sandhikal ya sankraman kal sadaiv se hi ashubh, hanikarak, kashtadayak evan asmanjspurn mana jata raha hai. sandhi se tatparya hai ek ki samapti tatha dusre ka praranbh, chahe vah samay ho ya sthan ho ya paristhiti ho. rituon ke sandhikal men rogon ki utpatti hoti hai. din v ratri ke sandhikal men ish vandna ki jati hai. shasan prashasan ke sandhikal men janta ko kashton ka samna karna padta hai. kamre v baramde ke madhya (dahlij par) shubh karya varjit hai. do prakar ke margon ke milan sthal par savdhani suchak chetavni patt lage hote hain. vardan prapt karne par bhi hiranyakashyap ka jis prakar ant hua vah bhi sandhi ka hi udaharan hai.
jyotish men aisi hi sandhikalin sthiti ke anek udaharan hain, jaise surya sankranti, nakshatra sandhi, rashi sandhi, tithi sandhi, lagn sandhi, bhav sandhi dasha sandhi adi. aisi sandhiyon men janme jatak ko bhari vipattiyon ka samna karna padta hai. is prakar ke sandhikalon men shubh karya, vivah, yatra adi varjit hain. ham yahan aisi sandhi par vichar karenge jismen do prakar ki sandhiyan yatha nakshatra sandhi tatha rashi sandhi ek sath ati hai.
rashiyon men 27 nakshatron ka vitaran karne ke lie bhachakra ko 120 ansh ke tin tritiyanshon men banta gaya hai. ek tritiyansh (120 ansh) men 9 nakshatra, 36 charan tatha 4 rashiyan ati hain. tinon tritiyanshon men 9-9 nakshatron ki avritti nakshatra svami ke anusar saman rup se hai. pratyek tritiyansh ketu ke nakshatra (kamshah 1 ashvini, 10 magha tatha 19 mul) se praranbh hota hai tatha budh ke nakshatra (kramshah 9 ashlesha, 18 jyeshtha tatha 27 revti) par samapt hota hai.
yadi ham rashiyon ke vitaran par dhyan den to spasht hoga ki pratyek tritiyansh agni tatva rashi (kramshah mesh, sinh tatha dhanu) se praranbh tatha jal tatva pradhan rashi (kramshah kark, vrishchik tatha min) par samapt hota hai. 0 ansh, 120 ansh tatha 240 ansh ko isi adhar par janmakundli men bhi trikonon ki sangya di jati hai. ye bindu kramshah lagn, pancham tatha nakshatra bhavon ke praranbh mane jate hain. ye tinon bindu aise sthanon par hain jahan nakshatra v rashi donon ek sath samapt evan praranbh hote hain arthat ye bindu nakshatra evan rashi ke sanyukt sandhi sthal han. 1. 0 ansh par revti (min) samapt hokar ashvini (mesh) se praranbh hota hai. 2. 120 ansh par ashlesha (karka) samapt hokar magha (sinh) se praranbh hota hai. 3. 240 ansh par jyeshtha (vrishchik) samapt hokar mul (dhanu) se praranbh hota hai.
uparyukt samapt hone vale nakshatron (revti, ashlesha v jyeshtha) ka svami budh hai tatha tinon sanbandhit rashiyan (min, kark tatha vrishchik) jal tatva pradhan hain. isi prakar praranbh hone vale nakshatron (ashvini, magha, v mul) ka svami ketu hai tatha tinon sanbandhit rashiyan (mesh, sinh v dhanu) agni pradhan hain. budh ke nakshatra rajoguni tatha ketu ke nakshatra tamo guni hain. is prakar ye bindu rashiyon ke anusar agni tatha jal ke sangam sthal tatha nakshatron ke anusar raj aur tam ke hain. inhin ke adhar par ye sandhi sthal kshobhpurn, ashant, visfotak evan tufani hone ke karan ashubh mane jate hain.
