Hello All, I have been exploring the wonderful world of vertical sundials, thanks in large part to François Blateyron's wonderful Shadows program. Since it has been so cold outside I have been experimenting with prototypes inside the house on my sunny windowsills. I found right away (which I had suspected anyway) that my sunny South windowsill points slightly to the East of South, as I had to "cock" my direct south vertical to the left to get the correct time reading.
I have since figured out how to find the meridian with respect to said windowsill by putting concentric circles on a card, erecting a pin gnomon, aligning it with my windowframe, and marking the shadows throughout the day as they crossed the lines. A wonderful moment of, as they say, illumination to be sure. So, now I am experimenting with vertical decliners... I have two other windows I would like to experiment in, one facing slightly N of East, and the other facing slightly S of West. The noontime sun is not available so I don't think the pin-card trick will work. I need a good simple method to find the declination of these two windowsills, any ideas? I especially like the pin-card method because it is so simple that a potential remote customer could print out a sheet and perform it himself to give me the declination prior to production of a dial. I imagine that some of you have dealt with this issue before. My brother lives right on the ocean in California (great view!), and I would like to make him a West facing vertical declining dial that will be outside, but oriented to the axis of his house. It won't be mounted on a wall, so minor adjustment will be possible - ultra-precision is not really required in this case. If he could perform a simple exercise like the pin-card, using his window frame as the benchmark with respect to the axis of his house, I could make a dial for him without having to go all the way out there. Can anyone offer any solutions?
