I am trying to teach myself Celestial Navigation, Have read lots of books, but when I try to use my ARTIFICIAL HORIZON to get a fix, My numbers do not seem correct. I half the sextant reading, apply no dip, my index error is 0, then I apply my total correction. BUT>>>>>, when I do a sight reduction based on my Acual Lat and Lon, I am about 800 miles off Obviously something is WRONG. Here is an example of a fix. Sun LL Time 13 22 29 UTC Sextant Reading 61 deg 28' Observed 30 deg 44' (above halved) No dip, No index error Alt correction +14 deg 40' 44 deg 48' I am at latitude 39.52N 75 08W Does this seem like the correct reading???????????????????????? If not what am I doing wrong ??????????????????????????????? I'm sure it's just easier to buy a chart plotter. Thanks for all your help. Bill
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don't have the books close by but -
I think you need to cut the observed angle in half when using the artificial horizon.
I think you need to cut the observed angle in half when using the artificial horizon.
Looks like a time zone error
Hi Bill, Are you applying your time zone correct? (TZ =+5) If the time of obs was 13 22 29 utc then local time would be 20 22 29 or after sun set. Altitude of the sun is stated at 14 40. Maybe time of obs was 13 22 29 local then 20 22 29 is utc or gmt. An 800 mile error sounds like 1 time zone off.
Hi Bill, Are you applying your time zone correct? (TZ =+5) If the time of obs was 13 22 29 utc then local time would be 20 22 29 or after sun set. Altitude of the sun is stated at 14 40. Maybe time of obs was 13 22 29 local then 20 22 29 is utc or gmt. An 800 mile error sounds like 1 time zone off.
But is it not daylight savings time now?
so tz = +4???? the error is the correct direction for a time boo boo
so tz = +4???? the error is the correct direction for a time boo boo
Do I need the altitude correction
When I use the ARTIFICAL HORIZON??? I think that is where my beggest problem is. Bill
When I use the ARTIFICAL HORIZON??? I think that is where my beggest problem is. Bill
Bill ,I think I might have part of the answer.
Yuo said you were taking sun sights LL. With the artificial horizon you super impose the images don't balance one on top of the other and forget the altitude correction I don't think it is needed. Edit to add; 40'+44'=1 d 24 ' so your 44d should be 45
Yuo said you were taking sun sights LL. With the artificial horizon you super impose the images don't balance one on top of the other and forget the altitude correction I don't think it is needed. Edit to add; 40'+44'=1 d 24 ' so your 44d should be 45
Found my problem
I added 14 degrees 4 min for my altitude correction not 14.4 minutes. My error is now 1.1 mile away not 839 miles towards!! I can live with that.
I added 14 degrees 4 min for my altitude correction not 14.4 minutes. My error is now 1.1 mile away not 839 miles towards!! I can live with that.
If I don't use the altitude correction
My sight reduction is 15.5 miles away. I guess the altitude correction is necessary.
My sight reduction is 15.5 miles away. I guess the altitude correction is necessary.
Bill...
What model sextant do you have? I was thinking about getting one. Who konw when electrical issues could crop up? ;D I was looking at the Davis MK15 or MK25. Not ready for a really nice, expensive sextant. We'll see if I can get the hang of the Davis one's first.
What model sextant do you have? I was thinking about getting one. Who konw when electrical issues could crop up? ;D I was looking at the Davis MK15 or MK25. Not ready for a really nice, expensive sextant. We'll see if I can get the hang of the Davis one's first.
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