8*

If an assumed longitude of 120* 12.9' W is used in lieu of 119* 14.1' W then :

LHA 102*
Dec 17* 40.6'
Lat 34*
Hc 19.2'

Intercept 40.4' away
azimuth 291.3*

For some having a positive calculated altitude might avoid some confusion on the sunset intercept determination.

Greg Rudzinski

----------------------------------------------------------------
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
----------------------------------------------------------------