My first stack

Nice first effort, Conan! That image has a certain amount of snap to it, with lots of detail and nice contrast. Both the highlights and dark areas are well represented.

Registax is a complex program, with a lot of buttons and features I've never used. It seems like many of the defaults work well. Here's some tips I've found useful:

1. Choose your own alignment points rather than using the ones selected by the program. Most of the points it selects are just random rather than at well-defined, high contrast image points. Its best to find high-contrast points like the edge of shadows or next to bright crater. Left-click selects a point; right-click deletes it. I've selected as many as 1000 points on the Moon. The more frames and alignment points, the longer it takes to process. One of my runs took over 4 hours.
   
2. After alignment is complete, click the box "Show Registration Graph". It will show a graph of frame quality from highest to lowest as a downward trending line. Sometimes there's an obvious point where the quality does a sudden drop. You may want to set the limit to exclude the frames below the drop-off.
3. After stacking, wavelet processing is where much of the benefit of Registax comes in. Your stacked image will look kind of flat, with muted details. Just play with the wavelet sliders starting with number one. Then hit the Do-All button to see the effect. Make adjustments to the sliders and do-all again. You can definitely run the sliders up too far and won't like the results. There are a number of processing buttons on the wavelets page, right hand side which you can play with as well. When you're satisfied with what you got, hit save.
4. Import your image into a photo editing program for post processing to your liking. I usually adjust levels, crop and some times some color correction.

You may want to read on the Registax website the page about trapping noise as I have sometimes found that technique to be useful.

We look forward to your further efforts. You can even reprocess your first 42 images. Sometimes you can get different results.

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Best Regards,
Russ