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HP-71B Software for navigation
07-19-2019, 07:59 PM
Post: #21
RE: HP-71B Software for navigation
I'm familiar with the K. A. Zischka book, Astronavigation a method for determining exact position by the stars published by Springer;
[attachment=7487]
Is there a subtitle & publisher for Bobby Schenk's book?

BEST!
SlideRule
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07-20-2019, 04:59 AM
Post: #22
RE: HP-71B Software for navigation
(07-19-2019 07:59 PM)SlideRule Wrote:  I'm familiar with the K. A. Zischka book, Astronavigation a method for determining exact position by the stars published by Springer;

Is there a subtitle & publisher for Bobby Schenk's book?

BEST!
SlideRule

Hi,

This book is from: Bobby Schenk; Astronavigation: ohne Formeln - praxisnah published by Delius Klasing Verlag, 2018; ISBN 978-3-7688-0259-8

[Image: 51PwZFAMygL._SX331_BO1,204,203,200_.jpg]

There is also a small chapter with steering by stars, moon and planets. He wrote, that from all his positions he made roughly 400 with sun at noon, 800 with sun, 100 with moon, 50 with planets and 50 with stars.

For my measurements I'll additional take a printout for this week from the very fine online almanac: http://www.tecepe.com.br/scripts/AlmanacPagesISAPI.dll
with me. So I can manual calculate the position by moon i.e.

regards
Erwin
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07-20-2019, 12:44 PM
Post: #23
RE: HP-71B Software for navigation
Thanks (dank) !

SlideRule
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08-11-2019, 11:08 AM (This post was last modified: 08-11-2019 11:09 AM by Erwin.)
Post: #24
RE: HP-71B Software for navigation
[attachment=7596]Hello,

I'm back from my first sailing trip in Croatia - it was wonderful but no typical for astro navigation it's more a inshore navigation situation. But it was only to test the program in reality and myself in handling the sextant.
During the trip I had several possibilities to play around with my Mark 3 sextant and my HP71b program (sunsight). Handling and results are as good as for a first timer in astro navigation. So I decided to pull the program a step further:
  • small improvements for data input (actual date, sextant input data, ...)
  • choose short or extended result
  • possibility to save several results so there is no need to write them down immediatly
  • possibility to make formated printouts with my thermo printer
This will be my "winter project" this year. For myself - improve the handling with the sextant.

A possible project in the future could be a little program that helps calculate for inshore navigation based on the book "the calculator afloat" (bearing, distance, dead reckoning, tidal, ...).


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08-11-2019, 04:05 PM
Post: #25
RE: HP-71B Software for navigation
Congratulations, both on surviving your initial trip using 'old school' navigation equipment, and also for proven success in re-establishing a working navigation system on your 71B!

Was the final program you used from the Schenk book, from the translated 41 ROM (using the 41 emulator) or some hybrid you created? Hopefully, once enhanced as you suggest above, you'll be willing to post and share your programs - you never know, there could be other brave souls wanting to use pre-GPS navigation too.

Well done Erwin, thanks for sharing your planning and success stories here.

--Bob Prosperi
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08-11-2019, 04:44 PM (This post was last modified: 08-11-2019 05:24 PM by Erwin.)
Post: #26
RE: HP-71B Software for navigation
(08-11-2019 04:05 PM)rprosperi Wrote:  Congratulations, both on surviving your initial trip using 'old school' navigation equipment, and also for proven success in re-establishing a working navigation system on your 71B!

Was the final program you used from the Schenk book, from the translated 41 ROM (using the 41 emulator) or some hybrid you created? Hopefully, once enhanced as you suggest above, you'll be willing to post and share your programs - you never know, there could be other brave souls wanting to use pre-GPS navigation too.

Well done Erwin, thanks for sharing your planning and success stories here.

Hi Bob,

thanks ... my actual program is this from post program it is my basic program based on the Excel from Andy. It is not optimized code, cause it is about 25 years ago I programmed in Basic. The 41 emulator I'll give another try in autumn, cause I have to dig in the "art of programing". Would be fine to find a possibility to start the input for the HP41 program from basic, so I have a common interface. But priority is develop my Basic program.
Of course I''ll share my program again if it is advanced.

Edit Why I concentrate on sun navigation? Cause it is the most Bobby Schenk used on his trips.
Bobby Schenk calculates in a similar way like in my bass program with the necessary tables. So it is more or less the same method. I had as a backup the ephemerides data (Alamanc) for the sailing trip with me (see attachment).

