Details
A very rare French astrolabe,
signed PHILIPVS Danfrieus, and dated 1584, made of walnut, pasteboard and iron, with back, rete, and plates of paper printed from engraved copperplates, 86in. (21.4cm.) diameter, .11/16in. (1.8cm.) thick.
The instrument is made from a walnut board with the mater turned from the solid and with the throne integral. The mater is left as plain wood. The limb is printed from an engraved copperplate and is divided in single degrees alternately shaded, numbered by fives 0° to 90° in four quadrants. There is also an hour scale, twice XII hours. Part of this paper scale has been lost. The front and back of the throne have different Renaissance patterns in strapwork, and grotesque faces. The suspension is by shackle, swivel, and ring, swivel, all brass.
The rete is cut from pasteboard, with a strapwork pattern (part missing) carrying the flame pointers. The face has the remains of the engraved paper, and only nineteen star names can be distinguished out of the usual twenty-eight on Danfrie astrolabes.

Star List
NB: The missing star names are indicated by an asterisk (*); numerals are stellar magnitudes.

*CAVDA CETI 3
ANDROMEDA 3
VENTER CETI 3
CAP MED 3
DEX LAT PER -
OCVLVS TAURI 1
HIRCVS 1
SINISTER PES ORIO 1
DEX HVMERIS ORIONIS 1
CANIS MAIOR 1
CANIS MINOR 1
*LVCIDA HIDÆ 2
COR LEONIS 1
*ROSTRVM CORVI 3
CAVDA / -
PRIMA CAVDA VRSA MA 2
*SPICA VIRGINI 1
EXTRE CAV VR MA 2
ARCTVRVS 1
*PALMA OPHIVCHI 3
*COR SCORPII 2
*CAPVT OPHIVCHI 3
LIRA 1
*AQVILA -
CAVDA DELPHIN 3
CAVDA SIGNI 1
*CAVDA CAPRICOR 3
CRVS PEGASI 2

There are fives plates made of card with the projection on one side only, .11/16in. (1.8cm.) diameter.

I 42°
II 45°
III 48°
IV 51°
V 54°

The stereographic projection has azimuth at 5° intervals, and almucantars at 2° intervals. The tropics, equator, and crepuscular lines are engraved, as well as lines of unequal hours and the Houses of Heaven.
Both the alidade and the rule are made from cast iron. The arms are counterchanged, there is modest decoration at the centre, but there are no scales. The pin is a modern screw with a round head. The vanes on the alidade have broken off.

The back of the astrolabe has on the throne a grotesque face surrounded by scrolls. The circular scales, beginning from the outside, are: (1) 360° divided in four quadrants as on the front; (2) the degrees of each sign of the Zodiac followed by the pictorial representation, symbol, and name of each sign; (3) the days in each month; (4) the names of the months with vignettes, for example snow (December), tree pruning (March), flowers (May), cutting wheat (August). The calendar circle is eccentric with respect to the zodiac circle. The lower half of the central portion contains a shadow square with the edges graduated into twelve, with additional graduations to sixty labelled in fives. Underneath the square is the signature PHILIPVS Danfrieus, Siderographus Regius Generalis Lutetiæ exarabat, Anno Salutis 1584 *.
The upper portion contains two circles for calendars. The group is named Hoc Dorsum Kaldario reformato precise acmodatum est. The left-hand circle connects the Solar Cycle with the Dominical Letter, and the user is encouraged to use the reformed calendar by showing the position in the cycle of the years 1583, 1584, 1585, 1586. At the centre of the circle are the instructions Vsus haru duarõ Rotularum ab anno 1582 Vsque in ultimum diem futuri proxime Seculi duraturus est. The right-hand circle contains a table to find the date of Easter, connecting the Golden Number, Epact, and Easter date. The use is explained Die dominica p[ro]xime Sequenti Pascatis [sic] In dicem, qui est Luna decima quarta Primi mensis, sacrõ Pascha celebratr.
Literature
CHRISTIE'S SOUTH KENSINGTON, Exceptional Scientific and Engineering Works of Art, Instruments and Models, 8 April 1998 (London, 1998) Lot 50
DANFRIE, Philippe, Déclaration de l'usage du graphomètre (Paris, 1597)
DAUMUS, M., Les Instruments scientifiques aux XVIIe et XVIIIe Siècles (Paris, 1953) p.24
GIBBS, S., with SALIBA, G., Planispheric Astrolabes from the National Museum of American History (Washington D.C., 1984) pp.42-44, fig. 27, and pp.154-156, fig. 101.
GUNTHER, R.T., The Astrolabes of the World (Oxford, 1932) pp.358-9, no. 210
Tesseract: Early Scientific Instruments catalogue 41 (Hastings-on-Hudson, Summer 1993) item 6; both sides of throne on back cover.
TURNER, A.J., "Paper, Print and Mathematics: Philippe Danfrie and the making of Mathematical Instruments in late 16th Century Paris", in Studies in the History of Scientific Instruments (Papers presented to the 7th Symposium of the Scientific Instrument Commission, Paris, 1987), edited by Blondel, C., Parot, F., Turner, A.J., and Williams, M. (London and Paris, 1989) pp.22-42
WEBSTER, Roderick and Marjorie, Western Astrolabes (Historic Scientific Instruments of the Adler Planetarium, Volume 1) (Chicago, Illinois, 1998) pp.95-97, no. 19

Lot Essay

Philippe Danfrie (c.1532-1606) was born in Brittany, and moved to Paris in his twenties, where he became a partner in a printing and bookselling business. He designed a new typeface in cursive script, which was given the name 'civilité'. He later studied mathematics, bacame an 'ingénieur', and was appointed royal die cutter for coins of the realm. He is known for some twenty mathematical instruments, notably his astrolabes printed on paper, and for the invention of the graphomètre, on which he published in 1597 (A.J. Turner). His book was printed from copperplates engraved by himself, and the volume included a second tract on the use of the trigonomètre.
Of Danfrie's paper astrolabes, only six have been recorded until now. One, dated 1578, was described in Christie's catalogue 8 May 1998; another dated 1578 (IC 524), belongs to the Service Hydrographique de la Marine; the present one (1584) is advertised by Tesseract; another dated 1584 (IC210) belongs to the Museum of the History of Science, Oxford (Gunther); and another, dated 1584 but a printing from the 1620's (IC 2007), is at the National Museum of American History, Smithsonian Institute, Washington D.C. (Gibbs); and one of the same later period is at the Adler Planetarium and Astronomy Museum, Chicago (R. & M. Webster).
On this example, the first point of Aries is at 21 March. When the Gregorian calendar was introduced into Roman Catholic Europe in October 1582, Danfrie had to engrave a new copperplate for the back of his astrolabes with the first point of Aries at 21 March. When one compares the two editions of 1578 and 1584, it was only the back that had to be changed, and the front and the plates remain the same on the later edition. The 1584 back has a more grotesque face on the throne, all the months have improved vignettes, the shadow square is labelled both to 12 and to 60, and the upper central region is completely revised with just two perpetual calendar circles. For a description, see both Gunther and Gibbs. Another radical change is to a card rete; this has the same stars as on the brass rete. The alidade and rule on the 1584 astrolabe are not decorated, and the shackle is in plain brass.
The calendar change in 1582 is likely to have improved the market demand for inexpensive astrolabes, and a brass rete, even though it is more elegant and with sharper star pointers, would be expensive and time-consuming to produce. One may assume, then, that the price was less and that there was a good market.
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