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Hi Bill,
I have programmed this using "gnuplot" on Unix, I can output the diagram
in hpgl or postscript. I could post the source (where you can see what
lines to plot), the hpgl and the postscript to this "new place". Please
tell me where this is, as I have lost the link to this place.
Thanks,
Eddie
On Sat, Jan 28, 2006 at 08:37:03PM -0500, Bill wrote:
> > Bill, it wouldn't be too difficult for a bloke of your many talents to draw
> > up a nice fresh one, would it?
>
> Not difficult, just time consuming. According to Chapman's the lines are
> all at 60 degrees angles to the main vertical degree line. What I am not
> clear on is the spacing for a degree of deviation along those 60-degree
> lines. That would have to be retro-engineered. My first guess is that with
> a 60/60/60 triangle the spacing will be identical to the vertical axis. The
> curves of course are what one draws in after finding deviation.
>
> In searching the internet for the Napier Diagram, I ran across a bit of a
> history on him, and some of his other projects. A very clever (brilliant)
> fellow indeed. I would hate to try second guessing him.
>
> If push comes to shove, will indeed do my own. Need to think about
> copyright laws before posting.
>
> Enjoyed your recounting of "men without boards in the companionway?" How
> the heck did they mange to fill the boat water!
>
> "Always step *up* into a life raft." LOL
>
> ============================================================
>
> Off topic, pulled out some more dusty Ansel books this AM. He bemoans the
> "K factor" (to HELP us) in most light meters that can cause 1/3 stop over
> exposure, as well as the f-stops in many of his view camera lenses being off
> for smaller openings (higher f-numbers).
>
> Also tracked down his conversion of foot candles to shutter speed. Foot
> candles (incident light) once reflected yields foot Lamberts (for example
> 100 foot candles reflected off a 50% reflective surface yields 50 foot
> Lamberts. Foot Lamberts divided pi become candles/ft^2, then divided by the
> square root of the f-stop gives the reciprocal of the shutter speed. Pi
> seems to be a kissing cousin of the conversion factor listed in "Pocket
> Reference" of. 0.31831. Wow, a long way to go.
>
> Ansel also stated a Polaroid filter reduced light by about 1 1/3 stops.
> Noticed in the Schneider PDF the number "2" popped up for their "superior"
> filters, but I don't recall the context. It would appear you have some nice
> gear there.
>
> Have a great trip.
>
> Bill
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