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I spent a nice sunny day today plotting some sights I took of Arcturus and Jupiter the other night and then a sun sight today. They all plotted exceptionally tightly for my bubble sextant.
 And since I had nothing better to do and hadn't shot the moon in some time, I dug out some old moon sights from a few years back and re-figured them.
 When I originally shot them, I was at a friend's place in the country and took a quick opportunity to 'get the moon' as I hadn't done that yet. I didn't quite know how to do the moon sight reduction then or the v correction so it was nice to go back and re-do them and brush up all at once. To complicate things more, I had an unknown amount of index error at the time and was trying different numbers to try and get an average. So today I plugged in what I know to be the correct IC and it was good to see all the LOPs move in the right direction and get 'tightish' on the location I had been at when I took the sights. 

Ahhh, fun times, lol.

BigBill,

What's it like to take a sight through a bubble sextant? Must you hold very still to keep the bubble in the center of the circle?

Lou

I have a Link A12 made for use in aircraft. It's not too bad but I find it best to be sitting when I take a sight and I do everything slowly otherwise I end up trying to chase the sun, star etc and moving around. If I'm careful, once it's in the bubble things settle down.

Bigbill,

Do you use the recording drum on the A12? I know there is one but I've never known how they work.

Paul.

(04-04-2017, 11:23 AM)P.Rutherford Wrote: [ -> ]Bigbill,

Do you use the recording drum on the A12?  I know there is one but I've never known how they work.

Paul.

I don't. In fact I remove it since it falls off easily and chips.
The drum was intended to mark multiple sightings of the same body in a short time allowing you to go back later and average them. There is a pencil lead on the sextant that you press to do this. Normally there are 2 or 3 drums so you can take your sightings on different bodies at the same time using a different drum for each. You would have to have the index set at a known start point, later you put the drum back on and rotate it until the pencil lines match up and read each sight off the index.
I just skip the drum and record each sight individually without averaging.

Bill