One of the possible readings of tagata rogo is 'the man who is announcing' (N. Zeal., rongo, to hear, to sound, report, news.). The position at Cursa suggests an announcement regarding Orion and Auriga:

 

The message could be to say that the old year (the prededing Sun king) had 'gone down to the fishes' (was dead).

We should remember the Chinese custom of announcing the end of the old year:

... In China, every year about the beginning of April, certain officials called Sz'hüen used of old to go about the country armed with wooden clappers. Their business was to summon the people and command them to put out every fire. This was the beginning of the season called Han-shih-tsieh, or 'eating of cold food'. For three days all household fires remained extinct as a preparation for the solemn renewal of the fire, which took place on the fifth or sixth day after the winter solstice [Sic!]. The ceremony was performed with great pomp by the same officials who procured the new fire from heaven by reflecting the sun's rays either from a metal mirror or from a crystal on dry moss. Fire thus obtained is called by the Chinese heavenly fire and its use is enjoined in sacrifices: whereas fire elicited by the friction of wood is termed by them earthly fire, and its use is prescribed for cooking and other domestic purposes ...

... Like archaic China and certain Amero-Indian societies, Europe, until quite recently, celebrated a rite involving the extinguishing and renewal of domestic fires, preceded by fasting and the use of the instruments of darkness. This series of events took place just before Easter, so that the 'darkness' which prevailed in the church during the service of the same name (Tenebrae), could symbolize both the extinguishing of domestic fires and the darkness which covered the earth at the moment of Christ's death. In all Catholic countries it was customary to extinguish the lights in the churches on Easter Eve and then make a new fire sometimes with flint or with the help of a burning-glass. Frazer brings together numerous instances which show that this fire was used to give every house new fire. He quotes a sixteenth-century Latin poem in a contemporary English translation, from which I take the following significant lines: On Easter Eve the fire all is quencht in every place, // And fresh againe from out the flint is fecht with solemne grace. Then Clappers cease, and belles are set againe at libertée, // And herewithall the hungrie times of fasting ended bée ...

... The reader will no doubt have noticed that a curious analogy exists between the means employed for the tapped-out call in the South American myths: a resonator made from a gourd of tree-trunk which is struck, sticks which are knocked against each other, or clappers, and a liturgical complex belonging to the Old World, known as the instruments of darkness. The origin of these instruments, and their use from the Thursday to the Saturday of Holy Week, presents a great many problems. As I cannot claim to participate in a complex discussion which lies outside my competence, I shall merely refer to one or two generally accepted points. It would seem that fixed bells in churches did not make their appearance until rather late, about the seventh century. Their enforced silence from the Thursday to the Saturday of Holy Week does not seem to be recorded before about the eighth century (and then only in Rome). At the end of the twelfth and beginning of the thirteenth century, the restriction appears to have spread to other European countries. But the reason for the bells remaining silent, and for them being replaced temporarily by other sources of noise, is not clear. Their alleged journey to Rome, which accounted for their temporary absence, may be no more than an a posteriori explanation, founded moreover on all kinds of beliefs and imaginative suppositions connected with bells: they were thought to be animate, vocal beings, capabe of feeling and acting, and fit for baptism. In addition to summoning the congregation to the church, bells had a meteorological, and even a cosmic, function. Their reverberations drove storms away, dispelled clouds and hail, and destroyed evil spells ...

