NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navy MK 5 Octant Using Natural Horizon
From: Alexandre Eremenko
Date: 2012 May 2, 17:21 -0400
From: Alexandre Eremenko
Date: 2012 May 2, 17:21 -0400
Greg, Thanks. As I understand, the only advantage of Polaris, in comparion with some other star will be that the hour angle does not change much, so you do not really need to time accurately and even reduce your observation. The same can be achieved with the Sun, but you need to time and reduce accurately. Alex. On Wed, 2 May 2012, Greg Rudzinski wrote: > > The best way to figure index error for a bubble octant is to use Gary LaPook's Polaris method (see archive). Observe Polaris at zero LHA or 180 LHA. You can also take 30 observations in a row then average and apply an I.C. that gives a 0.0' intercept that compensates for the average intercept. > > The natural horizon prism and bubble horizon are separate and require separate trials for determining I.C. > > Greg Rudzinski > > [NavList] Re: Navy MK 5 Octant Using Natural Horizon > From: Alexandre Eremenko > Date: 2 May 2012 14:59 > Look like very good resuts (for a bubble) to me. > The sky just cleared in Indiana, let me try some bubble observations > with my MkIX A. > I conclude from your messages that your IC is different for the horizon > and for the bubble. > > I never measured my octant bubble IC. How do you do this? > Neither I measured it with a horizon, because a horizon is something > I see very rarely in my life:-( > > On the other hand I never detected any systematic error. > > > Alex. > > ---------------------------------------------------------------- > 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 > ---------------------------------------------------------------- > > > > > : http://fer3.com/arc/m2.aspx?i=119348 > > >