A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: MS-733,Simex,Astra IIIB + sextant calibration
From: Joel Jacobs
Date: 2004 Feb 2, 15:36 -0500
From: Joel Jacobs
Date: 2004 Feb 2, 15:36 -0500
Hi Doug, I went back to sea in NOV of 1978, and only stayed in touch with the Hattori's by snail mail. I don't have any idea what changes were made in standard and accessories after 1978. When the 733 was introduced it was fitted with a 4 x 40, and optional 7 x 35 prismatic. Rather than bore the group, those that want can read about the "No Markings 733" I sold to the retired Navy CAPT. Our ebay store is Land And Sea Collection. That 733 had all the standard features which included the Polaroid lens caps. These caps were also offered on Tamaya's previous premium sextant the MS 636. BTW, we also have a web site of the same name plus .com. Mike Burkes contacted me some weeks back, and I wrote him all I knew about Coast Navigation, Capt. Simonsen, Simex and Jim Tindall who took over the helm from the Capt.. By Navy types I meant rather than USCG or USMM. The latter are big users of the Astra in our maritime academies. You're correct. The difference is the Deluxe has a larger rectangular index mirror as compared to the round one on the standard. The horizon mirror size is the same on both. The Whole View mirror is a no cost option. In regard to measuring sextant error, there should be many firms that use a collimator. Any lens manufacturer should have one, and some large size lens repair shops. It is not an inexpensive process, and IMO not worth the money. All sextants produced after around 1975 were made to a standard of error < 11" of arc. Furthermore, I doubt that there is anyone among us who is more accurate in taking sights than his sextant. The USN found years ago that it took approximately 5000 sights before a navigator became proficient. How many of us have done that many? If you took 6 sights per day, that would be 833 sights or 2 1/4 years. Someone like George Huxtable or Frank Reed should be able to tell you which stars to use that are so many degrees apart so that you could check non-adjustable instrument error by the lunar distance method. I also read somewhere how to do it by setting up a grid on a wall, but I've never been able to locate that source again. Joel Jacobs ----- Original Message ----- From: "Royer, Doug"
To: Sent: Monday, February 02, 2004 2:37 PM Subject: MS-733,Simex,Astra IIIB + sextant calibration > Joel, > Wow,working for the Tamaya Group!That must have been a great experiance. > I looked in the archives also and came up dry.I know I posted the info but > can't remember under what title.So,I'll give you a quick rundown of the > sextant.I ordered and paid for the 733 in 1983 while in Japan.I picked it up > while in Japan in 1984.The polarizing filters you wrote about that one > places on the scopes are the type that I got with mine.I got one for each > scope.I ordered the standard sextant,sight tube,3x scope,shades and mirrors > and opted for a 6x scope to be supplied by a Japanese optics firm and fitted > for the 733.I have to check the paperwork to get the name of the optics > company as I can't remember it.I do know the firm makes high end astromomic > telescopes for the Japanese market.The 6x scope has a very fine internal > cross hair.The optics are 1st quality.The Germans don't have a corner on the > optics market by any means.The Index error is a constant 0.1 off the arc.It > hasn't changed in many years under many differant weather conditions. > I've seen and used a few of the Simex sextants.Good quality instruments > also.Do you know the history of these?Mike Burkes,a fellow listmember,has > one and we were talking of and cxomparing them to the Tamayas in the past. > I remember reading(maybe on Ebay)of the sale of the Tamaya or one like it to > a retired naval officer.Was that you? > The Astra IIIB is an excellant sextant.Especially for the price.I don't know > what you mean by "navy types" in your last post.The men were in uniform so > they were navy.The sextants were purchaced off the shelf and were the Deluxe > model IIIB.They had the whole horizon mirror not the split mirror.I think > the differance between the Standard and Deluxe IIIBs are the size of the > Index Mirror.I may be wrong. > Fred,I made inquires in the past and posted my findings to the list about > calibrateing sextants and was told by more than one person in the industry > no one in the states renders that service anymore.Mr. Luykes may have but he > passed away last year. >