04-30-2020, 12:37 PM
(This post was last modified: 04-30-2020, 01:22 PM by CarlosPindle.)
Ray, I think you're correct that the Index Correction they're speaking of is what must be added to the Hs. They're calling it Index Correction and not Index Error.
My complaints are the time format using a hyphen is never done. The confusion of using Index correction is never done and should be stated as Index error. These factors lead to a non-standard way of performing a sight reduction and aren't instructive.
That said, Ho= 13° 46.5'
Hs= 13° 39.4'
+ 0° 02.3' (Index correction)This IS NOT the same as IE
- 0° 07.6' (Dip correction)
+ 0° 12.4' (Altitude correction for SD, Parallax, Refraction)
--------------------------
13° 46.5' = Ho
Hc= 13° 54'
Zn= 122.7° (call it 123°)
Intercept= 8.3' Away
Correct answer is "C"
The ONLY way to get the correct answer is to use an Hc of 13° 54.8' which you can only get using the Hc formula with the following particulars;
DR Latitude= 27°
Declination= S 21° 00.8'
LHA= 299°
Look at the 4 possible answers. Zn is the same in all answers. We know that B and D are wrong. A & C? From our laborious reduction we can tell that our Intercept is AWAY. Even if we use an Ho of 13° 46.5' or 13° 47' or 13° 46' we notice these results point to 8.3' AWAY.
So "C" is the correct answer.
I think the question is more particularly suited for the plotting of an oil rig. If I could get figures that accurate I must be doing NOTHING as the ocean is perfectly calm, no wind, perfect temperature, and I'm really good at taking a Sun sight!
This wont make anybody happy but the mysterious Ho-229 (alright...Pub. No. 229) is something I seen with my eyes, looked at, and then gave up any hope of wanting or trying to understand. 229 might give the answer they want but the added corrections are beyond me. I just want an LOP within a few nm of my location. An Intercept 8.3 nm Away or Towards?! Are you nuts?! Just use 8 nm Away as we can't plot with that kind of accuracy.
Did this solve the question? Hopefully.
Carlos
My complaints are the time format using a hyphen is never done. The confusion of using Index correction is never done and should be stated as Index error. These factors lead to a non-standard way of performing a sight reduction and aren't instructive.
That said, Ho= 13° 46.5'
Hs= 13° 39.4'
+ 0° 02.3' (Index correction)This IS NOT the same as IE
- 0° 07.6' (Dip correction)
+ 0° 12.4' (Altitude correction for SD, Parallax, Refraction)
--------------------------
13° 46.5' = Ho
Hc= 13° 54'
Zn= 122.7° (call it 123°)
Intercept= 8.3' Away
Correct answer is "C"
The ONLY way to get the correct answer is to use an Hc of 13° 54.8' which you can only get using the Hc formula with the following particulars;
DR Latitude= 27°
Declination= S 21° 00.8'
LHA= 299°
Look at the 4 possible answers. Zn is the same in all answers. We know that B and D are wrong. A & C? From our laborious reduction we can tell that our Intercept is AWAY. Even if we use an Ho of 13° 46.5' or 13° 47' or 13° 46' we notice these results point to 8.3' AWAY.
So "C" is the correct answer.
I think the question is more particularly suited for the plotting of an oil rig. If I could get figures that accurate I must be doing NOTHING as the ocean is perfectly calm, no wind, perfect temperature, and I'm really good at taking a Sun sight!
This wont make anybody happy but the mysterious Ho-229 (alright...Pub. No. 229) is something I seen with my eyes, looked at, and then gave up any hope of wanting or trying to understand. 229 might give the answer they want but the added corrections are beyond me. I just want an LOP within a few nm of my location. An Intercept 8.3 nm Away or Towards?! Are you nuts?! Just use 8 nm Away as we can't plot with that kind of accuracy.
Did this solve the question? Hopefully.
Carlos