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The planetarium is based on the HIP (Hipparcos star chart) and displays stars of 5th magnitude or higher (1465 stars), names of famous stars, and lines and names of constellations. The movements of the planets are also reproduced and lines are drawn on the trajectories of their movements. When the application is launched, an earth model is placed 50 centimeters in front of the device, based on the device's position. A celestial sphere with a radius of 200 cm is placed based on the earth model, and stars and planets are placed on the celestial sphere. The radius of the celestial sphere can be zoomed in and out. You can also view the celestial sphere from inside or outside.
# Features
- [x] ARKit reproduces a planetarium.
- [x] The planetarium is based on the HIP (Hipparcos star chart).
- [x] Displays stars (magnitude 5 or higher, 1465 stars).
- [x] Famous stars are labeled with their names.
- [x] Displays constellation lines and names on the celestial sphere.
- [x] Draws azimuth lines on the celestial sphere.
- [x] Displays the sun, moon, and five planets (Mercury, Venus, Mars, Jupiter, and Saturn) and draws lines on their trajectories.
- [x] The Earth model is placed in the center of the celestial sphere with a realistic tesure.
- [x] The positions of the planets are calculated (using the Horizons API) based on actual values.
- [x] Observation locations can be changed (11 locations).
- [x] Date of observation can be changed (2024-2028).
- [x] Time can be increased or decreased with the tap of a button. You can also advance the time automatically.
- [x] Speed adjustment function (minus value for reverse rotation) to adjust the movement of the celestial sphere.
- [x] Zoom function (zoom in/out) to change the size of the celestial sphere.
- [x] Toggle to show/hide text information and coordinate axes.
- [x] Drag the earth model to move the position of the celestial sphere.
- [x] Change the background color by identifying day and night.

## How to use
1. when you launch the application, you will be asked for "permission to use camera" at first launch. If you allow it, an ARKit session will start.
2. The earth model and coordinate axes are placed 100 cm in front of the device, based on the device's position.
3. Tap the "Load Stars" button to load the star and planet models. Please wait a moment.
4. After loading, the stars, planets and constellation lines are drawn on the celestial sphere.
5. By moving the device, the celestial sphere (planetarium) can be observed from various angles and positions.
6. Tap the buttons at the bottom of the screen to adjust speed and zoom.
7. You can change the observation point from the menu in the upper right corner of the screen.
1. Tokyo (Japan)
2. Greenwich (England)
3. Dakar (Senegal)
4. Cairo (Egypt)
5. cape town (South Africa)
6. Melbourne (Australia)
7. Wellington (New Zealand)
8. Honolulu (USA)
9. Los Angeles (USA)
10. Vancouver (Canada)
11. Buenos Aires (Argentina)
8. Observation dates can be changed from the Set Date button. (2024 - 2028)
9. You can show/hide text information and coordinate axes from the menu in the upper right corner of the screen.