Solar Calendar

Dhristi JEE 2022-24

Solar Calendar Meaning

A solar calendar can be best understood by visiting Jantar Mantar (Delhi, Jaipur). 

There was a time when the inclination of sun rays helped people determine the time. Moreover, it also helped people determine the occurrence of an eclipse or any other happenings.  

Usually, a solar calendar helps determine the occurrence on the basis of the time the earth takes to revolve around the sun.

In short, we can say that the solar calendar is a method of measuring and recording the time periods on the basis of the time earth takes to revolve around the star (Sun).

On this page, you will understand solar month, lunar calendar, and solar calendar.

What is a Solar Calendar?

A solar calendar is a calendar, the dates of which point to the season. They are almost equal to the apparent position of the Sun relative to the stars. 

  • The Gregorian calendar is widely accepted as a standard calendar in the world.

  • The Gregorian calendar is a well-known example of a solar calendar. 

  • Another important type of calendar is the lunar calendar.

  • In a lunar calendar, months correspond to cycles of Moon phases. 

  • However, the months of the Gregorian calendar never correspond to cycles of the Moon phase.

There are various types of calendars that help determine the solar month; these are as follows:

Examples of Solar Calendars

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1. Tropical Solar Calendars

If the position of the world in its orbit around the Sun is estimated with reference to the Equinox, the purpose at which the orbit crosses the equinoctial circle, then it's dates accurately indicate the seasons. 

It means they're synchronized with the declination of the Sun. Such a calendar is named a tropical solar calendar.

2. Sidereal Solar Calendars

When the position of the Earth is estimated with respect to the fixed stars, the dates indicate the zodiacal constellation near which the Sun can be found. 

This type of calendar is the sidereal solar calendar.

3. Lunisolar Calendar

Lunisolar calendars are lunar calendars. As a rule, lunisolar calendars are the additional intercalation that keeps a rough synchronization with the solar year; also, with the seasons. 

Ordinarily, a lunisolar calendar has a whole number of lunar months. However, it can't indicate the position of Earth on its revolution around the Sun. The same is with a solar calendar.

Lunar to Gregorian Calendar

Firstly, Egyptians developed the solar calendar to use the annual appearance of the Dog Star - Sirius.

  • Sirius coincided with the yearly flooding of the Nile River, as a focal point. 

  • However, the Egyptians didn’t consider the extra part of a day in their 365-day calendar. 

  • Later, Julius Caesar in favor of the Julian Calendar replaced the Roman republic calendar, based on the Lunar Calendar of the ancient Greeks.

  • Further, the Julian Calendar allowed for February as leap year; also, made the solar year too long by adding a quarter of a day annually. 

  • By then, in the 16th Century, the additional time accumulated to form an error of around 10 days which was improvised in the form of the current Gregorian Calendar.

Solar Years Month

With the help of the solar calendar, we can predict the time period in which the sun sets and rises throughout the day. Besides this, throughout the year, we can also determine the occurrences of the lunar and solar eclipse.

Though the measuring of time started in India; so how the time determination occurred, let’s understand it:

Maharaja Jai Singh II of Jaipur established five Jantar Mantar in the early 18th century, the cities are:

  • New Delhi

  • Jaipur

  • Ujjain

  • Mathura

  • Varanasi;

These five were completed between 1724 and 1735.

The Jantar Mantar monuments have Samrat Yantra, Jai Prakash, Ram Yantra, and Niyati Chakra. Each of these is employed for various astronomical calculations. 

The fundamental objective of the observatory was to compile astronomical tables. Also, to predict the days and movements of the sun, moon, and planets.

The List of Instruments Involved are:

  • Samrat Yantra

  • Jai Prakash Yantra

  • Disha Yantra

  • Rama Yantra

  • Chakra Yantra

  • Rashi Valaya Yantra

  • Dingash Yantra

  • Utaansh Yantra

Solar Years Month

Earth's revolution around the Sun defines the year in the Western World .Therefore, the earth's revolution is referred to as a ´Solar Year´. However, several varieties of Solar years exist:

  1. Tropical Year

A Tropical Year is derived from the Greek word ‘tropia’, meaning the turning points.’ This year lasts 365.242199 days UT. 

The name topical years refer to the changes of seasons that remain fixed in this kind of year.

  1. Sidereal Year

A Sidereal Year lasts 365.256366 days UT. This year is the interval between two successive passages of the Mean Sun at the same star.

Lunar Calendar and Solar Calendar

A solar-lunar calendar carries a difference. Additionally, there is a feature that a lunar calendar upholds. 

So, let’s get started with the difference between the lunar calendar and solar calendar:

  • Lunar Calendar

Talking about a lunar calendar, we usually have 354 days; however, in a leap year, a lunar calendar has 384 days. 

  • Solar Calendar

A solar calendar has 365 days. In addition to it, there are 365 days, i.e.,  an additional day during a leap year.

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Additionally, a lunar calendar shifts quickly in contrast to a lunar calendar.

