NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bygrave Scale Lengths
From: Hewitt Schlereth
Date: 2013 Jan 30, 11:53 -0800
From: Hewitt Schlereth
Date: 2013 Jan 30, 11:53 -0800
Brad, that's the way I would read it. Somewhere there is an F Table. Anyone for Raiders of the Lost Table? :-) Hewitt Sent from my iPad On Jan 30, 2013, at 11:43 AM, "Brad Morris"wrote: > Hewitt > > There is an additional "Table". > > Perhaps that table does show "official instructions". That would be > fantastic! The updated instruction then says > > "Use F-Table when declination is near zero and when the hour angle is near > zero or 90 deg" > > Or did I slaughter that too!? :-? > > Image http://fer3.com/arc/img/122161.img_2161.jpg shows the first half of > the Table. > > Image http://fer3.com/arc/img/122161.img_2162.jpg shows the second half. > > Can you make out what the title of the F-Table is? > > Oh yeah and... Thanks! > > Regards > Brad > On Jan 30, 2013 2:06 PM, "Hewitt Schlereth" wrote: > >> ------------------------------ >> >> Brad, it's been a long time since I did translations from German and I have never had hands on any cylindrical slide rule, in but the phrase, >> >> "Bei d nahe 0 oder t nahe 0 und 90 verwende F-Tafel", >> >> the verb "verwende" means 'use' or 'employ' an 'F-Table', which I would take to mean something ancillary to the main slide rule, like say a printed table. >> >> Hewitt >> >> >> >> Sent from my iPad >> >> On Jan 30, 2013, at 6:21 AM, "Brad Morris" ** wrote: >> >>> Hi Gary >>> >>> Image 122161.img_2160.jpg tells the tale! >>> >>> In it, we see the rules for using the device. Within those rules, we see >>> the standard admonishments for the MHR1, with one major and glaring >>> change. In German, we have: >>> >>> Bei d nahe 0 oder t nahe 0 und 90 verwende F-Tafel >>> >>> Which I loosely translate to: >>> >>> Do not use the slide rule (F-Tafel) when declination is near zero deg or >>> when the hour angle is near 0 or 90 deg. >>> >>> The is no longer any numerical prohibition like 0 deg 20 min or 89 deg 40 >>> min. It just says "near" (nahe). This could be understood to say the same >>> thing, since 20 min is near to zero. >>> >>> But given the precise directions of the MHR1, I would like to think that >>> near now means that the scale has been extended downwards and upwards, as >>> we have discussed, towards 0 and 90 deg. To what value? The images do not >>> reveal this data point. Pity. I'd like to think that it went to within an >>> arc minute, the trick of a tiny offset to include 0 deg 90 deg not >>> withstanding. >>> >>> What do you make of the conversion table, the adjustment knobs and the >>> magnifying glass? Magnifiers are typically associated with verniers and >>> fine graduations. >>> >>> Regards >>> Brad >>> On Jan 30, 2013 12:39 AM, "Gary LaPook" ** wrote: >>> >>>> ------------------------------ >>>> >>>> I am attaching some photos I took of the MHR2 in London in 2009. >>>> >>>> gl >>>> >>>> +++++++++ >>>> >>>> I would be very curious to see what the scale lengths and operating ranges >>>> of the MHR2 table top calculator. Ronald - Do you know these values? >>>> >>>> ++++++ >>>> ---------------------------------------------------------------- >>>> NavList message boards and member settings: www.fer3.com/NavList >>>> Members may optionally receive posts by email. >>>> To cancel email delivery, send a message to NoMail[at]fer3.com >>>> ---------------------------------------------------------------- >>>> >>>> >>>> >>>> *Attached File: 122161.img_2160.jpg** >>>> * >>>> *Attached File: 122161.img_2161.jpg** >>>> * >>>> *Attached File: 122161.img_2162.jpg** >>>> * >>>> *Attached File: 122161.img_2164.jpg** >>>> * >>>> *Attached File: 122161.img_2166.jpg** >>>> * >>>> *Attached File: 122161.img_2167.jpg** >>>> * >>>> *Attached File: 122161.img_2168.jpg** >>>> * >>>> *Attached File: 122161.img_2169.jpg** >>>> * >>>> >>>> : http://fer3.com/arc/m2.aspx?i=122161 >>>> >>> >>> >>> >>> >>> : http://fer3.com/arc/m2.aspx?i=122166 >>> >>> >> >> >> >> >> : http://fer3.com/arc/m2.aspx?i=122168 >> > > > > > : http://fer3.com/arc/m2.aspx?i=122169 > >