Admin Edit: This thread was split off from an earlier thread concerning Epicurus' Birthday. In this case I left a copy of the posts in the original location, but let's use this thread to discuss "Astronomy Software." I've previously intended to post about "orreries" (and maybe that exists somewhere, and I just can't find it at the moment). At any rate there's plenty of precedent for Epicureans being interesting in the night sky, so we can talk here about software or other technology to assist in that.
For several years my son and I have looked at the moon most evenings that it's visible. This discussion of the lunar calendar has me intrigued as to what it might be like to tune in more closely to the lunar cycles as another way of being in nature. To that end, I found an app! Oh, the irony....
At any rate, Daff Moon gets my vote as an excellent tool. I've been using it for a few weeks now; my favorite features are a chart showing the phases of the moon, and a "sphere" feature that shows the sun and the moon in a simple 3D view in relation to the ground plane at my location. It has lots more: the sun, the planets, orbits, if those are of interest. Two thumbs up!