Displays the current equation of time and solar declination on a Nokia 5110 LCD. Time is kept by a DS3231 real time clock. The equation of time and declination can be used to determine latitude and longitude at the meridian passage of the sun (aka Local Apparent Noon).
- Raspberry Pi Pico
- ZS-042 DS3231 RTC
- Nokia 5110 LCD with Philips PCD8544 driver
- A sextant
- CircuitPython 8.2.9
- adafruit_ds3231
- adafruit_pcd8544
- 5x8 font
Techniques for using a sextant to determine location at meridian passage are covered in the American Practical Navigator, Chapter 19, Meridian Passage. Another good reference is the Davis Mark 3 Sextant Manual.
This program is expected to be less accurate than most almanacs. Calculations are limited by the single precision of floating point numbers in CircuitPython.
Formulas are taken from Chapters 7, 25 and 28 of Jean Meeus' Astronomical Algorithms (2nd edition), 1998. The low accuracy methods are used.