what are Lunar station and Nakshatras ?

Lunar station

A lunar station, also called a lunar mansion or lunar house, is a segment of the ecliptic through which the Moon passes in its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical system. In general, though not always, the zodiac is divided into 27 or 28 segments relative to the fixed stars – one for each day of the lunar month. (A sidereal month lasts about 27.3 days.) The Moon's position is charted with respect to those fixed segments. Since the Moon's position at given stage will vary according to Earth's position in its own orbit, lunar stations are an effective system for keeping track of the passage of seasons.

Various cultures have used sets of lunar stations astrologically; for example, the Jyotisha astrological nakshatras of Hindu culture, the Arabic manzils , the Twenty-Eight Mansions of Chinese astronomy, and the 36 decans of Egyptian astronomy.

Nakshatras

Nakshatra (Sanskrit: नक्षत्र) is the term for lunar mansion in Indian astrology and Astronomy. A nakshatra is one of 28 (sometimes also 27) sectors along the ecliptic. Their names are related to a prominent star or asterisms in or near the respective sectors.

In Hindu astronomy, there was an older tradition of 28 Nakshatras which were used as celestial markers in the heavens. When these were mapped into equal divisions of the ecliptic, a division of 27 portions was adopted since that resulted in a cleaner definition of each portion (i.e. segment) subtending 13° 20′ (as opposed to 12° ​51 3⁄7′ in the case of 28 segments). In the process, the Nakshatra Abhijit was left out without a portion. The Surya Siddhantha concisely specifies the coordinates of the twenty seven Nakshatras.

It is noted above that with the older tradition of 28 Nakshatras each equal segment would subtend 12.85 degrees or 12° 51′. But the 28 Nakshatra were chosen at a time when the Vedic month was recognised as having exactly 30 days.

list of Nakshatras:

1. Ashvinī. - (β and γ Arietis), (0°00′ – 13°30′ Aries)
2. Bharanī
3. Kṛttikā  -Pleiades (26°40′ Aries to 10° Taurus)
4. Rohinī
5. Mrigashīra-BELLATRIX , PI2, PI3,PI4-ORIONIS
6. Ārdrā
7. Punarvasu
8. Pushya
9. Ashlesha (nakshatra)
10. Maghā
11. Pūrva Phalgunī (Pubbha)
12. Uttara Phalgunī (Uttara)
13. Hasta
14. Chitrā (Spica)
15. Svātī (Arcturus)
16. Vishākhā
17. Anurādhā
18. Jyeshtha
19. Mūla
20. Pūrva Ashādhā
21. Uttara Ashādhā
22. Shravana
23. Dhanistha
24. Shatabhisha
25. Pūrva Bhādrapadā
26. Uttara Bhādrapadā
27. Revatī
28. Abhijit

source : wikipedia