Dhanuśarāgra (धनुशराग्र)

Authors: Shylaja, Susanne M Hoffmann, ASE Tech Team, IanRidpath

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Dhanusharagra is in the red circle envelopes both the stars. Image from Sidney Hall Urania, wikicommons

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Etymology and History

Name Variants

• Dhanuśarāgra (धनुशराग्र)
• Dhanusharagra

Origin of Constellation

The term Dhanuśarāgra (धनुशराग्र) literally means tip of the arrow. Dhanu - bow, śara - arrow, agra - tip. It agrees with the position corresponding to the tip of the arrow. There are two stars γ1 and γ2, shown inside the red circle in the diagram. Although the original diagram responsible for the nomenclature is not traceable, the depiction here supports the etymology of the name .

This star name thus can be for γ1 Saggittarii.

Transfer and Transformation

This name has been found in the catalogue of astrolabes translated from Persian. The names in these star lists of the dials have been coined based on their position.

The astrolabes were introduced in to Indian astronomy by sea farers from the Middle East. In the first manual prepared by Mahendra Suri in the 1370CE only 32 bright stars were listed. Subsequently other faint stars also were marked. Based on the original data, the stars names were literally translated in most of the cases. The name is listed in the earliest manual by Mahendra Suri as the 26th star. It may be seen that there was no Persian name for this. Therefore, this must have been coined to suit the imaginary picture.

The list from Mahendra Suri (1370CE) assigns number 26

In the astrolabe C006 (1644CE) made by Maniarama from Gujarat, India, the stars are marked with two letter abbreviations and the numeral corresponding to the list of Mahendra Suri. Dhanu 26 on the rete, therefore, will correspond to Dhanusaragra. The close up view here shows the pointer on the rete. Using Spica (S) and Altair (A) as references, we see that the pointer is for a star in Ophiucus.

Close up of the region showing numbers 26 Dhanu and 27

Stars overlay on the rete; reference stars are Altair (A) and Spica (S)

C001 in the catalogue was prepared by Damodara of Ahmedabad in 1605. The engraving on the dial reads Dhanusira; however, the catalogue reports Dhaunusaragra as a correction. This is a curious case of mis-identification. The position on the rete matches with neither Dhanusira (μ Sgr) nor Dhanusaragra (γ Sgr). However, this brings out the information that these two star names were in use.. The position actually corresponds to the supernova of 1604 CE.

The region of Dhanusharagra in C001 shows the pointer to the location of the SN1604

This table shows that the star was misidentified as mu Sgr in the catalogue

The accuracy of the star dials cannot distinguish between the two stars γ 1 and γ2.

References

• References (general)