Give a List of Solar Calendars that are Used Currently or were Used in the Past

There are a number of examples of solar calendars available across the world. Some of these examples are the Assamese calendar, Astronomical year numbering, Assyrian calendar, Badi’ calendar, Bengali calendar, Basotho calendar, Berber calendar, Byzantine calendar, Bulgar calendar, Coptic calendar, Era Fascista, Discordian calendar, Ethiopian calendar, French Republic calendar, Florentine calendar, Gregorian calendar, Hanke-Henry Permanent Calendar, Holocene calendar, Indian national calendar, International Fixed Calendar, Invariable Calendar, Jalali calendar, Javanese calendar, Juche era calendar, Julian calendar, Malayalam calendar, Minguo calendar, Nanakshahi calendar, Odia calendar, Old Icelandic calendar, Pan Chronometer, Pataphysical calendar, Pax Calendar, Pentecontad calendar, Pisan calendar, Positivist calendar, Revised Julian calendar, Roman calendar, Runic calendar, Solar Hijri calendar, Soviet calendar, Swedish calendar, Symmetry454, Tamil calendar, Thai solar calendar, Tulu calendar, World Calendar, and World Season Calendar.

Do You Know?

An Islamic Calendar relies on the Lunar Calendar for ascertaining the dates of their festivals such as Ramadan and the pilgrimage to Mecca. 

Therefore, the lunar to Gregorian calendar advances through our Gregorian solar calendar by 11 days every year.

FAQs on Solar Calendar

1. Describe LuniSolar Calendar in Brief.

A calendar may be a calendar in many cultures whose date indicates both the Moon phase and therefore the time of the tropical year. 

If the solar year is defined as a tropical year, then a calendar gives a sign of the season. 

However, if it's taken us a year, then the calendar predicts the constellation near which the complete moon may occur. 

Likewise all calendars we divide the year into months there's a further requirement that the year has an entire number of months. 

In this case, ordinary years contain twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leaps month.

2. What is a Solar Cycle?

The solar cycle or solar magnetic activity cycle may be a nearly periodic 11-year change within the Sun's activity.

A solar cycle is measurable in terms of variations within the number of recorded sunspots on the solar surface. 

Wherefore, sunspots have been observed since the first 17th century, and therefore, the sunspot statistic is the longest continuously recorded statistic of any natural phenomena.

The magnetic flux of the Sun flips during each solar cycle.

Further, the sunspot cycle is near its maximum at the flip occurrence. 

Additionally, the levels of radiation, ejection of solar material, the quantity and the size of sunspots, solar flares, and coronal loops all possess a synchronized fluctuation.

These fluctuations may vary from active to dormant to active again, with a time period of 11 years.

3. What are the major differences between a solar calendar and a lunar calendar?

Solar calendar and lunar calendars are two different things and the major difference between these two types of calendars are:

  • The solar year is based on the movement of the sun while lunar calendars are made on the basis of the movement of the moon.

  • Solar calendars are more commonly used throughout the world compared to lunar calendars.

  • The length of a year is different in the solar calendars and the lunar calendars. The difference in time in both calendars is measured in terms of epact and one epact is equal to a difference of 11 days.

  • Lunar month refers to the time that the moon takes to pass through each of its phases, that is, new moon, half-moon, and full moon and then return back to its original position. A solar month is one-twelfth of the complete one revolution that the Earth takes around the sun.

  • There are 354 days in a lunar year whereas a solar year has 365 days. Therefore, after every 33 years, there will be a difference of one year between the solar calendars and the lunar calendars, that is, the lunar calendars will have an extra year in 33 years which will be formed because of the accumulation of extra days.

  • Solar calendars are considered all over the world, but Islamic calendars and Jewish calendars use lunar calendars. Chinese use a combination of both the lunar calendar and solar calendar. Thus, their calendar is known as a lunisolar calendar.

  • In every 3 years, one extra month is added to the solar years to adjust the increasing number of days while in solar calendars a leap day is added in the month of February every four years.

4. What are the different examples of Solar Calendars?

The most basic form of a solar calendar which was used in ancient times was the Julian calendar and the Coptic calendar. Both of these calendars are the same comprising 365 days in a year. An extra day was added every four years, making that year comprised 366 days. With time, the solar calendars evolved into two types and were made more accurate.

The first is the tropical solar calendars, wherein the position of the Earth in its orbit around the sun is analyzed with respect to the Equinox. The seasons are indicated by the dates on which the orbit crosses the equator. Examples of the tropical solar calendars are the ancient American calendar, Gregorian calendar, Bengali calendar, Iranian Calendar, and Indian National calendar.

The second is the sidereal solar calendars which indicate the zodiacal constellation near which the Sun can be found on the basis of the position of the Earth with respect to the fixed stars in the galaxy. Examples of sidereal calendars include the different forms of Indian calendars like the Hindu Calendar, Bengali calendar, Tamil calendar, and the Malayalam calendar.

The other form of the solar calendar is the Lunisolar calendar which includes an additional rule in order to keep synchronization between the solar year and the seasons. This type of calendar cannot indicate the position of the Earth on its revolution around the Sun.

The last is the non-solar calendars which are also known as the lunar calendars which are based on the movement of the Moon and not the Sun.

5. Which calendar is used by countries across the world?

Different countries have different modes of expressing their calendar based on their religion, for example, Afghanistan and Iran use the solar Hijri calendar, Bangladesh uses their Bangla calendar, Ethiopia uses its Ethiopian calendar, Indian National Calendar is used by the people of India, Israel uses Hebrew calendar. Apart from this, Japan has its own Japanese Calendar, the calendar used in Nepal is known as Vikram Samvat Calendar and that of Taiwan is known as the Minguo calendar, North Korea has the North Korea calendar and the calendars used in Thailand are known as the Thai Solar Calendar.