Click all images for a larger image.
My first attempt at using my Sundial was on June 18, 2023. I had a cardboard box and used the sepressed crease in box to hold the straw gnomone centered and then rotate the sundial so the 12h was also in the crease.
The yellow line down the crease aligns the crease with the previously determined celestial north direction.
I had trouble leveling the box in this fashion. It was level but the box wanted to poof up.I also had trouble with holding the orientation of the sundial to get an accurate reading of the time. In the image on the right, I used the compass to hold the sundial from rolling.
The time shown was close to the actual time, but not close enough to ensure this sundial was working.
I made several modifications to the previous attempts. The next attempt to use this Sundial was on July 31, 2023.
I replaced the cardboard box with a half-inch thick, MDF board. It was much easier to level. The yellow string indicates the direction of celestial north.
I tried to hold the orientation of the sundial properly with my left hand, while trying to take a picture of the dial with my right hand.
This too did not work well. Not enough precision by holding it to get an accurate reading.
I used the crease in the cardboard (green arrows) to help align the sundial with celestial north. I made the width of the cardboard to be 8-inches, 4-inches on each side of the crease. The orange arrows depict this.
With the yellow string (blue arrows) stretched between the two stakes indicating celelestial north, it was very easy to align the sundial with celestial north.
The two wooden blocks (black arrows) holds the cardboard flat.
I used tape to secure the gnomone base to the crease of the cardboard.
I used a straight pin to hold the face of the sundial to the 40-degree latitude orientation of the sundial. I used a compass to sight this in as best as I could.
The left purple arrow shows the bubble level I used to level the MDF board. The right purple arrow shows the leveling blocks I used to level the board. I also use these blocks to level my telescopes in the field.
Now my sundial is securely held and aligned. I can now make repeated observations without the randomness of the previous two versions.
On August, 19, 2023, I recorded this shadow on my Sundial.
The center time of the Gnomone is:
The low minute value of the Gnomone is 35 min and the high value is 42 min.
(49 - 35) / 2 = 7; 7 + 35 = 42
The center time of the Gnomone is 10:42:00. Adding in the Equation of time adjustment of 39 seconds, this makes the current time, as displayed by the Sundial, 10:42:39 am.
The actual time of this image was 11:45:47 am. Taking into account the hour difference of daylight savings time, the difference between the actual time and the Sundial time, the Sundial is behind the actual time by just 00:03:08. I find this remarkably accurate.
