“The first major writer on the projection was the famous Claudius Ptolemy (ca. AD 150) who wrote extensively on it in his work known as the Planisphaerium. There are tantalizing hints in Ptolemy’s writing that he may have had an instrument that could justifiably be called an astrolabe. Ptolemy also refined the fundamental geometry of the Earth-Sun system that is used to design astrolabes.
“Early Astrolabes “No one knows exactly when the stereographic projection was actually turned into the instrument we know today as the astrolabe. Theon of Alexandria (ca. 390) wrote a treatise on the astrolabe that was the basis for much that was written on the subject in the Middle Ages.
“Synesius of Cyrene (378-430) apparently had an instrument constructed that was arguably a form of astrolabe. This is plausible since Synesius was a student of Hypatia, Theon’s daughter. The earliest descriptions of actual instruments were written by John Philoponos of Alexandria (a.k.a. Joannes Grammaticus) in the sixth century and a century later by Severus Sebokht, Bishop of Kenneserin, Syria, although it is likely that Sebokht’s work was derivative of Theon. It is certain that true astrolabes existed by the seventh century.”
Source: astrolabes.org [kadrey remarks: This page was constructed and written by James E. Morrison, who teaches an Introduction to Astronomy course at Montgomery College at Tokoma Park in Connecticut. If you’re really interested in astrolabes, he sells cool, working models through the site.]
the Astrolabe in Islam
From Richard Kadrey
“The Astrolabe in Islam “The astrolabe was introduced to the Islamic world (Istanbul Observatory) in the eighth and ninth centuries through translations of Greek texts. The astrolabe was fully developed during the early centuries of Islam. Arab treatises on the astrolabe were published in the ninth century and indicate a long familiarity with the instrument (the oldest existing instruments are Arabic from the tenth century, and there are nearly 40 instruments from the 11th and 12th centuries).
“The astrolabe was inherently valuable in Islam because of its ability to determine the time of day and, therefore, prayer times and as an aid in finding the direction to Mecca. It must also be noted that astrology was a deeply imbedded element of early Islamic culture and that astrology was one of the principle uses of the astrolabe. .
“Persian astrolabes became quite complex, and some were genuine works of art. There are a number of interesting stylistic differences between astrolabes from the eastern Islamic areas (the Mashriq), Northern Africa (the Maghrib) and Moorish Spain (Andalusia). The astrolabe was also used in Moslem India in a simplified and less artistic form.”
Source: astrolabes.org [kadrey remarks: This page was constructed and written by James E. Morrison, who teaches an Introduction to Astronomy course at Montgomery College at Tokoma Park in Connecticut. If you’re really interested in astrolabes, he sells cool, working models through the site.]
the Astrolabe in Europe
From Richard Kadrey
“The Astrolabe in Europe “The astrolabe moved with Islam through North Africa into Spain (Andalusia) where it was introduced to European culture through Christian monasteries in northern Spain.
“It is likely that information about the astrolabe was available in Europe as early as the 11th century, but European usage was not widespread until the 13th and 14th centuries. The earliest astrolabes used in Europe were imported from Moslem Spain with Latin words engraved alongside the original Arabic. It is likely that European use of Arabic star names was influenced by these imported astrolabes.
“By the end of the 12th century there were at least a half dozen competent astrolabe treatises in Latin, and there were hundreds available only a century later. European makers extended the plate engravings to include astrological information and adapted the various timekeeping variations used in that era. Features related to Islamic ritual prayers were generally discarded in European instruments.
“The astrolabe was widely used in Europe in the late Middle Ages and Renaissance, peaking in popularity in the 15th and 16th centuries, and was one of the basic astronomical education tools. A knowledge of astronomy was considered to be fundamental in education, and skill in the use of the astrolabe was a sign of proper breeding and education. Their primary use was, however, astrological.
“Geoffrey Chaucer thought it was important for his son to understand how to use an astrolabe, and his 1391 treatise on the astrolabe demonstrates a high level of astronomical knowledge.
