NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sun Shots Through Clouds
From: Lu Abel
Date: 2014 Nov 2, 16:58 +0000
From: Lu Abel
Date: 2014 Nov 2, 16:58 +0000
What is the iPhone app, Greg?
I have seen navigation apps (not necessarily celestial) that range from really good to junk. Would love to hear of apps that people think are really good ones.
An example: One of the centerpieces of traditional coastal navigation is taking bearings. But anyone who has tried this from a recreational boat (vs a cruise ship) knows that boats bounce around a lot and it's very hard to get an accurate bearing. I found an app "Theodolite" that imposes compass direction and even tilt onto a camera image. So I can snap a shot of a distant object and get its bearing. With a name like "Theodolite" it isn't touted as a navigation app, but it seems excellent at something that challenges us all.
From: Greg Rudzinski <NoReply_Rudzinski@fer3.com>
To: luabel@ymail.com
Sent: Saturday, November 1, 2014 6:56 PM
Subject: [NavList] Re: Sun Shots Through Clouds
Sam,No need to be perfect with the preset. Time can be 10 minutes off and still get the Sun into the field of view. I use a phone app to calculate the Hc for my assumed position. The app has an almanac and a chronometer so by pushing the now button an Hc pops up which I double to set the artificial horizon sextant preset. If using 229 / 249 the the nearest degree of latitude, LHA, and declination should get the Sun into the field of view.Greg RudzinskiFrom: Samuel L
Date: 2014 Nov 1, 12:18 -0700Greg,Preset Altitude is something we've just begun to experiment with. So far, using an AH, we can see both images of the Sun but not exactly superimposed or Upper Limb or Lower limb touching.Tell me if this is right or wrong....or the correct way to go about it.- determine the exact time you want to take the Sun sight and calculate Hc- preset the Sextant to the calculated Hc (when using an AH multiply Hc times 2 and subtract or add SD depending upon which limb is being observed).What do you think? What method do you use?Thanks,Sam L.
