DIY Orthographic Sphere

My orthographic sphere is a DIY astronomy tool that "accurately" tracks our sun and local constellations.  Depending on your steady hands, it's reliable year-round for the next thousand-thousand years (give or take a millennium or two).

This is my first attempt at an educational tool so I decided to fabricate an astronomy map in a creative way that can be handheld to track our sun and relative constellations.  No planets, moons, satellites, or comets... sorry for the muggle inadequacies.


How it Works:

main components:
ball: this is your new night sky.
easter egg base: this is your horizon and stand.
screw: your fulcrum for the base of the sky.
blue constellation lines and mapped silver dots... your constellations!
roman numerals: your sun's placeholder for the month of that number, I through XII.

function:
A rotating map of the main constellations in relation to our sun and earthly position.
Pick a Roman numeral and rotate it below the horizon line (sunset). Once your chosen numeral sets, the visible constellations would be visible in our actual night sky until that number rolls back around (dawn).

tips:
draw an appropriate grid onto your hand picked sphere... carefully.
drill extra holes in your base to compensate for whatever latitudes you may be traveling through (the night sky shifts).
draw one constellation at a time. stars first, then branch outward. 
don't literally imagine yourself outside the sphere but instead looking up from your backyard on earth. I know it sounds odd but if you did the former, you may notice space-time would be curved in such a way that it fails to resemble our earthly perspective... and my map would need to be inverted.
but above all, enjoy! IT'S SCIENCE!