Gregorian calendar is the most widely used calendar which counts a year length of about 365.2425 days. It is the modified form of Julian calendar. Differed from the solar calendar by 26 seconds, Gregorian calendar most accurately calculates the time by adding 1 day divergence in each 3,323 years. In other words, Gregorian calendar was developed in order to provide a similarity to the tropical year which defines the timeframe required by the Earth to finish 1 orbit around the sun.
It has a significant historical value as it is the most prevalently used form of calendar. Originally proposed by Aloysius Lilius and later on implemented by Gregory XIII, it was basically the restructuring of Julian calendar.
The Restructuring Mainly Facilitated the Following Factors -
Likewise many other great inventions, Gregorian calendar is also not out of its criticism. Firstly, it is not equilaterally divisible into equal number of days in each month. Each year may start on any given day of a week or a month. The placement of holidays are not specific, rather they are scattered all over the year without any given specification. During Gregory XIII, several changes have been made in order to re-modification of the calendar. The philosopher Auguste Comte explained 365th day as a holiday which must not belong to any day of a week. He then added that the generic year may start with a Sunday which will be specified as the first day of the year, that is, each year will be started with a date as 1st January, Sunday. However, this idea was not accepted in worldwide context.
However, Gregorian calendar does not put much influence in the study of astronomy due to its 10 day gap included with it. Hence, the rationale of calculating space backward in time, the study of astronomy primarily puts its emphasis on the use of Julian calendar.