Declension table of ?sūryayantra

Neuter	Singular	Dual	Plural
Nominative	sūryayantram	sūryayantre	sūryayantrāṇi
Vocative	sūryayantra	sūryayantre	sūryayantrāṇi
Accusative	sūryayantram	sūryayantre	sūryayantrāṇi
Instrumental	sūryayantreṇa	sūryayantrābhyām	sūryayantraiḥ
Dative	sūryayantrāya	sūryayantrābhyām	sūryayantrebhyaḥ
Ablative	sūryayantrāt	sūryayantrābhyām	sūryayantrebhyaḥ
Genitive	sūryayantrasya	sūryayantrayoḥ	sūryayantrāṇām
Locative	sūryayantre	sūryayantrayoḥ	sūryayantreṣu

Compound sūryayantra -

Adverb -sūryayantram -sūryayantrāt