“Astrolabe manufacturing was centered in Augsburg and Nuremberg in Germany in the fifteenth century, with some production in France. In the sixteenth century, the best instruments came from Louvain in Belgium.
“By the middle of the seventeenth century astrolabes were made all over Europe. A particularly interesting workshop was founded by Georg Hartmann in Nuremberg in about 1525. It is clear that Hartmann used an early form of mass production to produce his high quality instruments. It is very likely that most workshops acquired parts of finished instruments from specialists, or other shops were employed for services such as gilding.
“Brass astrolabes were quite expensive, and only the wealthy could afford a good one. Paper astrolabes became available as printing developed, and many were surely made, although few survive.
“Several interesting astrolabe variations to make a single instrument usable in all latitudes were invented in the 15th and 16th centuries, but due to their high cost and complex operation, never gained the popularity of the planispheric type.”
Source: astrolabes.org [kadrey remarks: This page was constructed and written by James E. Morrison, who teaches an Introduction to Astronomy course at Montgomery College at Tokoma Park in Connecticut. If you’re really interested in astrolabes, he sells cool, working models through the site.]
Chaucer’s Astrolabe Manual
From Richard Kadrey
[Bruce Sterling remarks: It’s a pleasure to welcome noted poet and diplomat Geoffrey Chaucer (appr. 1340-1400) back to the Dead Media Project. The following contains selected highlights from Chaucer’s treatise on the astrolabe, originally some 14,811 Middle-English words. This document is said to be the earliest known “technical manual” in the English language. It was originally written for a child of ten, “lyte Lowes” or ‘little Lewis,’ who is thought to have been the son of a friend of Chaucer’s. Sadly, the boy succumbed to the high child- mortality rates of the plague-ridden 14th century, and Chaucer’s tech manual was never completed. Personally, I find this document well-nigh unreadable. Keep in mind, however, that this is probably a “Big Dummies’ Guide to the Astrolabe,” since it was once considered proper reading for a child of ten. This may be as close as we can get to imagining what a Windows 95 software manual might look like to people six hundred years from today]
A TREATISE ON THE ASTROLABE
by Geoffrey Chaucer, appr. 1391
“Lyte Lowys my sone, I aperceyve wel by certeyne evydences thyn abilite to lerne sciences touching nombres and proporciouns; and as wel considre I thy besy praier in special to lerne the tretys of the Astrelabie. by mediacioun of this litel tretys, I purpose to teche the a certein nombre of conclusions aperteynyng to the same instrument.
“I seie a certein of conclusions, for thre causes. The first cause is this: truste wel that alle the conclusions that han be founde, or ellys possibly might be founde in so noble an instrument as is an Astrelabie ben unknowe parfitly to eny mortal man in this regioun, as I suppose. An-other cause is this, that sothly in any tretis of the Astrelabie that I have seyn there be somme conclusions that wol not in alle thinges parformen her bihestes; and somme of hem ben to harde to thy tendir age of ten yeer to conceyve.
“This tretis, divided in 5 parties, wol I shewe the under full light reules and naked wordes in Englissh, for Latyn ne canst thou yit but small, my litel sone. “Now wol I preie mekely every discret persone that redith or herith this litel tretys to have my rude endityng for excusid, and my superfluite of wordes, for two causes. The f
irst cause is for that curious endityng and hard sentence is ful hevy at onys for such a child to lerne. And the secunde cause is this, that sothly me semith better to writen unto a child twyes a god sentence, than he forgete it onys.
“And Lowys, yf so be that I shewe the in my light Englissh as trewe conclusions touching this mater, and not oonly as trewe but as many and as subtile conclusiouns, as ben shewid in Latyn in eny commune tretys of the Astrelabie, konne me the more thank. And preie God save the king, that is lord of this langage, and alle that him feith berith and obeieth, everich in his degre, the more and the lasse. But considre wel that I ne usurpe not to have founden this werk of my labour or of myn engyn. I n’am but a lewd compilator of the labour of olde astrologiens, and have it translatid in myn Englissh oonly for thy doctrine. And with this swerd shal I sleen envie. “PART I “Here begynneth the descripcioun of thin Astralabie.
