A solar calendar is a calendar whose dates indicate the position of the earth on its revolution around the sun (or equivalently the apparent position of the sun moving on the celestial sphere).

If the position of the earth in its orbit around the sun is reckoned with respect to the equinox, the point at which the orbit crosses the celestial equator, then its dates accurately indicate the seasons, that is, they are synchronized with the declination of the sun. Such a calendar is called a tropical solar calendar.

The duration of the mean calendar year of such a calendar approximates some form of the tropical year, usually either the mean tropical year or the vernal equinox year.

The following are tropical solar calendars:

Every one of these calendars has a year of 365 days, which is occasionally extended by adding an extra day to form a leap year, a method called "intercalation", the inserted day being "intercalary".

The Zoroastrian calendar is a religious calendar used by adherents of the Zoroastrian faith, and is an approximation of the tropical solar calendar.

Angus MacLise (March 4, 1938, Bridgeport, Connecticut – June 21, 1979, Kathmandu, Nepal) was an American percussionist, composer, poet, occultist and calligrapher probably best known as the first drummer for the Velvet Underground.

MacLise was a member of La Monte Young's Theater of Eternal Music, with John Cale, Tony Conrad, Marian Zazeela and sometimes Terry Riley. He contributed to the early Fluxus newspaper VTre, edited by George Brecht, and was also an early member of The Velvet Underground, having been brought into the group by flatmate John Cale when they were living at 56 Ludlow Street in Manhattan.

MacLise played bongos and hand drums during 1965 with the first incarnation of the Velvet Underground. Although the Velvets regularly extemporised soundtracks to underground films during this era, MacLise never officially recorded with them, and is often considered something of a shadowy, legendary figure in their history. When the opportunity of the band's first paying gig in November 1965 arose, MacLise promptly quit, suggesting the group were selling out.

Abadin Tadia Tjoessoep (1626–1699), more commonly known as Sheikh Yusuf, was an Indonesian muslim of noble descent. In 1693 he was exiled to the Cape of Good Hope which resulted in his establishing Islam in the Cape.

Yusuf was born in Makassar, Indonesia, the nephew of King Biset of Gowa. In 1644 he embarked on the Hajj to Mecca and spent several years in Arabia learning under various pious scholars. During this period the Dutch and British East India Companies were fighting for control of the region due to its lucrative trade in spices and gold. When Yusuf left Arabia in 1664, Makassar had been captured by the Dutch, and he was unable to return home. Instead, he headed for Bantam on the island of Java, where he was welcomed by Sultan Ageng Tirtayasa. Ageng gave Yusuf the hand of one of his daughters in marriage, and made him his chief religious judge and personal advisor. Yusuf stayed in Bantam for 16 years until 1680, when Ageng's son, Pangeran Hajji, rose against his father, possibly at the urgings of the Dutch East India Company. Ageng rallied his forces, including Yusuf, and in 1683 besieged Hajji in his fortress at Soerdesoeang. Ageng was defeated but managed to escape capture, along with an entourage of about 5,000, among them the 57-year-old Yusuf. Ageng was captured later that year but Yusuf managed to escape a second time and continued the resistance.

Yusuf Estes (born in 1944) is an American Muslim preacher and teacher who converted from Christianity to Islam in 1991. He was a Muslim Chaplain for the United States Bureau of Prisons through the 1990s. He was a Muslim Delegate to the United Nations World Peace Conference for Religious Leaders held at the U.N. in September 2000.

Active in Islamic missionary work in the United States, Estes is often featured as guest presenter and keynote speaker at various Islamic events as well as frequently appearing on various Islamic satellite TV channels. Estes takes a dim view of today's public school system in the United States for any children, and highly recommends schools where they might receive a religious education combined with more advanced scholastic education.

Yusuf Estes was born in Ohio, and was raised in Houston, Texas in a Anglo-Saxon Protestant family. From 1962 to 1990, his career was in the music, entertainment and marketing fields. He also taught music and served as a music minister. He owned several musical instrument companies including the Estes Piano and Organ Company. He produced and directed live entertainment programs in the United States from the mid 1960s until his last endeavor for cable TV in Florida, entitled 'Estes Music Jamboree'.