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Lesson learned - Rumata - 10-21-2018
Greetings,
Am pretty sure me only had that kind of a problem in calcs, but, anyway, let me share it with you. Just in case.
Using intercept method. Getting wrong fixes . Checked anything a few times, every adding/subtraction. By the way, I knew what the right fix should be. Just doesn't work. Then recollected oldl engineering rule # 0: If something is going wrong-check constants. Anyway, found out that when corrected Declination for proper GMT I added the correction "d" without giving any thought why I am doing it. Just added. In my case it was about 10'. Then, when I checked NA page and looked down the page, I realized that Decl. is decreasing. And as soon as I subtracted "d", everything worked fine. Again, I'm sure you know it and pay proper attention to the "tendency" in Decl. to put a correct sign to "d". Then, when you are using , let say, Pub.229, and correct Hc-then the error in "d" for Decl. does affect Hc. And eventually intercept itself.
Never I imagined this kind of error would affect the intercept so much. In my case it did.
Live and learn. ;> ;>
RE: Lesson learned - pabrides - 10-21-2018
(10-21-2018, 06:47 AM)Rumata Wrote: Greetings,
Am pretty sure me only had that kind of a problem in calcs, but, anyway, let me share it with you. Just in case.
Using intercept method. Getting wrong fixes . Checked anything a few times, every adding/subtraction. By the way, I knew what the right fix should be. Just doesn't work. Then recollected oldl engineering rule # 0: If something is going wrong-check constants. Anyway, found out that when corrected Declination for proper GMT I added the correction "d" without giving any thought why I am doing it. Just added. In my case it was about 10'. Then, when I checked NA page and looked down the page, I realized that Decl. is decreasing. And as soon as I subtracted "d", everything worked fine. Again, I'm sure you know it and pay proper attention to the "tendency" in Decl. to put a correct sign to "d". Then, when you are using , let say, Pub.229, and correct Hc-then the error in "d" for Decl. does affect Hc. And eventually intercept itself.
Never I imagined this kind of error would affect the intercept so much. In my case it did.
Live and learn. ;> ;>
Ive been there and done that.... I still get confused... Especially this time of year when the sun is south of the equator; the declination numbers get bigger - but they get bigger in the negative direction. I really have to think about that twice before it makes sense to me....... Great Post, Rumata. I hope you tried working out my sun sights in my other recent post...
joe
RE: Lesson learned - Rumata - 10-21-2018
(10-21-2018, 09:55 AM)pabrides Wrote:(10-21-2018, 06:47 AM)Rumata Wrote: Greetings,
Am pretty sure me only had that kind of a problem in calcs, but, anyway, let me share it with you. Just in case.
Using intercept method. Getting wrong fixes . Checked anything a few times, every adding/subtraction. By the way, I knew what the right fix should be. Just doesn't work. Then recollected oldl engineering rule # 0: If something is going wrong-check constants. Anyway, found out that when corrected Declination for proper GMT I added the correction "d" without giving any thought why I am doing it. Just added. In my case it was about 10'. Then, when I checked NA page and looked down the page, I realized that Decl. is decreasing. And as soon as I subtracted "d", everything worked fine. Again, I'm sure you know it and pay proper attention to the "tendency" in Decl. to put a correct sign to "d". Then, when you are using , let say, Pub.229, and correct Hc-then the error in "d" for Decl. does affect Hc. And eventually intercept itself.
Never I imagined this kind of error would affect the intercept so much. In my case it did.
Live and learn. ;> ;>
Ive been there and done that.... I still get confused... Especially this time of year when the sun is south of the equator; the declination numbers get bigger - but they get bigger in the negative direction. I really have to think about that twice before it makes sense to me....... Great Post, Rumata. I hope you tried working out my sun sights in my other recent post...
joe
Thanks, Joe. You're right. It is easy to be confused. Especially if the Table is named "Increments and Corrections." For my mind the word "increment" always has a "positive" connotation. ;>
I'm working on a few projects almost simultaneously and, therefore, unable to work your Sun sights. For now. Hope will be able to do it in a future. But...you never know.
Have a good time. Enjoy your sailing.
RE: Lesson learned - Rumata - 11-15-2018
Gentlemen, one more lesson learned ( on my side, of course) . Usage of the Publications 229 or 249 of a non-current (outdated) epoch will noticeably affect the value of Hc. Not too much Z or Zn. And as the result the intercept will be quite different from what it was supposed to be. I used Publications of 1993 and check the data against 2001 edition. For the same LHA Aries Hc differs. Similar situation with LHAs of selected stars.
Just to be aware.
Thank you