NavList:

Yesterday was first evening with somewhat clear skies here and Jupiter was in the east, and even the Moon was there, so I got a few runs of the newly refurbished Mk IX. As mentioned in the manual the averager takes forever, those 2 minutes are really long, but in the end it was worth waiting for the result. I found the bubble a little sluggish and I need more training in centering it. A little aiming circle instead of the thin vertical lines would be helpful. Also my old eyes would need a bit more illumination of the bubble to be able to center it better.

I made shots with and without the averager and took readings both from the averager and the scales on the side. This way I got two altitudes from one sighting. The averager reading belongs to a time 57 seconds before shutter closing, while the side readings are from "shutter close".

I shan't bother you with all the numbers, only some results.

The Moon with averager was +0.4 and –0.8 nm. Without averager the errors varied quite a bit more with a median of –2.5 nm from 5 readings.

Juipter with averager was –5.1, –0.1 and –1.0 nm. Without averager the errors were all over the place ranging from outliers at –17, –12.0 and –11.8 nm giving  a median from 7 shots of –5 nm (outliers included) or –1.1 nm (outliers excluded).

Now in the morning Venus was there and with averager had an error of +1 nm (two shots).

In all, the sextant does a fine job and I need more experience with it. This is fun!