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Re: Sextant Comparisons -> to Joel Jacobs...
From: Courtney Thomas
Date: 2004 Mar 20, 17:05 -0500
From: Courtney Thomas
Date: 2004 Mar 20, 17:05 -0500
Joel, I have one and hate the color, but am otherwise satisfied. What is "black wrinkle paint" ? Where do I get it and how is it applied for optimal esthetics ? Where can I get a proper scope for CELNAV ? How much ? Appreciatively, Courtney Joel Jacobs wrote: > Fred, > > Your best bet is a Russian SNO-T sextant. They are very underrated, and have > most all the features of the preferred brands, and even come in a smaller > size for convenience. However, most of them are sold with only an > astronomical scope which presents the image inverted, and IMO are useless > for CELNAV. Configured with the 7 x scope, you should be able to buy one for > $250.00 because they are a drudge on the market with out an erect imaging > scope. You can read about them in detail at: > > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3712084763&category=37971 > &sspagename=STRK%3AMESSE%3AIT&rd=1 > > They wont meet your standards for good looks, but you can get some black > wrinkle paint, and make them look as pretty as you like. They are a great > buy. > > Joel Jacobs > > > > ----- Original Message ----- > From: "Fred Hebard"> To: > Sent: Saturday, March 20, 2004 12:15 PM > Subject: Re: Sextant Comparisons > > > >>Doug, >> >>No, I don't collect older equipment. I have been trying to acquire a >>sextant suitable for lunar observations, so I look for sextants with >>defects on Ebay that might still be serviceable. >> >>I have one British Husun that only has the "star scope." It's a 2.5x >>power scope. It's my understanding that a more powerful one would give >>more precise readings. I checked this by buying an old Simex-type >>sextant, which subsequently was sold. I have been looking for another >>Husun with the inverting telescope or another instrument. The Cassens >>& Plath was the first that came up which was suitable. >> >>In comparing the Cassens and Plath to the Husun, I would say, overall, >>that I prefer the Husun at this time. It's prettier, with the >>silver-inlayed arc; this increases my fondness for the instrument. The >>black crinkle finish is nicer than the Cassens and Plath's. All the >>screws are varnished or painted brass; there's no aluminum to corrode >>with steel screws or react with the brass or bronze (There's no >>corrosion on my Cassens and Plath; it doesn't appear ever to have been >>used for extended periods). >> >>The 2.5x scope on the Husun has a very wide field of view, wider than >>the 4x "star scope" on the Cassens and Plath. I have seen no optical >>aberrations in the Husun, while the Cassens and Plath star scope has >>chromatic aberration, which rather surprised me (reddish fringe on the >>bottom of the image and bluish fringe on the top). The aberration >>makes it more difficult to check index error by measuring the sun's >>semidiameter. >> >>The handle on the Husun is straight up and down. This makes some >>lunars easier, whereas the tilted handle on both brands of Plaths, >>while it makes looking at the horizon easier on the wrist, makes lunars >>more difficult. When holding the instrument between shots or while >>waiting, the Husun is less fatiguing to hold >> >>The star scope on the Husun is in close to the horizon mirror. This >>centers weight in the instrument, making it less fatiguing to hold. >>Being close in to the horizon mirror, the smaller mirror does not >>restrict the field of view of the instrument as much as one might >>suppose. I suppose the larger mirrors would be "faster" optically, >>however. >> >>The perceived weight of the two instruments is similar. I have not >>actually weighed them. >> >>The lamp on the Husun can be swung around to illuminate my wrist band >>when recording data. The lamp on the Cassens and Plath is guided to >>illuminate the scales only, making recording data more difficult. >> >>The box on the Husun is significantly smaller than the box on the other >>instruments. >> >>These are my impressions after two days. >> >>Fred >>------------------------------------------------------------------------ >>Frederick V. Hebard, PhD Email: mailto:Fred@acf.org >>Staff Pathologist, Meadowview Research Farms Web: http://www.acf.org >>American Chestnut Foundation Phone: (276) 944-4631 >>14005 Glenbrook Ave. Fax: (276) 944-0934 >>Meadowview, VA 24361 >> >>On Mar 19, 2004, at 5:44 PM, Royer, Doug wrote: >> >> >>>By the way,do you collect older sextants?Don't you also have some older >>>British equipment you wrote about in the past?Just curious. >>> > -- Courtney Thomas s/v Mutiny lying Oriental, NC WDB5619