“1. Thyn Astrolabie hath a ring to putten on the thombe of thi right hond in taking the height of thinges. And tak kep, for from henes forthward I wol clepen the heighte of any thing that is taken by the rewle “the altitude,” withoute moo wordes.
“2. This ryng renneth in a maner toret fast to the moder of thyn Astrelabie in so rowm a space that it distourbith not the instrument to hangen after his right centre.
“3. The moder of thin Astrelabye is thikkest plate, perced with a large hool, that resceiveth in hir wombe the thynne plates compowned for diverse clymates, and thy reet shapen in manere of a nett or of a webbe of a loppe.”. “6. Tlle est syde of thyn Astrolabie is clepid the right syde, and the west syde is clepid the left syde. Forget not thys, litel Lowys.”. PART II “1. To fynde the degre in which the sonne is day byday, after his cours aboute.
“Rekne and knowe which is the day of thy month, and ley thy rewle up that same day, and than wol the verrey poynt of thy rewle sitten in the bordure upon the degre of thy sonne.
“Ensample as thus: -The yeer of oure Lord 1391, the 12 day of March at midday, I wolde knowe the degre of the sonne. I soughte in the bakhalf of myn Astrelabie and fond the cercle of the daies, lo the whiche I knowe by the names of the monthes writen under the same cercle. Tho leyde I my reule over this forseide day, and fond the point of my reule in the bordure upon the firste degre of Aries, a litel within the degre. And thus knowe I this conclusioun.”.
VISIDEP 3-D Television
From Stefan Jones
“3-D TV is here
“Scientists generally believe that our ability to perceive depth is the result of our binocular vision. Now, challenging this concept, three University of Southern Carolina scientists have developed a technique that makes 3-D television, movies and slides a reality for everyone, even those with poor vision or vision in only one eye.
“No special glasses, cameras, projectors or television sets are needed. And unlike traditional 3-D, the Visual Image Depth Enhancement Process (VISIDEP) produces images which have realistic depth and fullness, rather than exaggerated images which seem to leap outward.
“Drs. Edwin Jones, LeConte Cathey and Porter McLaurin, experts in optics, electronics and media production, respectively, developed their novel approach by observing how a visually impaired person perceives depth. ‘We discovered that a one-eyed person perceives depth by moving his head and comparing a sequence of visual ‘frames’ from different angles,’ Dr. Cathey told PM. This concept was once considered impossible by physiologists.
“VISIDEP simulates the optics of a one-eyed person by using conventional video equipment, plus a special encoding device which produces a time-sequence display of images captured from two different points of view on a single channel.
[ The “shuttered glasses” 3-D technique also uses alternating frames; the shutters alternately black out the right and left lenses, limiting vision in a particular eye to the appropriate frames. VISIDEP seems to rely on the human eye’s ability to fuse rapidly presented images. although how this produces a 3-D effect is not explained.]
“Variations on the technique allow the South Carolina team to create 3-D images from slides, motion pictures, and computers. [The article at this point includes a photographic stereo pair depicting the three researchers. The caption implies (“You can simulate the new 3-D effect.”) that it is produced by the VISIDEP effect, but it seems to simply be a high-quality stereo pair.]
[ Description of the “red - green” 3-D technique, and its drawbacks, deleted.] “VISIDEP has none of these restrictions. Once encoded, the image may be reproduced by any single conventional video camera [sic], movie, or slide projector. [ I believe the author meant to write ‘video monitor.’ ] The depth moves into the screen rather than out toward the audience, making the image more lifelike.
