An Indo Persian brass Astrolabe, Lahore school, signed by Diya' al-Din Muhammad Ibn Qa'im Muhammad Asturlabi Humayuni al-Lahuri, dated A.H.1064/A.D.1653

composed of a mater ('umm) cast in one piece with the high, symmetrically fretted kursî, the tracery of which is engraved with stylised leaf decoration, carrying a shackle and ring, limb engraved with a scale of degrees in four quadrants numbered by groups of six, the interior of the mater carrying geographical scales and fitted with a bottom lug for locking the four plates in place.  Three of the plates serve latitudes 32, 34 and 36 degrees above and below.  In addition there are markings for the horizons and for latitute 66.5 degrees, the latter serving the conversion of equatorial and ecliptic coordinates.  The mater is engraved with a gazetteer displaying longitudes and latitudes for 54 localities in Greater Iran and India.  The upper back bears a sexagesimal (base 60) trigometric grid and a solar altitude scale with graphical markings for latitudes 27 and 32 degrees.  In the lower two quadrants is a double shadow square of seven (right) and twelve (left) numbered divisions which correlate with the similarly numbered cotangent scales on the edge of the instrument. Within the shadow square is a numbered table of the twenty eight mansions of the Moon.The alidade is apropriately marked for use with the sexagesimal markings and for use as a universal sundial. 

In good overall condition, minor rubbing and patination consistent with age, as viewed.
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This astrolabe is a typical production of the prolific school of instrument makers of 17th-century Lahore with one significant distinguishing feature.  This is the elegant and charming floral decoration on the rete, which though rare, is attested on a few Lahore pieces.  In style the rete is close to that of the somewhat larger  astrolabe known as Jaipur B (CCA 75; Gunther I, 206-7) dated 1657 AD.  The realistic plant form used on these two retes distinguishes them from most of the retes fitted to the hundred odd astrolabes surviving from the Lahore workshops on which the leaf forms are more stylised and formal, less pointed in form.  By contrast the treatment of the open-work kursî, although this resembles, in simplified form, that of the Jaipur B astrolabe, employs a more rudimentary leaf decoration which is closer to that employed on the kursî of the astrolabe by Muhammad Muqîm ibn 'Isâ dated AH 1053 [= AD 1643/44] now in the Museum of the History of Science, Oxford (CCA 72;  Gunther I, 197-99).  The ogival form and tracery of the kursî on each of the three instruments is however very close.

The absence of an east-west bar from the rete of this astrolabe is highly unusual.  Distinctive also is the inclusion of a double latitude plate and a plate giving the ecliptic co-ordinates of the stars shown on the rete.  Both of these are complexities characteristic of Lahore astrolabists.  Both can be found for example in an astrolabe by  Muhammad b. 'Isâ dated AH 1044[= AD 1634/35, CCA.71; Gunther I, 191-97].

For the astrolabes mentioned see Robert T. Gunther, The Astrolabes of the World..., 2 vols , Oxford 1932.

For Lahore instrument-making workshops see S. R. Sarma, 'The Lahore Family of Astrolabists and their Ouvrage', Studies in History of Medicine and Science xiii 1994, 205-24 reprinted in Sreeramula Rajeswara Sarma, The Archaic and the Exotic. Studies in the History of Indian astronomical Instruments, Manohar 2008, Ch. 10.

A comparable astrolabe by Diya al-Din al-Lahuri was sold in these rooms 9 April 2008, lot 212.