Post on 18-Oct-2020
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Astrolabe.
Expert report by S. Maslikov, Cand.Sc. Physics and Mathematics.
Private collection, Moscow.
Provenance: purchased at an Austrian art auction house about 20 years ago.
An astrolabe consists of a mater, spider, 4 plates, alidade, axle, pin in a form of a curved dagger,
suspension with a ring and a cord. Total weight: 342 gr.
A brazen body is 92 mm in diameter and 7 mm thick.
The throne on the front side is decorated with a flower with 9 large petals resembling a sunflower;
below there are two more flowers with stems and leaves. The background is treated with a square-
headed punch. The back side of the throne is decorated with interweaving floral design – stems
and leaves, with rounded grain-shaped punch marks on the background.
Front and back side of the throne.
The limb on the FRONT is divided into 360 degree divisions. Every five degrees are grouped and
signed by the Abjad system, i.e. the numbers are in Arabic letters. The counting starts from the
horizontal diameter on the right and left and goes up and down to the vertical diameter. That
means that all four quadrants are signed with numbers from 5 to 90 degrees. This method of
marking refers to the end of the 18th - early 19th centuries. This scale was used in conjunction
with the spider pointer (a dash at the top of the spider) to measure the position of the vernal
equinox relative to the zenith. It is quite rare. Thus, in the vast collection of the National Museum
of American History (Washington), there are only four such instruments - №№ 58, 61, 62, 66
(Gibbs, Saliba, p. 25) of 48 astrolabes available.
GAZETTEER. On the bottom of the mater in two circles, there is a table of coordinates of 38
geographical points (23 in the outer circle and 15 in the inner circle). The header column (the first
column to the left of the vertical diameter) contains the name of [city] دالبلا - bilad, longitude لوط
- aṭwāl, latitude ضرع - curūḍ, and qibla فارحنا - inḥirāf.
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Numerical values are given by the Abjad system in degrees and minutes of arc. Zero is indicated
by a small circle.1 City names follow counterclockwise (see Table 1). In the center of the gazetteer
in four quadrants the four intercardinal directions are engraved (starting from the upper left
quadrant counterclockwise). They have a purely decorative function:
Southeast sarqi ganubi شرق جنوب,
Northeast sarqi samali شرق شمال,
Northwest gharbi ganubi غرب جنوب,
Southwest gharbi samali غرب شمال.
Table 1 – Gazetteer.
№ Name (city) Arabic script Longitude Latitude Qibla Notes
Outer circle
1 Baghdad 33 80 بغداد ? ?
2 Tabriz تبريز
82 38 15 30 The same as Qibla №15
(Gibbs)
3 Marāgheh 30 15 20 37 82 مراغه Qibla is incorrect
4 Ardabil 15 38 20 82 اردبيل ? Qibla is incorrect
5 Shahrazur 35 35 35 35 20 82 شهرزور
6 Abadan بادان Rarely found 30 25 20 30 84 ع
7 Qazwīn قزوين
85 36 27 30 The same as Qibla №15
(Gibbs)
8 Qum قم 85 30 35 40 32 ?
9 Sāwa (Saveh) 14 29 35 85 ساوه
10 Kāshān قاشان
86 34 45 36 8 The same as Qibla №15
(Gibbs)
11 Iṣfahān 40 40 25 32 40 86 اصفهان
12 Yazd يزد
89 30 ? 47 17 The same as Qibla №15
(Gibbs)
13 Shīraz زسيرا 88 29 ? 31 ?
هاركشبا ? 14 89 33 33 ? 33
15 Kirman 63 40 30 30 92 كرمان
16 Neyšâbur نيشابور 92 30 36 27 46
17 Tus سطو 92 30 37 45 35
18 Herāt 30 34 20 94 هرات ?
19 Marw 40 37 ? 97 مرو ?
20 Bukhara 47 ? 39 30 97 بخارا?
21 Samarqand
سمرقند
98 40 49 All three coordinates are
the same as on №15
(Gibbs). Typical values are
99, 39, and 14.
