Muhurta is essentially a measure of time which refers to the application of Vedic astrology wisdom in determining the auspicious time for starting an event so that it goes through in all probability smoothly and without hurdles. Simply put, it is the time we ‘elect’ (or select) to begin important events in life.
Muhurta' is a vast subject in itself but 'Chaughadia-muhurtas' provide a quick and quite effective reference table to any person who does not have access to a well-qualified Vedic astrologer or does not have time to consult him/her for any reason. You may define the 'Chaughadia-muhurtas' as general public's election astrology.
Synonyms of Chaughadia are #Chogadia, #Chaughadia, #Chaturshtika
Cho-Gadhiya means four Ghadi (4 घडी)/Ghati – (Ghadi (now used for a clock in Hindi) is an ancient measure for calculations of time in India roughly equivalent to 24 minutes. Cho-Gadhiya means four Ghadi which totals to 96 minutes. Most of Chaughadia are of approximate 96 minutes duration)
Where 1Ghati (घडी) / = 24 minutes
So 4Ghati (घडी) = 4*24 = 96 minutes
So, 96 Minutes of time in a day is known as one Chaughadia.


यमदंष्ट्रा योग

वैद्यक के अनुसार आश्विन, कार्तिक, और अगहन के लगभग का कुछ विशिष्ट काल, जिसमें रोग और मृत्यु आदि का विशेष भय रहता है और जिसमें अल्प भोजन तथा विशेष संयम आदि का विधान है। 
कुछ लोगों के मत से यह समय कार्तिक के अंतिम आठ दिनों और अगहन के आरंभिक आठ दिनों का है; और कुछ लोगों के मत से आश्विन के अंतिम आठ दिन और पूरा कार्तिक मास इसके अंतर्गत है।

यमदंष्ट्रा योग- वार और नक्षत्र के संयोग से बनता है यमदंष्ट्रा योग 
रविवार को मघा और धनिष्ठा, 
सोमवार को मूल और विशाखा, 
मंगलवार  को भरणी और कृतिका , 
बुधवार  को पुनर्वसु और रेवती ,
गुरूवार  को अश्विनी और उत्तराषाढा, 
शुक्रवार  को रोहिणी और अनुराधा , 

शनिवार को श्रवण और धनिष्ठा नक्षत्र होने पर अत्यंत पीड़ादायक योग यमदंष्ट्रा योग बनता है  

Choosing best Muhurta for Timing of Surgery: Genral Rules To Ponder

Vedanga Jyotisha refers to a specific unit of time commonly known as Muhurta Jyotisha. Muhurta signifies the most benefic period when there is maximum harmony between stellar aspects (planets/stars) and the concerned human being or circumstances. It is that period which helps in concentrating the energy of the planets and other astrological factors in an auspicious way so as to void the evil powers and make the result of the work performed most fruitful. It is not only the positive time to initiate an event so that, not only it is carried out without any hurdle, but it also provides best results. 
Muhurta for Surgery or treatment:
As it is said "Well begin is half done" so any work started in auspicious time adds to success.
In the Brāhmaṇas, muhurta means a division of time: one-thirtieth of a day, or a period of two Ghati (48 minutes). Further each muhūrta is further divided into 30 (Indian minutes) or kalā (making 30 Kalā ≈ 48 western min). Each kalā is further divided into 30 (Indian) seconds or Kāṣṭhā, making 30 Kāṣṭhā ≈ 1.6 western minute.



These guidelines are also those to be followed any time a “king” enters his house after returning from a journey.
Ayana: If possible, Uttarayana is preferred.

माघ-फाल्गुन-वैसाख-ज्येष्ठ-मासेषु शोभना:|
प्रवेशो मध्यमो ज्ञेय: सौम्य (मार्गः ) कार्तिक मासयो: || (here months are Lunar Months )

Masa: Vaisakha, Jyeshtha, Magha and Phalguna are most favorable. Kartika and Margasira are middling. Chaitra should be avoided.

Nakshtra: Rohini, Mrigshira, Uttara Phalguni, Anuradha, Uttarashadha, Uttara Bhadrapada, Chitra and Revati are best.

Kalaprakasika also considers Punar vasu, Pushya, Hasta, Shravana and Shatbhisha as favorable, while Muhurta Chintamani also considers Chitra as favorable, these all of which may be considered as middling.

Amongst the favorable Nakshtras mentioned, it is yet more favorable if the Nakshtra faces the door of the house.