atah nakshatron ke ye tin yugm yatha revti+ashvini, ashlesha+mgha tatha jyeshtha+mul gandmul sangyak nakshatra kahlate hain. yadi jatak ka tatkalik chandra spasht uparyukt rashyanshon men ho to uska janm gandmul nakshatra men mana jana chahie. bade v chote mul: mul, jyeshtha v ashlesha bade mul kahlate hain tatha ashvini, revti v magha chote mul hain. bade mulon men janme jatak ke lie janm ke 27 din bad chandrama jab usi nakshatra men ata hai tab mul shanti karai jati hai. tab tak pita balak ka munh nahin dekhta. chote mulon ki shanti 10ven din athva 19ven din jab usi svami ka dusra ya tisra nakshatra (anujanm ya trijanma) ata hai tab karai ja sakti hai.
gandant mul: sandhi ke adhikadhik nikat gandmulon ki ashubhta men aur bhi vriddhi ho jati hai. 0, 120 v 240 ansh to atyant hi sanvednshil bindu hain, kyonki vahin jal aur agni ka vastavik milan hota hai. aise samay men jatak ka janm hona atyant hi duvidhajanak hota hai. ya to aisa balak jita hi nahin, yadi ji jae to fir vishesh rup se vikhyat hota hai. parantu mata-pita ke lie atyant kashtakari hota hai. saravli ke is shlok se ukt ki pushti hoti hai. ‘‘jato n jivti maro matur pathyo bhavetsvakulahanta. yadi jivti gandante bahugjturgo bhaved bhuyah..’’ sandhi ke atyant nikat vale bhag ko gandant mul ki sangya di jati hai.
prachin vidvanon ke anusar nakshatra yugm ke pichle nakshatra ki antim 2 ghatiyan tatha agle nakshatra ki pratham do ghatiyan (lagatar 4 ghatiyan) gandant mul ki shreni men ati hain. in vidvanon ne pratyek nakshatra men chandrama ka bhabhog 60 ghati manakar vyakt kiya hoga parantu chandrama ka pratyek nakshatra men bhabhog saman nahin rahta. atah is samay sima ke bajay konatmak man men parivartan karna upyukt raha. 60 ghati men se 2 ghati ka arth 800 kala ka 2/60 arthat 800 x1/30 arthat 800 x 1/30 = 26 kala 40 vikla konatmak man hota hai. uparyukt ganna ke adhar par gandant mul sangyak nakshatron ka konatmak vistar nimnanusar hona chahie.
abhukt mul: jyeshtha nakshatra ke ant ki ek ghati (24 mint) tatha mul nakshatra ki pratham ek ghati (24 mint) abhukt mul kahlati hai. uparyukt gannanusar 2 ghati ka konatmak man 26 kala 40 vikla hota hai, atah ek ghati ka konatmak man 13 kala 20 vikla hua. iske anusar abhukt mul ka konatmak vistar nimnanusar hota hai. alg-alag vidvanon ke anusar ukt ghatiyon ki sankhya bhinna-bhinn hain. parantu kul milakar dekha jae to jyeshtha ka chaturth charan tatha mul ka pratham charan sarvadhik hanikarak hai.
samanya rup se tritiyanshon ke antim nakshatron (revti, ashlesha v jyeshtha) ke pratham charnon se jyon-jyon chaturth charnon ki or (sandhi ke nikt) badhte hain to ashubhta badhti jati hai. iske viprit tritiyanshon ke praranbhik nakshatron (ashvini, magha v mul) ke pratham charnon se chaturth charnon ki or sandhi se dur badhne par ashubhta kam hoti jati hai. abhukt mul men janme balak ka munh pita dvara 3 varsh tak dekhna varjit hai. islie prachin kal men aise balkon ko tyag diya jata tha. isi prakar ke do jatak age chalakar mahasant tulsidas evan kabir ke nam se amar ho gae. gandmul sangyak nakshatron ke charnanusar janmafal niche die ja rahe hain.
in falon men jahan pita, mata, jyeshth bhrata ya anuj bhrata shabd ae hain, ladkon ke lie hai aur ladkiyon ke lie inhen kurupa, shvasur, sas, jeth ya devar samjha jana chahie.