Any HP-25c schematics?

[Thomas Klemm]

(08-31-2018 07:53 PM)SlideRule Wrote:  Can be downloaded from archive.org as NTRS-1978002312 LORAN Time Difference.

Thanks for the link to the program.

These formulas are used:

\(
\begin{align*}
\beta_T&=\tan^{-1}[C\tan(\Phi_T) ] \\
\beta_R&=\tan^{-1}[C\tan(\Phi_R) ] \\
X &= \cos^{-1}[\sin(\beta_R)\sin(\beta_T)+\cos(\beta_R)\cos(\beta_T)\cos(\lambda_R-\lambda_T)]
\end{align*}
\)

But we can factor out \(\cos(\beta_R)\cos(\beta_T)\) and get:

\(X = \cos^{-1}[\cos(\beta_R)\cos(\beta_T)(\tan(\beta_R)\tan(\beta_T)+\cos(\lambda_R-\lambda_T))]\)

Hence we can avoid calculating \(\sin(\beta_R)\) and \(\sin(\beta_T)\) since \(\tan(\beta_R)\) and \(\tan(\beta_T)\) have already been computed.

This makes the program a bit shorter:

Code:

01: 24 06    RCL 6          C
02: 24 01    RCL 1          Φ_T                 C
03: 14 06    f tan          tan(Φ_T)            C
04:    61    ×              C tan(Φ_T) = tan(β_T)
05:    31    ENTER          tan(β_T)            tan(β_T)
06: 15 06    g tan⁻¹        β_T                 tan(β_T)
07: 14 05    f cos          cos(β_T)            tan(β_T)
08: 24 06    RCL 6          C                   cos(β_T)            tan(β_T)
09: 24 03    RCL 3          Φ_R                 C                   cos(β_T)            tan(β_T)
10: 14 06    f tan          tan(Φ_R)            C                   cos(β_T)            tan(β_T)
11:    61    ×              C tan(Φ_R)          cos(β_T)            tan(β_T)            tan(β_T)
12:    31    ENTER          tan(β_R)            tan(β_R)            cos(β_T)            tan(β_T)
13:    22    R↓             tan(β_R)            cos(β_T)            tan(β_T)            tan(β_R)
14: 15 06    g tan⁻¹        β_R                 cos(β_T)            tan(β_T)            tan(β_R)
15: 14 05    f cos          cos(β_R)            cos(β_T)            tan(β_T)            tan(β_R)
16:    61    ×              cos(β_R)cos(β_T)    tan(β_T)            tan(β_R)            tan(β_R)
17:    22    R↓             tan(β_T)            tan(β_R)            tan(β_R)            cos(β_R)cos(β_T)
18:    61    ×              tan(β_R)tan(β_T)    tan(β_R)            cos(β_R)cos(β_T)    cos(β_R)cos(β_T)
19:    21    x<>y           tan(β_R)            tan(β_R)tan(β_T)    cos(β_R)cos(β_T)    cos(β_R)cos(β_T)
20:    22    R↓             tan(β_R)tan(β_T)    cos(β_R)cos(β_T)    cos(β_R)cos(β_T)    tan(β_R)
21: 24 04    RCL 4          λ_R                 tan(β_R)tan(β_T)    cos(β_R)cos(β_T)    cos(β_R)cos(β_T)
22: 24 02    RCL 2          λ_T                 λ_R                 tan(β_R)tan(β_T)    cos(β_R)cos(β_T)
23:    41    -              λ_R-λ_T             tan(β_R)tan(β_T)    cos(β_R)cos(β_T)
24: 14 05    f cos          cos(λ_R-λ_T)        tan(β_R)tan(β_T)    cos(β_R)cos(β_T)
25:    51    +              tan(β_R)tan(β_T)+cos(λ_R-λ_T)           cos(β_R)cos(β_T)
26:    61    x              cos(β_R)cos(β_T)(tan(β_R)tan(β_T)+cos(λ_R-λ_T)) = cos(X)
27: 15 05    g cos⁻¹        X
28: 24 05    RCL 5          A(rad)  X
29:    61    ×              d = AX
30:    74    R/S            d
31: 24 00    RCL 0          T_m   T_s
32:    41    -              T_s-T_m

Example

21282.339
π
×
180
÷
STO 5

0.99664767
STO 6

39.1930
→H
STO 3

82.0615
→H
STO 4

34.034604
→H
STO 1

77.544676
→H
STO 2

f CLEAR PRGM
R/S

2317.7679

Cheers
Thomas