“Since VISIDEP can be applied to images generated by virtually any means, including X-rays, sonar, infrared or visible light, as well as from fiber optics, potential applications range from undersea and satellite transmission [ ?!!? -- SEJ ] to medical and computer sciences.
“Once particularly exciting application involves VISIDEP’s ability to produce three-dimensional computer- aided design and manufacturing [sic]. With VISIDEP it’s possible to display these images in three dimensions.
“For nontechnical applications, the most immediate use of VISIDEP probably will be for televising commercials and sports events.
“VISIDEP may also have an effect on some long- standing theories of perception.
“As Jones stresses, ‘Our development will force people to take another look at standard theories of how people perceive depth, and, thus, how all of us learn.’” [ Whither VISIDEP? Like the dinosaurs, or the strange critters of the Cambrian epoch, the system may have failed to catch on through no fault of its own. Lost research grants, patent problems, a lack of investors, or inept marketing could have scuttled the system at any of the stages necessary to make a clever idea into a product. Of course, the system may have simply failed to impress, or even worse, caused headaches and eye strain, like so many other 3-D systems.]
Source POPULAR MECHANICS Technology Update, March 1983, Page 129
Coins as Media
From Joel Altman
“Coins have been a major force in helping to advance civilization.. In ancient times, they spread the news of major construction projects, changes in political leadership, and other important events. They have served as mini-newspapers, objects of art, and even sources of propaganda.” Commemorative coins informed the world of significant events, accessions, or conquests. Ancient rulers, like today’s, wanted to be in the news much as possible, so they put their names and images on their coinage. The person who first decided to put news on coinage was a genius of the first water, for he solved the problems of news creation, distribution, and archiving in one fell swoop.
Source Coins as Living History by Ted Schwarz ARCO Publishing Co., New York, 1976.
Interactive Cable Television: Cableshop
From Stefan Jones
“While major cable TV interests are entering what experts believe is a shakeout period, small-scale experiments in ‘interactive’ cable are demonstrating what the future may bring.
“In Peabody, Mass., a collaboration between the local cable distributor and J. Walter Thompson, the large advertising agency, has produced something called Cableshop. From a ‘menu channel,’ subscribers select from a number of short subjects of special interest. Almost all of them are supplied or underwritten by companies with related products. For instance, food companies might support recipe shows or Kodak might sponsor a picture- taking clinic.
“The subscriber dials an access number, identifies himself to the Cableshop computer with his individual code, and dials the number of the presentation he wants to see. Then, a message guide channel indicates the time his message is scheduled and the channel on which it can be seen. If a program is already scheduled to do another request, that information is relayed as well.
“According to Peabody lore, a man waiting for his wife to finish dressing for dinner
dialed up a Ford Escort film recently and was so impressed that he went out and bought one.” [ I pity this man’s wife come the advent of the Home Shopping Channel.] “Meanwhile, in the high-income community of Ridgewood, N.J., an interactive test will supply 500 families with free computer keyboards.”
Source: POPULAR MECHANICS January 1983 Technology Update column
a personal recollection of VisiDep 3-D Television
From Rick Gregory
I knew Porter McLaurin very well while the troika were developing VisiDep. He was chairman of the Media Arts Department at USC (University of South Carolina) and my graduate advisor when I was a grad student there. I crewed on several VisiDep shoots. I was kind of surprised when Popular Mechanics picked up the news release in 1983 and repeated it almost verbatim. McLaurin, Cathey and Jones always saw more in VisiDep than anyone else. What I saw was an unstable, switched video image that was more disorienting than anything else. The video rig used to shoot it looked like a deformed moose with two cameras on a jerry rigged quadra pod. I thought then, and still believe, that the PM reporter had to make a deadline and never came close to actually seeing the VisiDep reality. He jazzed up a university Public Information Department news release and never looked at the technology. Kinda makes me wonder how much we can trust some other reports of technology from the popular/scientific media.
Source: Personal Experience
Anschutz’s arcade peepshow
From Stephen Herbert
The Dead Media Notebook Page 38