Starry night Digital is a simplified version.
The problem with Avebury is that there is no definitve viewing point like the stonehenge trilathons.
I worked with Gerald S Hawkins before he died working out the most likely viewing points for major events.
The Coves seem to lunar orientated.
The Kennet avenue twists and turns so much that a lot of alignments can be found depending which stones you stand inbetween.
The section from the Beckhampton Cove along the avenue back to avebury is very straight and appears to be aligned on the summer solstice.
PeteG