(07-18-2018, 04:11 AM)Rumata Wrote:(07-18-2018, 03:54 AM)pabrides Wrote: Sooooooo, I just finished the averaging of the sun and moon shots and plotted the same. I came within a quarter mile of the true position. So that was the answer... AVERAGING THE SHOTS.
Sun avg: GMT 13:46:59, Hs 19:06
Moon avg: " 13:51:59 " 35:10.3
Thank you so much, Rumata, for the intriguing nav problem.. I hope you have been working out my CN Challenge problems... they also might have some benefit for those who dabble in actual reductions.
Stay Dry
Joe
Averaging shots...Interesting. Let me try it again. I tried to average LOPs and the result was better than not doing it, but let me try to average the shots. And for the practical purposes, what do you think can be the maximum time span before shots for averaging? 5 minutes, less? Well, of course it would depend on the boat's speed and reliabilty of the shots themselves.
Thanks, Joe. As long as I know that I learn something -the day isn't lost.
Good question... I would assume the closer the better. There is a broad expanse of time during the day when there is a change in rate of elevation. One obvious rate change is just before noon to just after when the sun seems to hang at or near the same elevation for a good deal of time. Much of the mid day has rate change that would be hard to compensate for if the observations were spaced too far apart. According to the graphs Ive seen, the more stable part of the day is early morning and late afternoon, but if you are trying to ascertain midday or noon time by equal altitude the observer is taking shots at the worst change-of-elevation-rate times. Yep - closer is better. One minute between shots is recommended.
joe