22 Balkh 30 35 41 37 101 بلح
23 Khujand حجند
100 25 41 56 ? Longitude 100 has №86
(Gibbs)
Inner circle
24 Dimashq 30 33 40 70 دمشق ?
25 Bayt al-maqdis المقادس بيت 60 ? 30 20 20 Qibla is incorrect
26 Miṣr 30 67 20 30 63 مصر Qibla is incorrect
1 Such a designation of zero is not generally accepted and may provide additional information.
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27 Rahbeh ? 6 ?46 ? 34 ? 74 يهند? Qibla is incorrect
?48 30 34 33 هدنه ? 28
29 Jiddah ? 31 76 ودن ?
30 Habash ? 40 44 ? ? حبشه Qibla is incorrect
31 ? 84? 10 44 44
32 ? 86 37? 69 30
33 Hurmūz
(Ormuz) هرموز
92 30 ? 45
34 Thanah 69 20 29 102 تانه
35 Sistan ثانسس 97 32 30 36 4
36 Kashmir شمرك 105 35 40 60 7
37 Multan 4 71 40 29 35 107 ملتن
هكدبم ? 38 86 30 29 37? 77 13?
An analysis of the table revealed some interesting features: several azimuths of qibla accurately
repeat the astrolabe №15 from the Washington catalogue [Gibbs, Saliba, pp. 64-65]. This indicates
the possible roots of this astrolabe, as well as the astrolabes from the Museum of the East
(Moscow) - the Persian city of Kerman. More specifically, this fact is a clear indication of the
traditions of the masters of the city of Kerman.
Most of the cities are identified; their coordinates correspond to generally accepted values in the
past. This clearly indicates the authenticity of the instrument. The estimated time of creation of the
gazetteer is the end of the 18th - beginning of the 19th century.
SPIDER: diameter is 75 mm. It contains pointers of 26 stars (see Table 2). Symmetrically located
pointers of stars №23 (Alpha Cygni) and №17 (alpha of the Northern Crown) are made in the
form of bird heads. Vega is usually depicted this way (Alpha Lyra, №20). There is a handle for
rotating the spider, located to the right in the area of the Spica star (№ 15). Some inscriptions are
difficult to read as if they were made by another hand.
Table 2 – Astrolabe Stars.
№ Name in
Arabic script Transliteration English translation
Identifi-
cation
الحوت بطن 1 baṭn al-ḥūt the belly of the fish β And*
fam al-qayṭus the mouth of Cetus γ Cet فم القيطس 2
ghūl [the head of] the Demon β Per غول 3
عيوق 4cayyūq (?) α Aur
α Tau ? درر 5
rijl the left foot β Ori رجل 6
? ? رني 7
مانيي 8 yamānῑyyah the southern Sirius α CMa
α UMa ? ال 9
sha’āmῑ[yyah] the northern Sirius α CMi شامي 10
fard the solitary one of the water snake α Hya فرد 11
qalb al-asad the lion’s heart α Leo قلب األسد 12
13 ? γ Crv
al-canāq the badger (a desert animal) ζ UMa العناق 14
عزلالا 15 al-aczal the unarmed simāk α Vir
16 ? α Boo
ةالفك 17 al-fakka the bright one of the broken vessel α CrB
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al-ḥawwā’ head of the snake-charmer α Oph الحوا 18
-qalb al قلب العقرب 19caqrab the scorpion’s heart α Sco
20 ? α Lyr
ṭā’ir the flying eagle α Aql اطائر 21
dhanab al-jadī the tail of the goat δ Cap ذنب الجدي 22
al-dajāja the bird’s head α Cyg ? الدجاجة 23
24 ? β Peg
al-khāḍῑb the stained hand β Cas الخضيب 25
26 ذنب قيطس
dhanab qayṭus
[janūbῑ]
the southern tail of Cetus β Cet
* β And - the only one star that is out of place. It must be inside the circle of the ecliptic.
The inscriptions marked with a question mark are illegible, although it is clear what the stars
should be there.
One star is incomprehensible - №7 - between the beta of Orion and Sirius.
Most of the stars are identified, placed and signed correctly. The spider made by the hand of an
experienced master and, most likely, can be dated, like other elements, back to the end of the 18th
- the beginning of the 19th century.
PLATES: 4 pcs. The fixation slot locates underneath. Just below the middle line of the plate, there
are two ornately shaped cartouches with inscriptions: on the right- the latitude (curūḍ - htiw (عرض
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a corresponding value, on the left - the duration of the longest day (sācātuhu - ehT .(ه ساعات
daytime length is indicated under the cartouche in hours and minutes.
Fragment of the plate 2b with inscriptions.
