NavList:

From: Brad Morris <bradley.r.morris@gmail.com>
Subject: [NavList 22169] Re: Bygrave Scale Lengths
To: garylapook@pacbell.net
Date: Wednesday, January 30, 2013, 11:43 AM

---

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 https://NavList.net/img/122161.img_2161.jpg shows the first half of the Table.

Image https://NavList.net/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---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
>> *
>> 
>> : https://NavList.net/m2.aspx?i=122161
>> 
> 
> 
> 
> 
> : https://NavList.net/m2.aspx?i=122166
> 
> 

: https://NavList.net/m2.aspx?i=122168

: https://NavList.net/m2.aspx?i=122169