A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David McN
Date: 2022 Dec 8, 22:58 -0800
I have struggled to find an easy and effective way of planning using the star charts in the nautical almanac. I'm in Latitude 38 S and I judged my SHA to be about 013 for my local time 9pm tonight (GMT 9 Dec, 10:00:00.) I see Fomalhaut has SHA 15 and Dec S29. I judge 15 to be close to 13 so I think it will be a litte further west than my meridian and quite high in the sky. I see Altair has SHA 062 and Dec N9. So I judge it will be well over to the west and lowish.
In fact, while my estimations of altitude are broadly correct, both stars end up with virtually the same azimuth, 281 and 287. So by going around the star chart and planning to use stars separated by SHA differences of at least 45 in this particular example wouldn't give me useful data.
I end up having to work through the planning to find stars that will give usefully spaced azimuths rather than being quickly able to choose the best ones just by eyeballing the star charts.