I did this as a 20-min "bulb" exposure with a Sigma 18-75, f/2.8, ISO 100. I think it might work better as an interval photo, which could reduce the ambient bright light. Thoughts?

Here.

Nice. I like the light on the tree tops.

Thank you very much!

Yeah, I really like this. Are you using Photoshop, and do you know how to use Statistics | Maximum to stack for trails? I really like the look but I think you're right, sequences might be even better.

I'm using LightRoom. I found the method here today: An Introduction to Star Trail Photography Review - Method I: Exposure Stacking | PentaxForums.com Reviews - planning on trying that next.

I guess that's the same general idea. I don't have LR so I don't know if it has the same features. In Photoshop you can use File | Scripts | Statistics to set the stacking mode for a set of layers, and setting the mode to Maximum does the same as the Lighten blending mode described in your link. However there's no need to iterate through groups of layers, you can apply it to all of them at once. This one was done with 30-second exposures -- lots of files, but you don't go berserk if someone walks by with a flashlight and ruins a 30-second exposure. A 20-minute one, though, I might get violent. (Especially since the ruiner would doubtless be me.)

https://rickwayne.zenfolio.com/astrophotos/h86f1becf

Oh very cool! Looking through your photos now. Very nice selection.

I keep some of mine here: Jonathan Watson (MichianaPhotog) Photos / 500px