... [E:87-90] On the thirtieth day of the month of October ('Tangaroa Uri'), Hotu asked about the stone figure (moai maea) named Oto Uta [te moai.maea.ko oto uta.te ingoa]. Hotu said to Teke [he ki.kia Teke.a Hotu], 'Where is the figure Oto Uta (corrected in the manuscript for Hina Riru)?' Teke thought about the question [he hakatopa.a Teke. i roto a ia.i te ki] and then said to Hotu [he kī. kia Hotu.a Teke], 'It was left out in the bay.' [i mua i te hanga ana i re(h)u ro ia.] Hotu said [he ki a Hotu] to Pure O [Ō], to Pure Ki, and to Pure Vanangananga: 'You fellows (kope), sail [ko oho.korua ko nga kope] to the friend (hoou), to Oto Uta. Bring him here [ka too mai], he who is resting out there in the bay [i mua.i te hanga]. Move him carefully (? nee), you fellows, so that the king, that Oto Uta is not damaged!' [o kori a i te ariki.i a oto uta.] [Pure Ō, Pure ki, and Pure vananganaga left (land behind), (they) launched the canoe and sailed to Hiva,] The canoe of Pure O left [i oho.ai] on the fifth day of November ('Ruti'). After the canoe of Pure O had sailed [i oho.era te vaka.o Pure ō.] and had anchored [tomo = to make landfall] out in the bay [i tomo era.ki mua ki te hanga], in Hanga Moria One [ki hanga moria one], Pure saw the figure [he ui a Pure ō.ko te moai], which had been lying there all this time [e moe no ana], and said to his younger brothers (ngaio taina), 'Let's go my friends (hoa), let's break the neck [hahati atu te ngao] of this mean one (or, ugly one, rakerake). Why should we return [ki he.a.tatou i hoki atu ai] to that fragment of earth (te pito o te kainga), i.e. Easter Island? Let us stay in our (home)land!' [he noho ro ai tatou i to tatou kainga.]  After the canoe of Pure O had departed [i oho.era te vaka o Pure ō.] ... Pure O picked up a large round stone (pureva) and hit the top of the figure. Because of the stone, the neck of Oto Uta was broken. Then the wind started blowing, the billow rose, the waves broke, the rain started falling, the flame (i.e., lightning) shone brightly, and the thunder rolled. As soon as the wind started blowing, the waves broke, the rain fell, and thunder rolled, King Hotu knew that Pure O had done harm to Oto Uta. Hotu spoke: 'These fellows have done a mean thing to King Oto Uta!' Hotu spoke, 'These fellows have done a mean thing [ku kori ana tau ngaio era] to King Oto Uta!' After the neck of Oto Uta had been broken, Kuihi and Kuaha arrived. They picked up the neck of King Oto Uta, took it, and brought it with them. They arrived out in the bay [he tuu ki mua ki te hanga], in Hanga Rau. (There) Kuihi and Kuaha left (the fragment). They arrived out in the bay [he tuu ki mua ki te hanga], in Hanga Rau. (There) Kuihi and Kuaha left (the fragment). Kuihi and Kuaha arrived [he tuu a kuihi.a kuaha] and told the king the following, 'King Oto Uta is out in the bay of Hanga Rau.' Hotu said [he ki a Hotu] to his servant (tuura) Moa Kehu, 'Go down to King Oto Uta and take him up out of the bay of Hanga Rau!' Moa Kehu arose [he ea a Moa kehu], went down, picked up (the fragment), and carried (it) on his shoulders to the house [to the front of the house, ki mua ki te hare]. There he left it for king Hotu [he hakarere ki te ariki.kia Hotu]. King Hotu sat down [he noho te arik(i).a Hotu] and wept [he tangi] over King Oto Uta. This is [penei] Hotu's lament (tanginga):

ka hati toou ngao e oto uta.e te ariki ē.mo tau papa rangaranga o haho i te tai.mo tuu huehue rangaranga o haho i te tai.mo tau hahave rere a- i ka pae.mo tuu ngū rere ai ka paē.mo te ika aringa riva nei he aku renga.ai ka paē.	ka hati toou ngao e oto uta e te arike e	Broken is your neck, oh Oto Uta, oh king!
	mo tau papa rangaranga o haho i te tai	Floating (?) like a raft (?) out at sea.
	mo tuu huehue rangaranga o haho i te tai	To be erected for the drifting huehue (fish) out at sea.
	mo tau hahave rere ai ka pae mo tau ngu rere ai ka pae mo te ika aringa riva nei he aku renga ai ka pae	Able (?) to put an end to the flight of the flying fish hahave; Able (?) to put an end to the flight of the flying fish ngu; Put an end to this fish, a dorado, with the good face!

And then there was the remarkable incident at the island of Paxi,

- when in the evening the wind had dropped to a stand-still as if indicating a solstice:

... The father of Aemilianus the orator, to whom some of you have listened, was Epitherses, who lived in our town and was my teacher in grammar. He said that once upon a time in making a voyage to Italy he embarked on a ship carrying freight and many passengers. It was already evening when, near the Echinades Islands, the wind dropped and the ship drifted near Paxi. Almost everybody was awake, and a good many had not finished theire after-dinner wine. Suddenly, from the island of Paxi was heard the voice of someone loudly calling Thamus, so that all were amazed. Thamus was an Egyptian pilot, not known by name to many on board. Twice he was called and made no reply, but the third time he answered; and the caller, raising his voice, said, 'When you come opposite to Palodes, announce that Great Pan is dead.' 

On hearing this, all, said Epitherses, were astounded and reasoned among themselves whether it were better to carry out the order or to refuse to meddle and let the matter go. Under the circumstances Thamus made up his mind that if there should be a breeze, he would sail past and keep quiet, but with no wind and a smooth sea about the place he would announce what he had heard. So, when he came opposite Palodes, and there was neither wind nor wave, Thamus from the stern, looking toward the land, said the words as he heard them: 'Great Pan is dead'. Even before he had finished there was a great cry of lamentation, not of one person, but of many, mingled with exclamations of amazement. As many persons were on the vessel, the story was soon spread abroad in Rome, and Thamus was sent for by Tiberius Caesar. Tiberius became so convinced of the truth of the story that he caused an inquiry and investigation to be made about Pan; and the scholars, who were numerous at his court, conjectured that he was the son born of Hermes and Penelope ...

From all this we should be somewhat better equipped to look at the beginning of the 4th (unlucky) line following tagata rogo. For here there were people announcing a new king (e gagata ariki):