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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Drum Sextants
From: Mike Burkes
Date: 2005 Jun 15, 12:48 -0700
From: Mike Burkes
Date: 2005 Jun 15, 12:48 -0700
Tenths have their places in Lunars and if observer requires surveyor
accuracy all on land of course.
Quick correction on my C.Plath description:You can resolve the measurement to the nearest tenth when two vernier lines on the fixed portion are bracketed by two vernier lines on the rotating drum.I got it arse-backwards in my first comment.I can't offer a learned opinion, except to say that in my experience, being able to resolve angles to a tenth of a minute of arc seems to be overkill and perhaps expecting too much of the human eye and brain. I own a C.Plath which takes it to two tenths, but if I really want to, I can resolve it to 1/10th when the two venier lines on the rotating drum are bracketted between two lines on the fixed portion. Sometimes I fool myself and use thiIf I am not mistaken in my recollection, I do believe that Cassens and Plath sextants are graduated in tenths of a minute.Ok. I have my flak jacket donned. Let 'er rip.....Robert----- Original Message -----From: Mike BurkesSent: Wednesday, June 15, 2005 1:18 PMSubject: Drum SextantsHI folks, In continuing this thread I posed this question a while back regarding the division of the micrometer minute scale into tenths.I have always wondered why super quality sextants like some Plaths and others do not have their minute scales further divided into tenths.I would appreciate any feedback regarding that and thanks much!Mike Burkes