Plate parameters:
1a - 32º (14 h. 07 min.);
1b - 34º (14 h. 18 min.);
2a - 34º (14 h. 18 min.) – similar to side 1b;
2b - 36º (14 h. 30 min.) - next to the digit 14, digit 13 was, possibly, mistakenly inscribed, the
digit 30 is rotated at the right angle (see fig.);
3a - 38º (14 h. 40 min.);
3b - 40º (14 h. 52 min.);
4a - 22º (13 h. 21 min.) - for the latitude of Mecca (21º40 ');
4b - horizon lines for all latitudes, grouped in four sectors.
The degrees of latitudes on the plate correctly correspond to the maximum daylight length.
On each plate, there are all principle circles: the tropics of Cancer and Capricorn, the equator,
as well as the vertical diameter (meridian), and the horizontal diameter (straight horizon).
Circles of equal heights (Almucantarats) drawn in increments of 6º. The circles from 6 to 90 are
signed in the Abjad system. The inscriptions are duplicated by Indo-Arabic numerals
١٢٣٤٥٦٧٨٩, which is typical of astrolabes from Lahore. Equal azimuth lines are drawn and
signed below the horizon in increments of 10º. The numbering goes from east and west points
to the central meridian. The exception is the prime vertical, i.e. azimuth 0º, which is drawn
above the horizon. Hours are indicated by dotted lines and signed in the Abjad system. The
sides of the horizon are signed - east (Al-Mashriq قرشملا) on the left and west (Al-Maghrib
.thgir eht no (غرب م ال
Plate1a. 32 degrees latitude. The intersection points of the principle line shown in white circles - a characteristic
sign of the high quality of the plate manufacturing. The accuracy on other plates is slightly worse.
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The horizon plate also contains lines for polar latitudes - 66º30 ', 78º, 84º. The astrolabe from the
Museum of the East in Moscow has the same lines (with more complete information) [Maslikov,
Sarma, 2016].
The high precision of plate manufacturing is especially well seen at the intersection points of four
principle lines, one of which is a straight line - the straight horizon, and three radial arcs - the
inclined horizon, the prime vertical and the equator (in the figure, these two intersection points are
indicated by white circles). This proofs that the master performed his work with skill. However,
this is indicated by other elements as well, for example, the correct position of circles of equal
height.
BACK. The limb is divided into degree divisions; every 5th degree is signed. The counting goes
from the horizontal diameter up and down, in the same way as on the Front of the astrolabe. The
design of the scales is also identical.
In the upper left quadrant - the scale of the sines. In fact, there are two scales; the smaller one is
embedded in the larger one. The outer scale has the horizontal lines drawn per 5 degrees; they are
concentrated in the upper part. The inner scale has radial lines and concentric arcs. Both those and
others are indented in increments of 5 units, the arcs are signed from the center to the outer edge:
5, 10, 15 ... 60. The purpose of this scale is to solve the equations of the form sin A = sin B / sin C
[Morrison, p. 130]. The scale of the sines is made with low accuracy and less neat, which is in
discord with other elements of the astrolabe as if the master entrusted its manufacture to his
inexperienced apprentice.
In the upper right quadrant half of the shadow square is placed, inside of which is a table of
triplicities. Triplicities or trigons are the astrological breakdowns of the Zodiac signs according to
the elements (fire, earth, air, water). Each Zodiac sign is ruled by a planet, one by day, and the
other by night. For example, the sign of Aries is ruled by the Sun during the day and by Jupiter at
night. In the table, in order to keep it short, planets are indicated by one letter (see table), and the
signs of the Zodiac are indicated by numbers: Aries - 0, Taurus - 1, Gemini - 2, Cancer - 3, Leo -
4, Virgo - 5, Libra - 6, Scorpio - 7, Sagittarius - 8, Capricorn - 9, Aquarius - 10, Pisces - 11.
Table 3 – Planets, their Arabic names, and short (single letter) designation.
Sun al-shams س الشمس Jupiter al-mushtari ے المشتري Saturn zuhal ل زحل Venus zuhara الزهرة
ه
Moon al-qamar ر القمر Mars al-mirrik خ المريخ Mercury al-utarid ک عطارد
Table 4 – Triplicities.
Cancer Scorpio Pisces Venus Mars Moon Mars Venus Moon
Gemini Libra Aquarius Saturn Mercury Jupiter Mercury Saturn Jupiter
Taurus Virgo Capricorn Venus Moon Mars Moon Venus Mars
Aries Leo Sagittarius Sun Jupiter Saturn Jupiter Sun Saturn
Triplicities Daytime ruler Nighttime ruler
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In the lower half of the disc a series of semi-circular scales are placed. Scales are not signed. Their
value will be given below. For convenience, we number them from I to VIII as shown in the
figure.
