The showcase is a separate “ecosystem” filled with items too old, special or fragile to be handled by untrained hands. This page features the current collection and hopefully is up to date. Some of the items are merely placeholders of little value, but in general look nice and interesting. All the items below are ordered by shelf with a description and the describing text (Dutch texts can be found in the discussion section.)

Text for in the showcase: Text

The top shelf features globes, both old and new. The centerpiece of the shelf is the large lunar globe in the center. This is an incomplete lunar globe.

Showcase description:
Alluding to great stature and wealth, the earliest globes, dating as far back as the Greek antiquity, more often served as artistic curiosities than as objects of study. It was not until the early 16th century that they began to be used as genuine cartographic instruments. As astronomical observation techniques improved, they were also increasingly used to depict the planets. Some examples of such globes can be seen here.

Dating from around 1960, this globe features the Moon from the side we all know it, but also parts of the side we don't. A large portion of the surface was filled in by the 1959 Russian “Luna 3” probe, which mapped parts of the far side of the Moon. All the newly discovered areas are shown with red letters, while the still unknown region remains empty. [(http://www.curatedobject.us/the_curated_object_/2013/11/exhibitions-chicago-mapping-the-moon-the-adler-planetarium-the-curated-object.html)] (Property of WLS)

The picture on the right shows the images sent back by the Luna 3 probe, upon which this globe is based.

Showcase description:
This globe showcases the surface area of the moon as discovered up until 1959. Since only one side of the moon is visible from Earth, large parts still hadn't been properly mapped by that time. Highlighted in red are several regions then recently explored by the Russian “luna 3” probe.

The second shelf is mainly dedicated to navigational instruments such as sextants, clocks and almanacs and imaging. These are old instruments and not understood by most, so you can read up on the history and use here. For a short discriptive text about using sextants and quadrants, please look here.

Showcase description:
Perhaps one of the greatest technical contributions of astronomy to human society is the invention of celestial navigation. Celestial navigation allowed sailors to accurately determine their location on Earth when traveling across the oceans. Displayed here are various nautical instruments that played a pivotal role in doing so.

This is a large nautical octant from the 18th century. This was among every seaman’s basic equipment. This octant is especially beautiful because of its ivory scales, something not at all unusual in those times. The arc is divided in 105 degrees and engraved with ‘F.W. Noor. Kjöbenhavn’, denoting the Danish manufacturers. Note the early form thumb screw stop, ivory vernier scale marked from 0 to 20 arc minutes, backsight, and triple sun shades indicative of manufactory soon after 1780. [(http://www.westsea.com/tsg3/octlocker/octcapchart10.html)]

Sextants like this were often used by seamen to determine their position. This was done by measuring the angle between the Sun and the horizon, and compare this to tabulated values in an almanac. Since this involved staring into the sun for long periods of time, this often blinded sailors! [(http://dispuutkaiser.nl/wiki/doku.php?id=telescopes:antique_sextant)]

Showcase description:
Created by the Danish manufacturers 'F.W. Noor. Kjöbenhavn' around 1780, this mahogany octant was used by seamen to accurately measure the angular separation between different celestial bodies. By using the instrument to determine the height at which the sun or another celestial body would pass through the local meridian (i.e. right overhead) and comparing with tabulated values one could establish one's local latitude.

A nautical almanac is a publication with tabulated values for the positions of a selection of celestial bodies. The almanac specifies for each whole hour of the year the position on the Earth’s surface (in declination and Greenwich hour angle) at which the Sun, Moon, planets and first point of Aries is directly overhead. The positions of 57 selected stars are specified relative to the first point of Aries.

To find the position of a ship or aircraft by celestial navigation, the navigator measures with a sextant the apparent height of a celestial body above the horizon, and notes the time from a marine chronometer. That height is compared with the height predicted for a trial position; the arcminutes of height difference is how many nautical miles the position line is from the trial position.[(http://en.wikipedia.org/wiki/Nautical_almanac)]

Showcase description:
Nautical Almanacs such as the one displayed here were used by sailors as comparison material, necessary for determining one's latitude. For each hour of the year this almanac lists the positions on Earth at which 57 selected stars, as well as the Sun, Moon and planets were directly overhead.

Showcase description:
Although seemingly mundane objects, clocks are vital instruments for enabling maritime navigation. On board of every ship one can find a so-called chronometer, a highly accurate clock that keeps track of the time of a predetermined location such as Greenwich. Comparison of the local time to the time at this location, allows one to calculate one's longitude.

A photometer measures the amount of light that hits it. It is in fact a one pixel camera. By putting one in a telescope the luminoscity of various objects can be determined. The large black one was used by Jan Hendrik Oort, discoverer of the Oortcloud and director of the observatory from 1945 to 1970. The glass tubes next to the photometer are photometric tubes, which can be seen as single analogue pixels.

Showcase description:
Former property of professor Jan Hendrik Oort, this photometer constituted a one pixel camera that could be used both for measuring the luminosity of various astronomical objects as well as for determining the correct exposures needed to create photographic images. Displayed next to the instrument are two glass photometric tubes, which can be seen as single analogue pixels.

These photos were taken with the Astrograph and a large telescope abroad. Taking pictures with this telescope could take many hours. The right picture shows the Andromeda galaxy with calibration spots in the corner, the left plate shows multiple images of Jupiter and its moons. Jupiter and its moons have been imaged multiple times to study the movement of the moons. The left plate was Oorts.

