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Re: Night Vision Scopes
From: Jos� Otavio O. de Almeida
Date: 2005 Jun 27, 17:10 -0300
From: Jos� Otavio O. de Almeida
Date: 2005 Jun 27, 17:10 -0300
The Zenith Night Vision Scope amplifies light over a broad frequency band, part in the visual, part in the infra-red segments of the spectrum. With some moonlight it does discern the horizon, allowing taking sights, albeit with a precision somewhat reduced due to the unsharp image obtained. ----- Original Message ----- From: "Alexandre Eremenko"To: Sent: Monday, June 27, 2005 2:39 PM Subject: Re: Night Vision Scopes >I have never used a night vision device, > but on a pure theoretical ground I predict > that it will NOT help to see the sea horizon:-) > (And for the stars and the Moon you don't need > any night vision anyway). > Can anyone verify this theoretical prediction? > :-) > Alex. > > P.S. I mean the common modern night vision devices based on infrared > radiation. Another tipe of "night vision scope" was invented > in XVIII century, and this was simply a Galileo scope > with small magnification and with large > object lens diameter. (Approximately of the same type as > the standard straight non prismatic scopes of modern sextants). > These scopes indeed help with horizon or any other object at > night simply because they collect more light. > > Alex. > > On Sat, 25 Jun 2005, george huxtable wrote: > >> Robert Eno wrote- >> >> >> >Has anyone used a night vision scope for conducting star sights at >> >sea? The idea intrigues me and in theory it sounds like it would work, >> >but I do not know anyone who has actually used one at sea. >> >> An interesting question. Presumably you would use it in place of the >> telescope, to show up both star and horizon. Otherwise, how well would >> the >> sight-line of such a night scope be defined? And how would you check for >> index error?. I only ask, because I am quite unfamiliar with such >> instruments. >> >> Could a digital camera be used for the same purpose? Amateur astronomers >> use quite ordinary arrays for looking at stars. >> >> I think one of the difficulties would be the fast motion of the images >> with >> respect to the screen as the vessel wobbled underfoot. The human eye is >> good at assessing the relative positioning of star and horizon, even >> while >> they are whistling across his field of view. An electronic screen could >> find that job to be more difficult. Perhaps some image stabilisation >> would >> be needed also. >> >> But a sextant with lots of electronics attached: wouldn't that be getting >> the worst of both worlds? The most satisfying aspects of a sextant are >> its >> precision and its basic SIMPLICITY. >> >> George. >> =============================================================== >> Contact George at george@huxtable.u-net.com ,or by phone +44 1865 820222, >> or from within UK 01865 820222. >> Or by post- George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 >> 5HX, UK. >> >