VIII – Mansions of the Moon
VII – Borders of Decans (10, 20, 30)
VI – Decan rulers
V – Term rulers
IV – Zodiac constellations
III – Length of Terms
II – Cotangent scale
I – Degree scale
Scales on the lower half of the back
The cotangent scales, which are located after the degree scale, made it possible to take the values
of these functions directly when measuring heights. To the left of the vertical line, there is a
duodenary scale, where the values of the cotangents are expressed in "fingers", i.e. 1/12, 2/12,
3/12, etc. On the right are the values in the "feet", i.e. 1/7, 2/7, 3/7, etc. For example, ctg 60 º =
0.577 (in the customary decimal system) = 7/12 (in the duodecimal system) / = 4/7 (in the
septenary system). So, for an angle of 60 degrees on the left scale, the alidade will indicate the
value 7, and on the right scale for the same angle, we will find the value 4, as it should be.
Therefore, it can be argued that these scales are made by an experienced master with skill, which
also indicates the authenticity of production.
The names of these two scales are written near the center. Calligraphic inscriptions are placed in
ornately shaped cartouches, decorated with flowers and additional lines. These inscriptions are
turned so that they are read from the center. Right one (in the picture) - fingers (ẓill-i aṣābic), left
one - feet (ẓill-i aqdām).
The Zodiac scale (scale IV) contains the names of 12 Zodiacal constellations, which begin on the
left side and go counterclockwise.
Table 5 – The Zodiacal constellation names.
Aries Taurus Gemini Cancer Leo Virgo
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حمل ثور ل جوزاء ل سرطان ال سد ال عذراء األ ال
hamal saur jauza saratan asad sunbula
Libra Scorpio Sagittarius Capricorn Aquarius Pisces
يزان م قرب ال ع قوس ال جدي ال و ال دل حوت ال الmizan akrab kaus jadi dalv hut
The TERMS (scales III and V) show the division of each degree of the Zodiac into five unequal
parts. Each term is ruled by a planet, the name of the planet on the scale is indicated by the last
letter of its Arabic name (as indicated in the table below). The method of division that we find
here is very ancient; it goes back to Ptolemy Tetrabiblos. And Ptolemy himself called this method
Egyptian, originating from the ancient Egyptian astrologers Nechepsos and Petrosiris (151 BC).
Such tables are to be found on many astrolabes from Lahore, including astrolabes from the
Museum of the East (Moscow). At the same time, our astrolabe is made with pinpoint accuracy
with no errors in the values of the length of terms (scale III). This accuracy proofs this astrolabe to
be the original and genuine instrument.
Table 6 – Term scales.
Zodiac
constellation
Ruling
planet
(scale V)
Length of
term
(scale III)
Aries
Jupiter 7
Venus 6
Mercury 8
Mars 5
Saturn 5
Taurus
Moon 8
Mercury 6
Jupiter 8
Saturn 5
Mars 3
Gemini
Mercury 7
Jupiter 6
Venus 5
Mars 7
Saturn 6
Cancer
Mars 7
Venus 5
Mercury 6
Jupiter 7
Saturn 5
Leo
Jupiter 6
Venus 5
Saturn 7
Mercury 6
Mars 6
Virgo
Mercury 7
Venus 10
Jupiter 4
Mars 7
Saturn 2
Zodiac
constellation
Ruling
planet
(scale V)
Length of
term
(scale III)
Libra
Saturn 6
Mercury 8
Jupiter 7
Venus 7
Mars 2
Scorpio
Mars 7
Venus 4
Mercury 8
Jupiter 5
Saturn 6
Sagittarius
Jupiter 12
Venus 5
Mercury 4
Saturn 5
Mars 4
Capricorn
Mercury 7
Jupiter 7
Venus 8
Saturn 4
Mars 4
Aquarius
Mercury 7
Venus 6
Jupiter 7
Mars 5
Saturn 5
Pisces
Venus 12
Jupiter 4
Mercury 3
Mars 9
Saturn 2
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Decans divide each of the Zodiac constellation term into three equal parts of 10 degrees. Decans
are also of ancient origin. The scale VI shows the name of the ruling planet for each decan. Here is
the full Arabic name of the planet: mirrīkh (Mars), shams (Sun), mushtarī (Jupiter), zuhra
(Venus), cauṭārad (Mercury), zuḥal (Saturn), and qamar (Moon). The scale VII with auxiliary
numbers 10, 20, 30 facilitates orientation on the scale.
