Using your data from the navigation stars create a star chart. Rather than measure, to save time look up the RA and Dec of other major stars in the zodiacal and circumpolar constellations and add them to your chart.
1. Measure the distance between +90 degrees and 0 degrees on your graph. Cut a circle out of a second piece of paper twice that distance to give you a horizon for your Planisphere. Overlay it on top of your star chart with Polaris at the correct elevation for your site. Looking at an already assembled Planisphere can you find a combination of date and time that resembles your model?
2. If want to create a working Planisphere there is a link to a labeled star chart with five hundred stars in the Links section below.
3. See this site for pictured directions for making a star chart: https://www.wikihow.com/Make-and-Use-Star-ChartsResults
I used this polar coordinates grid I found on the internet, printed it on paper, aligned the hours of Right Ascention on the grid (seen here) and plotted all of my measurements of the 48 navigation stars I recorded for Activity 12. I kept the navigation star numbers the same as listed on the Wikipeda reference page and used that number next to the plotted stars.
Click each of the following images to see a larger image of them.
I aligned the plotted stars with the date ring of the Planisphere and glued the two disks together.
I used the Planisphere template I had from my Longmont Astronomical Society. We made a lot of Planispheres for an Astronomy Day Outreach Event many years ago to give these to the public. I reused the front, back, and date ring from those Planispheres.
I glued the front and back pieces together and used a rivet to secure the plotted stars to the back of the Planisphere.
Here is the midnight of June 21stars visible:
Here is the midnight of September 21stars visible:
Here is the midnight of December 21stars visible:
Here is the midnight of March 21stars visible:
I took my Planisphere out on October 22, 2024 to see how accurate it is. I found it to be accurate.