EDIT 2 There are 2 other different books which, in my opinion are essential to understand navigation.
  • The calculator aflot (it is manly the theory and examples)
  • Calculator navigation (theory, examples and HP67 programs)
What I'm not able to do is, the HP67 programs convert into HP71 Basic - that would be the ultimate program :-)

best regards
Erwin


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09-01-2019, 11:41 AM (This post was last modified: 09-01-2019 11:44 AM by Erwin.)
Post: #27
RE: HP-71B Software for navigation
Dear auditorium,

I'm working on my sunlight program to expand the function I wrote in my past post and fiddling around with the Date and Time presentation. Cause I used the EXCEL from blackbearing straight forward, the program split up days, month, years and hours, minutes, seconds in single variables for calculation (I do this from DATE$ and TIME$).
For my next step in expanding the program I want to save the input data and results in a SDATA file and so keep those variables (not using TIME$, DATE$ and therefore a DATA file).
The problem I face is, that when I want to show date and time again on display, those with single digits are presented without a leading ZERO. It looks strange but it is not an error.

Example for time: Variable B(2), B(3), B(4) ... are representing hours:minutes:seconds (similar for the date).
Code:
STR$(B(2))&":"&STR$(B(3))&":"&STR$(B(4))
There is no fault in the figures of the result but it looks strange.
Code:
2019/9/9 - 12:5:23

I tried to overcome this with the USING statement, cause it is only for showing in the display but without success. The solution I don't want to use is, to convert it to another format (and handle it with the JPC ROM possibilities Date, Time conversion tools)

Has anybody a solution for this - "I can't see the wood cause all of the trees" (an Austrian saying)

NEW: I started an additional function LAN (local apparent noon) with regression analysis. So to have two possibilities for steering by sun. The core program is for all those calculations.

best regards
Erwin
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09-01-2019, 02:19 PM
Post: #28
RE: HP-71B Software for navigation
(09-01-2019 11:41 AM)Erwin Wrote:  The problem I face is, that when I want to show date and time again on display, those with single digits are presented without a leading ZERO. It looks strange but it is not an error.

Example for time: Variable B(2), B(3), B(4) ... are representing hours:minutes:seconds (similar for the date).
Code:
STR$(B(2))&":"&STR$(B(3))&":"&STR$(B(4))
There is no fault in the figures of the result but it looks strange.
Code:
2019/9/9 - 12:5:23

I tried to overcome this with the USING statement, cause it is only for showing in the display but without success.

A simple solution: replace STR$(x) with this user function FNS$(x):
Code:
DEF FNS$(X)=("0"&STR$(X))[1+(X>=10)]

J-F
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09-01-2019, 04:42 PM
Post: #29
RE: HP-71B Software for navigation
(09-01-2019 02:19 PM)J-F Garnier Wrote:  
(09-01-2019 11:41 AM)Erwin Wrote:  The problem I face is, that when I want to show date and time again on display, those with single digits are presented without a leading ZERO. It looks strange but it is not an error.

Example for time: Variable B(2), B(3), B(4) ... are representing hours:minutes:seconds (similar for the date).
Code:
STR$(B(2))&":"&STR$(B(3))&":"&STR$(B(4))
There is no fault in the figures of the result but it looks strange.
Code:
2019/9/9 - 12:5:23

I tried to overcome this with the USING statement, cause it is only for showing in the display but without success.

A simple solution: replace STR$(x) with this user function FNS$(x):
Code:
DEF FNS$(X)=("0"&STR$(X))[1+(X>=10)]

J-F

Hello,

thank you very much - indeed a small and elegant solution ... tested and runs as you said :-)

best regards
Erwin
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09-01-2019, 08:54 PM
Post: #30
RE: HP-71B Software for navigation
(09-01-2019 02:19 PM)J-F Garnier Wrote:  A simple solution: replace STR$(x) with this user function FNS$(x):
Code:
DEF FNS$(X)=("0"&STR$(X))[1+(X>=10)]

J-F

Elegant!

I saw Erwin's question this morning, but no time to reply, I was going to look thru some options to offer later today, but it would not have been as nice as this. I really like the [1+(X>=10)] sub-string use. A perfect example of the rich and powerful BASIC in the 71B.

--Bob Prosperi
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