Table 7 – Decans (scales VI, VII).
Zodiac
constellation
Decans
10 20 30
Aries Mars Sun Jupiter
Taurus Venus Mercury Saturn
Gemini Mercury Venus Saturn
Cancer Moon Mars Jupiter
Leo Sun Jupiter Mars
Virgin Mercury Saturn Venus
Libra Venus Saturn Mercury
Scorpio Mars Jupiter Moon
Sagittarius Jupiter Mars Sun
Capricorn Saturn Venus Mercury
Aquarius Saturn Mercury Sun
Pisces Mercury Mars Saturn
Scale VIII - Mansions of the Moon (Arabic manāzil) - the division of the Zodiac into sections that
the Moon passes in one day. Since the Moon moves completely around the celestial sphere once in
about 27.3 days (sidereal period), as observed from the Earth, the number of lunar mansions was
assumed to be either 27 or later - 28. In our case, there are 28 mansions, so in one Zodiac
constellation there are 2 1/3 mansions of about 13° 50'. Each mansion comes under a specific
group of stars. List of mansions [Ackermann, p. 76–79]:
Table 8 – Mansions of the Moon (scale VIII).
1 sharaṭān
2 buṭayn
3 thurayyā
4 dabarān
5 haq’a
6 han’a
7 dhirā’
8 nathra
9 ṭarf
10 jabha
11 al-zubra / al-kharātān
12 ṣarfa
13 ‘awwa’
14 simāk al-a’zal
15 ghafr
16 zubanā
17 iklil
18 qalb
19 shawla
20 al-na’ā’im’
21 balda
22 dhābiḥ
23 bula’
24 su’ūd
25 akhbiya
26 muqaddam
27 al-mu’akhkhar
28 baṭn al-hūt / al-risha’
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The names of the mansions are very neatly written.
ALIDADE has no scales - this confirms the late manufacturing of the tool. The target axis is offset
relative to the axis of rotation. There are two holes in the sighting device - large and small. The pin
has the rare form of a curved dagger or saber and not the traditional execution in the form of a
horse's head. Late astrolabe pins of the 18th century, stored in Greenwich, have a similar shape
[Charette, p. 267, 273].
Conclusion.
Unfortunately, the astrolabe has no direct indication of the year of its production and the name of
the master. This can be judged only by indirect data, such as scales design, a set of cities in the
gazetteer, a selection of stars on the spider, the composition of astrological information on the
back of the instrument, the design of the alidade and pin.
A number of factors (degree scale and pin shape, lack of scales on alidade) suggest the late
production of this tool - the end of the 18th - the beginning of the 19th century. However, the sets
of cities in the gazetteer and stars on the spider are made according to the rules of the craft of
much earlier instruments, dating back to the school of craftsmen from the city of Kerman of the
14th-15th centuries. The traditions of this school in the 16th-17th centuries were preserved in
Gilan, a city in the north of Persia and in Lahore, in India. It was here that the astrolabes were
made, having many common elements with earlier instruments from Kerman. One of such
instruments of 1522 is kept in Greenwich (with a later spider of the 18th century), in the National
Maritime Museum [Charette, Catalogue ..., p. 220-223], the second of 1587 - in the Museum of
the East in Moscow (unfortunately, of poor quality) [Maslikov, in production]. So we can say that
our astrolabe, although it is of late production, comes from very reputable precursors.
References:
Ackermann, S. Astrological scales on the National Maritime Museum astrolabes / S. Ackermann //
Astrolabes at Greenwich: a catalogue of the astrolabes in the National Maritime Museum.
– Greenwich. 2005. – P. 73–89.
Charette, F. Catalogue of Eastern astrolabes / F. Charette // Astrolabes at Greenwich: a catalogue
of the astrolabes in the National Maritime Museum. – Greenwich. 2005. P. 210–319.
Gibbs, S. Planispheric astrolabes from the National Museum of American History / S. Gibbs, G.
Saliba. – Washington: Smithsonian Inst. press, 1984. – 231 p. – (Smithsonian studies in
history and technology; № 45).
Maslikov, S., Sarma, S. R. A Lahore Astrolabe of 1587 at Moscow. Enigmas in its Construction /
S. Maslikov, S. R. Sarma // Indian Journal of History of Science. – 2016. – Vol. 51, Issue 3. –
P. 454–477.
Morrison, J. E. The astrolabe / J. E. Morrison. – Janus, 2007. –437 p.
Maslikov, S., Persian roots of Lahore astrolabe. In production.