NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bygrave Scale Lengths
From: Brad Morris
Date: 2013 Jan 30, 14:40 -0500
From: Brad Morris
Date: 2013 Jan 30, 14:40 -0500
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" <hhew36@gmail.com> 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 >> ---------------------------------------------------------------- >> >> Linked File: https://www.NavList.net/imgx/f1-IMG_2170.JPG >> >> *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 > >
