Alkhiba alshami

Authors: Khalid Al-Ajaji, Youla Azkarrula, Susanne M Hoffmann

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Alkhiba (Arabic: الخباء, al-Ḫibāʾ, "the small tent") is an asterism of four stars forming a quadrilateral shape in the constellation Hercules. Its name is Arabic and is reported by both astronomers and anwāʾ authors of the 9th and 10th century.

Etymology

Headword (Arabic): الخِبَاء Transliteration: al-Ḫibāʾ IPA: /al.xɪ.baːʔ/

Alkhiba (Arabic: الخباء, from the Arabic root خبي) denotes a small tent.

Lisān al-ʿArab defines al-Ḫibāʾ as:

الخِباءُ مِنَ الأَبنية: وَاحِدُ الأَخْبية، وَهُوَ مَا كَانَ مِنْ وَبَر أَو صُوفٍ وَلَا يَكُونُ مِنْ شَعَر، وَهُوَ عَلَى عَمُودَيْنِ أَو ثَلَاثَةٍ، وَمَا فوقَ ذَلِكَ فَهُوَ بَيْت.

Al-Ḫibāʾ (الخِبَاء) is a tent made of camel wool or sheep’s wool, never of goat hair. It usually stands on two or three poles; anything larger than that is called a bayt (large tent).

Concordance

Alkhiba is an asterism of the quadrilateral ζ, ε, π, η Her corresponding exactly to the stars of the Hercules Keystone. It should not be confused with another similar asterism carrying the same name in the constellation Corvus, formed by γ, ε, β, δ, distinguished by Ibn Qutayba as the Southern Tent (Arabic: الخباء اليماني, al-Ḫibāʾ al-Yamānī). Therefore, it is recommended to refer to the asterism in Hercules as the Northern Tent (Arabic: الخباء الشآمي, al-Ḫibāʾ ash-Šāmī).

History

Three primary sources discuss the Arabic Northern Tent (الخِبَاء الشآمي, al-Ḫibāʾ ash-Šāmī): Ibn Qutayba, al-Marzūqī, and al-Ṣūfī. Their accounts differ, and to elucidate the significance of al-Ḫibāʾ, one must compare it to other distinctly named stellar configurations that bear analogous nomenclature.

To understand how the Arabs imagined al-Ḫibāʾ, we can look at two well defined Ḫibāʾ asterisms at our disposal. The first is al-Ḫibāʾ al-Yamānī (Arabic: الخباء اليماني, "the Southern Tent"), which corresponds to an asterism of four quadrilateral stars γ, ε, β, δ in Corvus.

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  Southern Tent (الخباء اليماني), alḪibāʾ alYamānī in Corvus.
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  Arabian Khiba tent. image inspired by a century old photo in Matson collection in Library of Congress.

The other is Saʿd al-Aḫbiya (سعد الأَخْبِيَة), an asterism of four stars in Aquarius: three form a triangle, which is al-Ḫibāʾ (the tent), and the fourth star inside the triangle is Saʿd (a man inside the tent). This description is given by Ibn Qutayba, al-Marzūqī, and al-Ṣūfī. Al-Ṣūfī said:

سَعْدَ الأَخْبِيَةِ، وهو المنزل الخامس والعشرون من منازل القمر، سُمِّيَ بهذا الاسم لأنه من أربعة كواكب: ثلاثة منها على مثلث، وواحد في وسط المثلث وهو الحادي عشر، فجعلوا هذا الواحد سعدًا والثلاثة له بمنزلة الخباء.

Saʿd al-Aḫbiya ("Saad of the Tents"), the twenty-fifth of the lunar stations, was given this name because it consists of four stars: three form a triangle, and one lies at the center of that triangle — the eleventh star of Aquarius. They considered the central one Saʿd, and the three surrounding it like the tent that shelters Saʿd.

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  Saʿd al-AḪbiya, in Aquarius.
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  Arabian Khiba tent supported by one pole. image inspired by a century old photo in Matson collection in Library of Congress

Ibn Qutayba (d. 276 H / 889)

The complete text describing the Northern Tent (al-Ḫibāʾ ash-Šāmī) reads:

Original Arabic

وأولاد الظباء كواكب صغار، فيما بين الظباء والنفزات، وعن يمين نفزات الظباء كواكب مستديرة غير متقارنة، تسمّى: الحوض. والخباء أسفل من الحوض، كواكب في مثل هيئة الخباء اليمانية.

English translation

The fawns, awlād al-Ẓibāʾ (أَوْلادُ الظِّبَاءِ), are small stars located between al-Ẓibāʾ (الظِّبَاءِ) and the Gazelle Leaps (النَّفَزَاتِ). To the right of the Gazelle Leaps (نَفَزَاتِ الظِّبَاءِ), there are round, non-aligned stars called al-Ḥawḍ (الحَوْضَ, "the Pool").

Below al-Ḥawḍ lies al-Ḫibāʾ (الخِبَاءُ, "the Tent"), a group of stars shaped like the southern tent (الخِبَاءِ اليَمَانِيَّةِ).