Godhuli Lagna

While searching for an auspicious Muhurta Godhuli Lagna comes first to mind. This is considered one of the best Muhurta as all the defects are neglected in this lagna. In this lagna the nakshatra, tithi, karana, day, navamsha, muhurat, yogas, planets in the eighth house, jamitra dosh etc are not taken into consideration while calculating Godhuli Lagna. In, this lagna the Moon is situated in the second, third and eleventh house. All these situations are considered auspicious as well.

Bit Moon and Mars should not be present in the lagna of Godhuli Muhurat. Moon in the sixth house and Mars in the seventh house should also be sacrificed. The eighth house from this lagna should also be empty. 

The seventh sign from the ascendant sign at the time of sunrise is known as Godhuli lagna. Godhuli literally means 'the auspicious time when the dust is raised by cows'

गोपैर्यष्ट्याहतानं खुरपुटदलिता यातु धूलिर्द्दिनान्ते।
सोद्वाहे सुन्दरीराणं विपुलधनसुतारोग्य सौभाग्यकर्त्री॥13॥
तस्मिन काले न चर्क्षं न च तिथिकरणं नैव लग्नं न योगः।
ख्यातः पुंसां सुखार्त्थं शमयति दुरितान्युत्थितं गोरजश्च॥14॥


1 Muhurta for Swearing in Ceremony Panchang and Muhurta #Godhuli_Lagna 21 great evils / Ekavimsati Mahadoshas / 21 koota Abhijit Muhurta – powerful and auspicious time of the day Ayana - Its astronomical and astrological Importance Bhadra and its Importance in Muhurta Bhadra and its importence in muhurta Bhdra Brahma Muhurta CHAUGHADIA MUHURTA CONSEQUENCES OF AN INAUSPICIOUS MUHURTA Calculation of Rahu Kaal in Muhurta Chapter I. The Importance of Muhurtha Classification Of Tithis Classification of Nakshatras Classification of Tithi Components of Panchang - Tithi Days of the Week -Vara Fixed Costellations &Their Usefulness in Muhurta GUIDELINES FOR SPECIFIC MUHURTAS Gandaanta / गण्डान्त - Ending Joint Godhuli Muhurta HOUSE/BUILDINGS- ENTERING A NEW HOUSE (GRIHA PRAVESA) Importance of Lagna in Muhurta Importence of Eclipse In Muhurta Astrology Jaya Kalash Shuddhi Manglik Dosha - Kuja Dosha Moveable Nakshtras and Their Usefulness in Muhurta Muhuratha - General Hints Muhurta (Electional Astrology) B. V. Raman Muhurta (Electional Astrology) B. V. Raman - Chapter III Muhurta (Electional Astrology) B. V. Raman - Chapter IV Muhurta (Electional Astrology) B. V. Raman - Chapter IX Muhurta (Electional Astrology) B. V. Raman - Chapter V Muhurta (Electional Astrology) B. V. Raman - Chapter VI Muhurta (Electional Astrology) B. V. Raman - Chapter VII Muhurta (Electional Astrology) B. V. Raman - Chapter VIII Muhurta (Electional Astrology) B. V. Raman - Chapter XI Muhurta (Electional Astrology) B. V. Raman - Chapter XII Muhurta (Electional Astrology) B. V. Raman - Chapter XIII Muhurta (Electional Astrology) B. V. Raman - Chapter XIV Muhurta (Electional Astrology) B. V. Raman - Chapter XV Muhurta (Electional Astrology) B. V. Raman - Chapter XVI Muhurta (Electional Astrology) B. V. Raman - Chapter XVII Muhurta (Electional Astrology) B. V. Raman - Chapter XVIII Muhurta (Electional Astrology) B. V. Raman -Chapter X Muhurta and its Importance Muhurta for Surgery Muhurta in Vedic Astrology Nakshtra Vishanadi or Visha Ghati Nanda Panchaka - Five Source energy Panchanga Shudhi Panchanga yoga Pre-Natal Ceremonies Purna Tithi Rikta Selective Use of Hora Table Shunya Tithi – Shunya Nakshtra – Shunya Lagna Tarabala and Chandrabala in Muhurta Three and half Muhurta in Year Tithi Its Lordship and Energy Tripapa Chakra Type of Marriages In Vedic Culture Types of Tithi USE OF TITHI IN MUHURATHA Vara and suitable activities related to muhurta Vara-Nakshtra-Tithi yoga Vishhutashan yoga Vishkanya yog Vyatipata & Vaidhriti muhurath Chapter IV Influence of Constellations muhurta to start Medicine. अंक विज्ञान में तिथि का महत्त्व गंडांत यमदंष्ट्रा