Moonlight illuminating the observatory with star trails behind

Continuing on from yesterday's post about finding the celestial south pole, this time I wanted to experiment further with star trails and capture the observatory in the centre of the shot.

I came back to the observatory for the second night of my star trail attempts. This time I wanted to get the south celestial pole directly above the observatory. So. I did my calculations by using the southern cross as my guider and using my laser to line up my frame. To calculate south using the southern cross you have to take the longest length of the cross and go 3.5 times to the direction its pointing and that should be your south. Here's some more info on how to find it.

Experimenting with red light on the observatory

As you can see I was just out but I was still pretty happy with how the star trails came out. On this occasion I took 200 consecutive photos of 20 second exposure each with a 2 second interval to let the camera reset. I stitched the photos together in post processing using an amazing program called StarStax and here's what I came up with. I also experimented with the light of the observatory, using only the moon light in my first shot and the red light of the observatory on my second. Which do you guys prefer?