Stars identification

It appears that al-Ḫibāʾ (الخِبَاءُ), as described by Ibn Qutayba, denotes a quadrilateral configuration of four stars, reflecting the form of the southern tent (al-Ḫibāʾ al-Yamānīyah, الخِبَاءِ اليَمَانِيَّةِ). Two such arrangements meet this criterion: one located beneath al-Ḥawḍ at its rising, and another beneath al-Ḥawḍ at its setting. The first consists of the four stars of the Big Dipper, which may be discounted since these are well known stars, and Ibn Qutayba would likely have acknowledged this alternate designation. The other candidate is the quadrilateral formed by 15 Lyn, δ Aur, and α, β Cam.

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  Al-Ḫibāʾ as described by ibn Qutayba.

Al-Ṣūfī (d. 376 H / 986)

The complete text describing the Northern Tent (al-Ḫibāʾ ash-Šāmī) reads:

Original Arabic

وفي القطعة من السماء التي حواليها هذه الصورة ورأس الدب الأكبر والجَدْيُ وكوكبة ذات الكرسي، وهي رقعة من السماء شبه مفازة ليس فيها كوكب نيِّر ولا شيء من الكواكب المرصودة إلا الاثنين اللذين على الرأس من هذه الصورة، وفيها من الكواكب ما لا يمكن إحصاؤه لكثرته وكثافة جمعه، وفي الوسط منها، كواكب من القدر الخامس والسادس، تُسَمِّيها العرب: الخِبَاءَ؛ لأنّها على صورة الخباء، والاثنان اللذان على الرأس من هذه الصورة داخلان في جملة الخباء.

English translation

In the region of the sky surrounded by this constellation (referring to the constellation of Auriga), along with the head of the Great Bear, Polaris, and the constellation Cassiopeia, there is an area with no bright star, nor any reported by Ptolemy except for the two at the head of Auriga. This area contains countless stars, densely packed together. In its center are stars of fifth and sixth magnitude, which the Arabs call al-Ḫibāʾ (الخِبَاءُ, "the Tent") because they resemble the shape of a tent. The two stars at the head of this constellation are considered part of al-Ḫibāʾ.

Stars identification

It is evident from the description that al-Ḫibāʾ (الخِبَاء) refers to a region of the sky encompassing numerous stars, including the two on the head of Auriga, δ and ξ Aur. Restricting the definition to only a specific number of stars does not align with the account given by al-Ṣūfī.

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  Al-Ḫibāʾ region as described by al-Ṣūfī.

Al-Marzūqī (d. 421 H / 1030)

The complete text describing the Northern Tent (al-Ḫibāʾ ash-Šāmī) on the authority of Ibn al-Aʿrabī (d. 230 H / 845) reads:

Original Arabic

وقال [ابن الأعرابي]: أسفل من بَنَاتِ نَعْشٍ كواكب كثيرة مختلطة يقال لها: الضِّبَاعُ. وأَوْلَادُ الضِّبَاعِ كواكب صغار، عن يمين الضِّبَاعِ، بينها وبين بَنَاتِ نَعْشٍ. قال: والخِبَاءُ كواكب في مثل هيئة الخِبَاءِ، أسفل من أَوْلَادِ الضِّبَاعِ.

English translation

[Ibn al-Aʿrabī] said: Below Banāt Naʿsh (بَنَاتِ نَعْش) are numerous, scattered stars called al-Ḍibāʿ (الضِّبَاعُ, "the hyenas"). Awlād al-Ḍibāʿ (أَوْلَادُ الضِّبَاعِ, "the young hyenas") are small stars located to the right of al-Ḍibāʿ, between them and Banāt Naʿsh. He also said: al-Ḫibāʾ (الخِبَاءُ) is a group of stars resembling the shape of a tent, situated below Awlād al-Ḍibāʿ (أَوْلَادُ الضِّبَاعِ, "the young hyenas").

Stars identification

Al-Marzūqī places al-Ḫibāʾ in spatial relation below al-Ḍibāʿ. From the text we can easily find a quadrilateral shape with relatively bright stars as described in the region of the constellation Hercules. The location of this tent fits nicely with the nearby shepherd with his goats and two dogs in the middle of a desert pasture. Notably, his description is clearer than those of Ibn Qutayba and al-Ṣūfī and corresponds well with the arrangement of stars in the night sky. According to his narrative, al-Ḫibāʾ refers to the four stars ζ, ε, π, η Her.

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  Al-Ḫibāʾ as described by al-Marzūqī.

Adopted identification

Based on the concordance of star positions and the historical descriptions, al-Marzūqī account is adopted for al-Ḫibāʾ in Hercules (Northern Tent) as the preferred identification. In this article, al-Ḫibāʾ ash-Šāmī denotes the quadrilateral ζ, ε, π, η Her, corresponding to the Hercules Keystone, and is distinguished from al-Ḫibāʾ al-Yamānī in Corvus.