Click on each image to see a larger image
In the beginning, I made this hand held transit quadrant. Although it was functional, it did not have the accuracy that I needed for this Activity. So I scrapped this idea for the following Quadrant I found online.
I bought the aluminum to build this quadrant. After making my hand held quadrant in the first picture, my thoughts changed to a hybrid, combining the simplicity of both designed as seen in the above two pictures.
I printed the right angle templates to support the two aluminum pieces. The templates are found in this PDF File.
I printed the scales from the second image quadrant, that were included in the instructions. I printed them to a scale where the azimuth scale was about 8 inches in diameter. These templates can be found in this PDF File.
I used 1/8 inch thick masonite board for the altitude protractor and the right angle supports.
I used contact cement to glue the scales to the azimuth base. The extended line is the north-south line and needs to be aligned on the celestial north pole. From Activity 1, this is a 14 degree offset to the west from magnetic north. This will help me align the quadrant in the field.
I purchased a new tool to square up the right angle supports. I've always wanted this tool for other woodworking projects. So I bought it now for this project.
I used my hand mitre box and a hacksaw to cut the two aluminum pieces to support the altitude protractor. The shorter piece is 4 inches line and the longer piece is 8 inches long. The measurements for the original quadrant can be found in this PDF File. These dimensions are in millimeters.
It was warm here in Colorado on Sunday January 21, 2024. A balmy 53 degrees. I went out in thee driveway and fabricated all the parts I needed.
I added 4 feet to the azimuth base. I will use wedged door shims to level this base before use.
To ensure the base and upright aluminum pieces were at right angles, I clamped them to a large square. I then drilled holes and used 1/8 inch pop rivets to secure the right angle braces to the aliminum pieces.
This is how the vertical shaft turned out.
This is the finished quadrant. I used zip ties to secure the spotyting tube to the top of the azimuth protractor.
I used the contact cement to clue the altitude scale to the protractor. I took great care to ensure it is at right angles to the site tube.
I used kite string to make a plumb bob with a heavy nut as the weight.
The azimuth scale.
You can see the 1/4 inch bolt that pivots the azimuth of the quadrant.
I secured a thin wire to the front of the aluminum to help read the azimuth angle. I taped this wire to the base of the 4 inch piece.
The backside of the altitude protractor. I added two nuts to make it stand off the upright piece. This helps the plumb bob nut dangle free.
I used the quadrant for the first time on January 28, 2024. I measured the altitude of Ploaris and got a reading of 38.5 degrees. It should have been 39.9 degrees.
What I noticed what that I needed the wingnut tightened enough to help hold the altitude protractor in a position without it rotating when I let it go. This pinched the plumb bob string that contributed to the off reading in altitide.
I looked through all my part drawers and found a larger washer I could tie the plumb bob string too and it would rotate freely around three smaller washers inside this larger washer
and when you tightened the wingnut, it titghtened on these three smaller washers to add friction to the altitude protractor.
I tried this out on January 30, 2024 and the altitude of Polaris now measured just short of the 40 degree mark on the scale. This was a great addition to my quadrant and added the precision I wanted in this instrument.
