heliacal

And the heliacal risings of Jupiter, as also, indeed, those of the other planets, are shown in almanacs for astrological purposes.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" by Various

The Egyptians had, at an early period, observed that the rising of the Nile coincided with the heliacal rising of Sirius, the Dog-star, and hence they very plausibly referred it to celestial agencies.

From History of the Intellectual Development of Europe, Volume I (of 2) Revised Edition by John William Draper

If therefore Ilioneus, according to our supposition, understand the heliacal rising of Orion, Anna must mean the achronical, which the different epithets given to that constellation seem to manifest.

From Discourses on Satire and on Epic Poetry by John Dryden

It seems to have been considered of great importance in ancient Egypt, as its heliacal rising announced that of Sirius, which heralded the annual rising of the Nile.

From Astronomical Curiosities Facts and Fallacies by J. Ellard Gore

Either the calendar did not originate in Egypt, or it was introduced in 2780 B.C., when again the heliacal rising Sothis fell on the first of Thoth.

From The Egyptian Conception of Immortality by George Andrew Reisner