Showcase description:
Seemingly much more vulnerable than films, glass photographic plates remained one of astronomers' preferred image storage devices for much of the 20th century, owing to the fact that they didn't shrink or deformed noticeably during development or under environmental changes. On display here are two photographic plates, one depicting the famous Andromeda galaxy with calibration spots in the corner, the other showing multiple images of Jupiter that were used by professor Jan Hendrik Oort for studying the movement of its moons.

The third shelf shows the history of data storage.

Showcase description:
As a science of big data, astronomy brings forth many terabytes of information each single day. Not surprisingly, it's become increasingly important to find ways to efficiently catalog and save this information. The objects displayed here tell the history of digital data storage within astronomy.

This tape has been used heavily during the 1950's-1600's as means of input (there were no keyboards yet) and as means of storage. In the latter case these tapes could get very long and if they got dropped they unraveled. It is said that when this happened here, the astronomers would throw it out of the window on the first floor of the observatory and then manually roll it back up.

Showcase description:
One of the earliest forms of modern data storage, punched tapes were used extensively in the 1950s and 1960s not only to save data, but also as a means of input (the keyboard had yet to be invented). Notorious for their inconvenient shape, punched tapes would oftentimes reach astonishing lengths, proving to be a real pain when they were accidentally dropped and unraveled.

We have the three main generations of floppy disks here. The original 8 floppy, introduced in 1972 , would have 80 Kb of memory and the last edition would have 1.2 Mb. The 5¼ 'mini floppy' introduced in 78 would have similar capacities and the well known 3½'' disk appeared in the early 1980's with 1.44 Mb of storage. The last disk was very widely used until the early 2000's and is immortalized as the 'save icon' in many programs. Children these days will have no idea what it is and some even call it a print of the save icon.

Showcase description:
Displayed here are three subsequent generations of the floppy disk. A revolutionary new form of data storage, these devices first came in use in the 1970s and were able to store up to a few dozen kilobytes. Newer versions progressively decreased in size, resulting in the final 3 ½ inch version of the floppy disk, which was introduced in the early 1980s and was able to hold up to 1.44 megabytes of information. The device has been immortalized as the icon for the save button, now commonly found in many computer programs.

The left side of this shelf is dedicated to datatape. This was mainly used for storage of radio astronomy data, which was very big and hard to store in those days. The big tape on the right holds one picture for example. (Which is shown next to it.) This tape was soon overtaken by smaller datatapes and at some point even VHS tapes, which could hold a lot of data and were cheap.

Showcase description:
Some fields of astronomy produce greater amounts of data than others. This especially holds true for radio astronomy, which among other areas concerns itself with large extended objects that span vast regions of the celestial sky. The different data tape devices displayed here, including several cassettes and a video tape, were often employed by radio astronomers for storing images of their objects. An example of this is formed by the roll on the right, containing the image of radio sources depicted on the accompanying sheet of paper.

The bottom shelf has mostly calculation equipment.

Showcase description:
Tasked with charting the skies and exploring the unknown, astronomy has always involved doing a lot of calculations. The objects on display here proved invaluable aids in tackling the often painstaking amounts of work.

Before compact and cheap calculators were introduced around 1980 slide rules like these were used frequently, not only by scientists and engineers but also by high school students. The middle part can be slid with respect to the other parts, which could be utilized to perform multiplications, divisions and even logarithmes. These calculations were inaccurate in comparison to electric calculators, but they were very fast.

Showcase description:
Invented in the early 17th century, the slide rule grew to become one of most frequented calculation tools in history, being used regularly by both scientists, engineers and students alike up until the 1980s. Consisting out of three interlocked parallel strips, the central one of which can move relative tot the other two, the device allows one to quickly perform multiplications, divisions and even more complex calculations like logarithms.

The first calculator was built in 1623, but they weren’t sold commercially until 1887. This model comes from a company called Original Odhner and was produced from 1935 to 1945. It uses pinwheels and can add or subtract 10 digit numbers by setting the number and turning the handle. By repeatedly adding or subtracting the same number it can also be used to perform multiplications and divisions. (Property of Alex)

Showcase description:
Although they had existed since the early 17th century, mechanical calculators did not come into general use until after 1887. On display here is a model fabricated by a company called Original Odhner between 1935 and 1945. Exploiting a system of pinwheels, the device is able to add and subtract 10 digit numbers by setting a value and turning the handle. Multiplications and divisions can be carried out by repeatedly adding or subtracting the same number.

This is the Monromatic 8N-213, an electric calculator from 1960. The electric calculator was invented in 1954 as the succesor to the mechanical calculator. It can add, subtract, multiply and divide. It even differentiates between positive and negative numbers. Each column on the keyboard represents a digit.

Showcase description: Designated to become the widespread successor of the earlier mechanical calculator, the first electrical calculators appeared in 1954. This Monromatic 8N-213 model, originating from 1960, allows one to quickly add, subtract, multiply and divide, even differentiating between positive and negative numbers. Note how the columns on the keyboard each represent a single digit.

[]These cards are punched cards. In the twentieth century they were widely used in the computer industry. They were used to enter commands, as is the case with these cards. Each command had it's own specific combination of holes.

Showcase description:
Widely used by both scientists and engineers, these punched cards formed one of the backbones of computing systems throughout much of the twentieth century. One of their main purposes was providing for a means of entering commands: a separate command was denoted by each specific combination of holes. When computer programs were created using a set of punched cards, people had to be very careful not to accidentally disarrange them, for the program would become dysfunctional if the cards weren't ordered the right way.