NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sun Shots Through Clouds
From: Gary LaPook
Date: 2014 Nov 5, 21:07 -0800
From: Bruce J. Pennino <NoReply_Pennino@fer3.com>
To: garylapook@pacbell.net
Sent: Wednesday, November 5, 2014 7:26 PM
Subject: [NavList] Re: Sun Shots Through Clouds
Bruce
Attached File:
(IMG_9767.JPG: Open and save)
From: Gary LaPook
Date: 2014 Nov 5, 21:07 -0800
If you are superimposing the sun's images do NOT use the sun correction tables in the N.A. because they incorporate the semi-diameter correction, use the star correction table.
gl
From: Bruce J. Pennino <NoReply_Pennino@fer3.com>
To: garylapook@pacbell.net
Sent: Wednesday, November 5, 2014 7:26 PM
Subject: [NavList] Re: Sun Shots Through Clouds
I have not been following this topic too carefully, but something seems
incorrect here. When not superimposing the image, I just checked in Sextant
Handbook/Bauer, with an AH, the sun LL is brought down to the upper limb, as
done normally (double reflection is erect). Divide by two and use normal
refraction corrections.
It seems to me if images are superimposed via AH, because the sun
correction tables are set up for LL, there is a semi diameter correction.
With superposition, the half-angle is too large(for using the standard
tables) , so subtract 16 minutes (I think) from the tabulated refraction
correction. Did I say/write this correctly?
Bruce
From: Samuel L
Sent: Wednesday, November 05, 2014 4:51 PM
Subject: [NavList] Re: Sun Shots Through Clouds
Below is a photo taken today at GMT 14:59:31 in an effort to try out
Worsley's method using an AH. The Sun had no discernible shape except as seen in
the photo.
Hs- 55d 11.0min
The Sun was superimposed on the AH and an amber colored filter was used to
help distinguish between the two images.
No corrections were applied to the Hs Sun sight except to divide the Hs by
two to get 27d 35min. In other words- the sight was very sloppy except to make
as certain as possible that the Sun images were superimposed.
Results-
Ap Longitude- W075d 58min
Ap Latitude- N041
Z= 150d
Intercept= 24nm.
The resulting LOP, as happened yesterday, passed directly through my GPS
determined location.
Sam L.
Attached File:
(IMG_9767.JPG: Open and save)
