Today we will look at the form मघा fNs from श्रीमद्वाल्मीकि-रामायणम् 1.71.24.

मघा ह्यद्य महाबाहो तृतीयदिवसे प्रभो ।
फल्गुन्यामुत्तरे राजंस्तस्मिन्वैवाहिकं कुरु ।
रामलक्ष्मणयोरर्थे दानं कार्यं सुखोदयम् ∥ १-७१-२४ ∥

Translation – “Indeed the constellation Maghā is in the ascendant today, O mighty-armed king! On the third day, when the celebrated Uttarā Phalgunī mansion is in the ascendant, my lord, perform the wedding ceremony. Charity, which is calculated to bring happiness in its wake, should be made for the welfare of Śrī Rāma and Lakṣmaṇa (4).”

अद्य मघा (‘मघया युक्तो मघा कालोऽद्य वर्तते’ इति भावः) – Today is Maghā (meaning that – the time in which the moon is in conjunction with the constellation Maghā, occurs today.)

(1) मघा टा + अण् । By 4-2-3 नक्षत्रेण युक्तः कालः – To denote a time (in which the moon is) in conjunction with a particular constellation, the तद्धित: affix ‘अण्’ (prescribed by 4-1-83 प्राग्दीव्यतोऽण्) may be optionally applied following a syntactically related पदम् in which the सन्धिः operations have been performed, provided the पदम् ends in a third case affix and has a base denoting that particular constellation.

Note: ‘मघा टा + अण्’ gets the designation प्रातिपदिकम्‌ by 1-2-46 कृत्तद्धितसमासाश्च। This allows 2-4-71 सुपो धातुप्रातिपदिकयोः to apply in the next step.

(2) मघा + अण् । By 2-4-71 सुपो धातुप्रातिपदिकयोः – A सुँप् affix takes a लुक् elision when it is a part of a धातुः or a प्रातिपदिकम्।

(3) मघा । By 4-2-4 लुबविशेषे – To denote a time (in which the moon is) in conjunction with a particular constellation, the तद्धित: affix ‘अण्’ (prescribed by the prior सूत्रम् 4-2-3 नक्षत्रेण युक्तः कालः) takes the लुप् elision, provided the entire 24-hour (60-ghatikā) day is being specified and not any sub-division of it.

Note: The सूत्रम् 1-1-63 न लुमताङ्गस्य prevents the सूत्रम् 7-2-117 तद्धितेष्वचामादेः from applying.

As per the सूत्रम् 1-2-51 लुपि युक्तवद्व्यक्तिवचने – When an affix takes the लुप् elision, then the gender and number of the derived form follows that of the base.

Therefore, the derived प्रातिपदिकम् ‘मघा’ is declined in the feminine singular, complying with the gender and number of the base ‘मघा’। Hence प्रथमा-एकवचनम् is मघा।

Similarly, we can derive the following –
१) अद्य पुष्यः (‘पुष्येण युक्तः पुष्यः कालोऽद्य वर्तते’ इति भावः)।
२) अद्य कृत्तिकाः (‘कृत्तिकाभिर्युक्तः कृत्तिकाः कालोऽद्य वर्तते’ इति भावः)।