The nakshatra are classified in to Chara, Sthira, Mrdu, Ugra, Tikshna, Kshipra and Mishra. Based on these qualities, they are suitable for various activities. These are extensively used in muhurtha. For instance, for coronation, planting of trees etc. the Sthira Nakshatras are favourable as they offer fixity. On the other hand, activities such as commercial transactions, taking medicine, travels etc. should be done in Kshipra Nakshatras, as they last for short duration. Depending on the Nakshatra occupied by Chandra, Lagna, Chandra Rashyesha and Lagnesha, the native either faced with certain kinds of activities or he is fond of doing certain activities. The Chandra Nakshatra and Chandra Rashyesha Nakshatra indicate what environment the native is put into (Chandra = Environment), while the Lagna and Lagnesha nakshatra indicate what the native likes to do (Lagna = own thought and action).
- Chara Nakshatra: Movable: Saravana, Dhanishta, Satabhisha, Punarvasu and Swati are movable. They are auspicious for activities needing movements such as acquiring vehicles, gardening, going on procession etc.
- Sthira Nakshatras: Fixed: Rohini, Uttaraphalguni, Uttarashadha and Uttarabhadra are fixed. They are favourable for activities that require fixity such as coronations, laying the foundations of cities, sowing operations, planting trees etc.
- Mrdu Nakshatras: Tender: Chitra, Anuradha, Mrigashira and Revati are soft. They are favourable for activities pertaining to subtle things such as wearing new apparel, learning dancing, music and fine arts, sexual union, performance of auspicious ceremonies etc.
- Ugra Nakshatras: Violent: Bharani, Magha, Purvaphalguni, Purvashadha, and Purvabhadra. These constellations are favourable for activities that requires violence, force, weapons, confronting enemies etc. Activities such as demolishing a structure, setting fires, capturing others with force, battles etc. are favoured in this Nakshatra.
- Tikshna Nakshatra: Sharp: Moola, Jyeshta, Ardra and Ashlesha are sharp. They are favourable for destructive activities such as incantations, invoking spirits, imprisonment, murders (marana mantra), separation of friends (ucchatana mantra) etc.
- Kshipra Nakshatra: Swift: Ashvini, Pushya, Hasta and Abhijit are Swift constellations. They are favourable for activities involving swiftness such as putting ornaments, pleasures and sports, administering medicine, starting industries, undertaking travels etc.
- Mishra Nakshatra: Mixed: Krttika and Vishakha are mixed constellations. They are favourable for activities like worshiping, fire ceremonies, purchasing furniture and electronics.
In Hora Ratnam verses 518 to 520, it is mentioned that according to Sage Saunaka, birth in different classes of nakshatras bestow following nature on the native:
- Dhruva Nakshatra: Stable, forgiving
- Chara Nakshatra: Fickle minded, eat indiscriminately
- Ugra Nakshatra: Fierce, torture, confine others
- Mishra Nakshatra: Mixed, equal treatment to friends and foes
- Laghu Nakshatra: Limited enjoyment
- Mrdu Nakshatra: Promote quarrels, speak ill and dirty (Note: There appears to be some corruption of the text as there is a difference between the name “Mrdu” and the given nature).
The classification of the nakshatras are as follows:
(1) Ashvini: Ksipra, (2) Bharani: Ugra, (3) Krttika: Mishra, (4) Rohini, (5) Mrgashira: Mrdu, (6) Ardra: tikshna (7) Punarvasu, (8) Pushya: Ksipra, (9) Ashlesha: tikshna
(10) Magha, (11) Purvaphaguni: Ugra, (12) Uttaraphalguni: Sthira, (13) Hasta: Ksipra, (14) Chitra: Mrdu, (15) Svati: Chara, (16) Vishakha: Mishra, (17) Anuradha: Mrdu, (18) Jyeshtha: tikshna
(19) Moola: tikshna, (20) Purvashadha: Ugra, (21) Uttarashadha: Sthira, (22) Sravana: Chara, (23) Dhanishtha: Chara, (24) Shatabhisha : Chara, (25) Purvabhadra: Ugra, (26) Uttarabhadra: Sthira, (27) Revati: Mrdu
Narada Purana 56.177: The (four) asterisms Rohini, Uttara-phalguni, Uttaraasadha and Uttarabhadra are ‘fixed’ (sthira). The (three) asterisms Hasta (Surya), Asvini and Pusya are ‘swift’ (Ksipra). Visakha (Dvidaivatya) and Krttika (Vahnibha) are ‘Mixed (Mishra)’.
Narada Purana 56.178: The (five) asterisms Dhanistha (Vasu), Punarvasu (Aditya), Satabhisa (Ambu), Svati and Sravana (Visnu) are ‘moving’ (Chara). The (four) asterisms Mrgasira (Indu), Anuradha (Mitra), Chitra and Revati (Antya) are ‘soft’ (Mrdu). And, the (five) asterisms Purvaphalguni, Purvasadha, Purvabhadrapa, Magha and Bharani (Antaka, Yama) are ‘violent’ (Ugra).
Narada Purana 56.179a: The (four) Asterisms Mula, Ardra, Ashlesha (Indra) and Jyeshtha (Indra) are ‘sharp’ (tikshna). All have effects in consonance with their nomenclatures.
Muhurtha Chintamani suggested that the qualities of the Nakshatras are even more accentuated when they coincide with certain days (Vedic Vara, starting at Sunrise). They are (1) Fixed-Sunday, (2) Movable-Monday, (3) Violent-Tuesday, (4) Mixed-Wednesday, (5) Swift-Thursday, (6) Soft-Friday, (7) Sharp-Saturday. This is logical as the grahas ruling the mentioned weekdays also imbibe the same qualities as that of the Nakshatras. For instance Surya is the most steady Graha, hence it is mapped to Sthira Nakshatras; Chandra is the fastest Graha among the Navagrahas, hence it is mapped to Chara Nakshatras and so on.
Muhurtha Chintamani: (1) Dhruva: Uttaraphalguni, Uttarashadha, Uttarabhadra, Rohini on a Sunday, 4 nakshatras; (2) Chara: Swati, Punarvasu, Sravana, Dhanishtha, Shatabhisha on Monday, 5 nakshatras; (3) Ugra: Purvaphalguni, Purvaashadha, Purvabhadra, Bharani, Magha on Tuesday, 5 nakshatras; (4) Mishra: Vishakha, Krttika, On wednesday, 2 nakshatras; (5) Laghu: Hasta, Asvini, Pushyami, Abhisit, on Thursday, 4 nakshatras; (6) Mrdu: Mrgashira, Revati, Chitta, Anuradha, on Friday, 4 nakshatras; (7) Tikshna Mula, Jyeshtha, Ardra, Ashlesha, on Saturday, 4 nakshatras.