Upasththanam
Although Keralites popularly refer to mid-day worship as Upasththaanam, in the vedic parlance, Upasththanam merely refers to prayers facing the Sun God.

Those who have to observe Jalapraasanam, do that after the necessary feet ablutions (Kaalu kazhukal) and Aachamanam.

Manthram: Om.

"Aapa: punanthu pritthiveem pritthvi poothaa punaathu maam Punanthu brahmanaspathi: brahmapoothaa punaathu maam Yaduchhishtamabhojyam yad yadvaa duscharitham mama Sarvam punanthu maamaapo asathaancha prathigrahaswaahaa"

Wash the feet, and do Aachamanam and Prokshanam again.

Facing east, perform Arghyadaanam once reciting Gaayathri Manthram. Wash the hands.

At the water source or pond, step up from water and recite Gaayathri ten times omitting Chchandas in the beginning. Recite Gaayathri again and perform Arghyadaanam once more.

Moisten hands, hold on to the earlobes and recite the Upasththaana Manthram facing the sun. (Some people keep the little and ring fingers as well as the thumb together; some hold all fingers and thumb together.)

Note: Till repeated Arghyadaanam, the rituals of all three Vedic clans are the same though the Upasththaanams can differ as follows.

Upasththaana Manthrams

For Rigvedis

Om.	1.	Aa krishnena rajasaa varthamaano nivesayannamritham marthyancha Hiranyayena savithaa raththena aa devo yaathi bhuvanaani pasyan
	2.	Thath chakshur devahiyham (purasthaal) sukramucharal Pasyema saradassatham jeevema saradassatham

Wash hands, take water in cupped hand, turn clockwise, sit down and perform Devatharppanam, Rishi tharppanam and Pitrutharppanam. Wash feet, do Aachamanam and come away.

(Note: Some don’t voice the first Rik (stanza). Many don’t include the word "purasthaal" in the second Rik.)

For Yajurvedis

Om.	1.	Udvayanthamasaspari pasyntho jyothirutharam Devam devathraa sooryamaganma jyothruthamam
	2.	Uduthyanjaathavedasam devam vahanthi kethava: Drise visvaaya sooryam
	3.	Chithram devaanaa mudagaadaneekam chakshur mithrasya varunasyaagne: Aa praa dyaavaa pritthivee anthareeksham soorya aathmaa jagathasthastthushascha
	4.	Thachakshur devahitham purasthaal sukramucharal Pasyema saradassatham jeevema saradassatham Bhavaama saradassatham srunavaama saradassatham Prabravaama saradassatham ajithaasyaama saradassatham Jyokcha sooryandrse
	5.	Ya udagaal mahathornavaal vibhraajamaana: sarirasya madhyaal Sa maa vrikshabho lohithaaksha: sooryo vipaschinmanasaa punaathu

Variations for Yajurvedis
Some Baudhaayanans do not hold on to the earlobes while reciting the above Manthrams. Rather, they take water in both hands and recite the Manthrams from "Udvayantha…" to "…sukramucharal" of the fourth Manthram and then sprinkle the water in the cupped hands on to their faces. Then they hold on to the ear lobes and recite the rest of the Manthram from "pasyema…" in the fourth to the very end of the fifth. Then they fold their hands in prayer and recite "Om. grini: soorya aadithyah:". Taking water in the hands again they recite: "Om. Aapojyothirasomritham. Brahma: bhoorbhuvasva: Om. and then perform all three tharppanams for deva, rishi and pitr. Then they set the thread properly rightwards, perform Aachamanam and come away.

For Saamavedis
Hold onto the ear lobes and recite:

Om.	1.	Uduthyam jaathavedasam devam vahanthi kethava: Drisye visvaaya sooryam
	2.	Chithrandevaana mridagaadaneekam chakshur mithrasya varunasyaagne: Aa praa dyaavaapritthivee anthareeksham soorya aathmaa jagathasthastthushascha
	3.	Aadithya wwukra udagaal purasthaal jyothi: krinvanvithamo baadhamaana: Aabhaasamaanaph pradisonu sarvaa: bhadrasya karthaa ruchayanna aagaal

Then, propitiate the Sun, and perform all three tharppanams for deva, rishi and pitr. Finally adjust the sacred thread properly rightwards, wash the feet and come away.

All clans must do all tharppanams after Maadhyamdinam.