For the 135 film format (the most popular photographic film type), normal lenses are 50mm focal length. 35mm (with an angle of view of 63 degrees) and 28mm (75°) are slight wide-angle lenses.
24mm (84°), 20mm (94°), 17mm (104°) and 14mm (114°) offer more extreme views (for 35mm film).
This is different for digital photography. Many digital cameras use smaller sensors. This means that the focal lengths have an angle of view that is smaller. That way, an 18mm lens mounted on a digital camera of this type gives an angle of view of the 28mm wide-angle lens, namely 75 degrees, for a multiplier of 1.5.
One kind of wide-angle lens is a fish eye lens.
Telephoto lens is the opposite. It has a long focal length, and a narrow angle of view.
Grand Duchy of Hesse
The Grand Duchy of Hesse () was a former state that existed in modern-day Germany. It was formed in 1806 after the dissolution of the Holy Roman Empire as a result of the actions of Napoleon, who then elevated the former Landgraviate of Hesse-Darmstadt to the level of grand duchy. For this reason, this state was occasionally known simply as Hesse-Darmstadt.
Because Hesse-Darmstadt was a member of Napoleon's Confederation of the Rhine, it was forced to give up a considerable amount of territory at the 1815 Congress of Vienna. The territory of the Duchy of Westphalia, which Hesse-Darmstadt received from the 1803 "Reichsdeputationshauptschluss", was given to the Kingdom of Prussia. However, it received some territory on the western bank of the Rhine, including the important federal fortress at Mainz.
The Grand Duchy changed its name to the Grand Duchy of Hesse and by Rhine () in 1816.
The Grand Duchy of Hesse was divided into three provinces:
Puck (moon)
Puck is a closer moon to Uranus. Puck was found from the images taken by "Voyager 2" on December 30, 1985, and was given the designation S/1985 U 1.
In Celtic mythology and English folklore, a "Puck" is a mischievous sprite, imagined as an evil demon by Christians; the moon is named after the Puck who appears in Shakespeare's "A Midsummer Night's Dream", in which he travels around the globe at night with the fairies. It is also designated Uranus XV.
Puck is the biggest of the small closer moons to Uranus. It is in the middle in size between Portia and Miranda, the smallest of the five bigger moons. Puck's orbit is also located between these two moons. Little is known about it aside from its orbit, its radius about 81 km, and its geometric albedo approximately 0.11.
Of the moons found by the "Voyager 2" imaging team, only Puck was found early enough that the probe could be programmed to take pictures of it in some detail. Images showed that Puck has a shape of a slightly prolate spheroid (ratio between axises is 0.97 ± 0.04). Its surface is heavily cratered and is grey in color. There are three named craters on the surface of Puck. Observations with Hubble Space Telescope and large terrestrial telescopes found water ice absorption features in the spectrum of Puck.
Schinus
Schinus is a large genus of Anacardiaceae. They are commonly known as pepper trees. They prefer tropic subhumid zones.
Californian pepper tree "S.areira" native from Mexico to South America. Various species grown as ornamental, e.g. "S.areira", and Brazilian pepper "S.terebinthifolius".
Mab (moon)
Mab is a closer moon to the planet Uranus. It was found by Mark R. Showalter and Jack J. Lissauer in 2003 using the Hubble Space Telescope. It was named after Queen Mab, a fairy queen from English folklore who is noted in William Shakespeare's play "Romeo and Juliet".
Because the moon is small and dark, it was not seen in the images taken by "Voyager 2" during its Uranus flyby in 1986. However, it is brighter than another moon, Perdita, which was discovered from "Voyager's" photos in 1997. This led scientists to look at the old photos again, and the moon was finally found in the images.
If it is as dark as Puck, then it is about 24 km in diameter. On the other hand, if it is brightly coloured like the neighbouring moon Miranda, then it would be even smaller than Cupid and comparable to the smallest farther moons.
Mab is heavily perturbed, meaning its movement is not only caused by the gravity of another large thing. The actual source for perturbation is still unclear, but is probably one or more of the nearby orbiting moons.
Following its discovery, Mab was given the code name S/2003 U 1. The moon is also known as Uranus XXVI.
Telephoto lens
In photography, a telephoto lens is a lens. There are two different uses of the word. The less specific use is to mean a lens that has a longer focal length than a normal lens. Their angle of view is smaller than that of a normal lens. With telephoto lenses things look closer than they really are.
The other meaning of telephoto lens applies to lenses that are constructed in a special way so they can be shorter than their focal length.
For 35 mm film, 50 mm is a normal focal length. Typical telephoto lenses are 85 mm (28°50') and 100 mm (24°). They are used for portraits mostly. Other telephoto lenses that are used often are 135 mm (18°), 180 mm and 200 mm. Many are zoom lenses.
Longer focal lengths (300 to 1200 mm) are used in sports and nature photography.
Effect of different focal lengths on photographs taken from the same place:
The above photos were taken using a 35 mm camera, using lenses of the given focal lengths.
Umbriel (moon)
Umbriel is a moon of Uranus found on October 24, 1851 by William Lassell. It was found at the same time as Ariel.
The name "Umbriel" and the names of all four moons of Uranus then known were suggested by John Herschel in 1852 at the request of Lassell. Lassell had earlier supported Herschel's 1847 naming scheme for the seven then-known moons of Saturn and had named his newly-found eighth moon Hyperion in accordance with Herschel's naming scheme in 1848. Umbriel is the 'dusky melancholy sprite' in Alexander Pope's "The Rape of the Lock", and the name suggests the Latin "umbra", shadow. The adjectival form of the name is "Umbrielian".
It is also designated Uranus II.
So far the only close-up images of Umbriel are from the "Voyager 2" probe, which made observations of the moon during its Uranus flyby in January, 1986. During the flyby the southern hemisphere of the moon was pointed towards the Sun so only it was studied.
Umbriel's surface is the darkest of the Uranian moons, and reflects only about half as much light as Ariel, Uranus' brightest moon. It has far more and bigger craters than do Ariel and Titania and is also the least geologically active. It is mostly made of water ice, with the balance made up of silicate rock, and other ices such as methane. Methane can break down and form reddish-black organic compounds such as tholins when bombarded by high-energy particles. Near-IR spectra of Ariel and Umbriel clearly show that water ice dominates the spectra of these objects.
Craters on Umbriel are named after many different demons from various mythologies.
Titania (moon)
Titania is the biggest moon of Uranus and the eighth biggest moon in the Solar System.
Titania was found on January 11, 1787 by William Herschel. He reported it and Oberon the same year. He later reported four more moons, which turned out to be spurious.
The names of Titania and the other four moons of Uranus then known were suggested by Herschel's son John Herschel in 1852 at the request of William Lassell, who had found Ariel and Umbriel the year before. Lassell had earlier supported Herschel's 1847 naming scheme for the seven then-known moons of Saturn and had named his newly-found eighth moon Hyperion in accordance with Herschel's naming scheme in 1848.
All of the moons of Uranus are named for characters from Shakespeare or Alexander Pope. Titania was named after Titania, the Queen of the Faeries in "A Midsummer Night's Dream".