अश्विनौ / Equinoxes and अरुणाचल शिव / aruṇācala śiva.

अश्विनौ परिक्राम्यन्तौ वत्सरे सं अचले,
कालवृत्ते प्रदक्षिणया सततं अरुणाचलं ॥
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aśvinau parikrāmyantau vatsare saṃ acale,
kālavṛtte pradakṣiṇayā satataṃ aruṇācalaṃ ||
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Equinoxes move around the Timeless Immovable Shiva (Mahākāla).They traverse the path encircling aruṇācala, and complete one pradakṣiṇā in one solar year.
Just as हाटकेश्वर / hāṭakeśvara is shiva in the पाताल / pātāla, So is He all over the existence.
( हाटकेश्वर तु पाताले / hāṭakeśvara tu pātāle )

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And if we consider the 2 equinoxes + 2 solstices as the legs of the cosmic horse this becomes one great vehicle of the Lord Mahākāla, Btw.
अश्व > aśva and, ऊक्षन् > ūkṣan are the संस्कृत पद / saṃskṛta pada (terms)  for horse and ox / oxen respectively, meaning the same as horse and the bull.
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Btw. :
There is a constellation अश्विनी / aśvinī which is the first of the 27 constellations in Vedika calandar. अभिजित / abhijita is the last but is part of अश्विनी / aśvinī which constitute the whole zodiac. These are celestial 'beings' and not only inert objects like stones. Though stones too are 'beings' in Self. That may be one reason why we worship stone Lingam.
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