Accuracy of data
The times of sunset, sunrise, and related data, as quoted on the NRC web pages are computed using standard scientific formulas, adopted by the national almanac offices of the United States and the United Kingdom and used worldwide. The times computed by our web pages are considered accurate to ±2 minutes, in the time period 1900–2100.
The NRC does not collect or maintain records of solar phenomena such as observed times of sunrise, sunset and twilight. Since the relevant data can be computed for past or future dates to sufficient accuracy, such observations are not routinely made.
Certification of data
The NRC can provide a written certificate to confirm that the computations obtained through this website are computed using standard scientific formulas and that the calculated times are accurate to ±2 minutes (in the period 1900–2100). This certificate, signed by a professional astronomer, whose education and qualifications will be stated, should be useful as legal evidence of the data.
Please provide up to 10 working days for your request to be processed.
Fee for certification
A fee of $340 + HST will be invoiced for each such certificate.
Dr. David Bohlender
Herzberg Astronomy and Astrophysics Research Centre