Localization of Vinland
A lot of authors have stated there point of view about the localization of Vinland based upon the sagas and Leif's comments.
Thorsteinn Vilhjalmsson writes in: Time and Travel in Old Norse Society, URL: www.raunvis.hi.is\~thv\t_t.html
So much for the "ßtt" for the moment. As to the time division of "eykt/octant" we may just state that the saga literature abounds with references to the individual octant divisions of the day as described above. When we would have stated the hour of an event the sagas simply state the octant instead, sometimes using, e.g., half an octant when such a precision is needed.
When we come to the relation of the octant marks and the sun the most famous quotation is again from the GrŠnlendinga saga. When describing the circumstances in "VÝnland" (Wineland or The Land of Vine, i.e. some place on the eastern coast of North America) one of the observations goes as follows:
Meira var ■ar jafndŠgri en ß GrŠnlandi ea ═slandi. Sˇl hafi ■ar eyktarsta og dagmßlssta um skammdegi.(18)
In this country, night and day were of more even length than in either Greenland or Iceland.
The sun passed the points of "eykt" and "day mark" in the period of the shortest days.(19)
In modern language the most straightforward interpretation of this implies that the sun would pass the horizon points of Southeast and Southwest (20) in the shortest day of the year. You may also note that the author clearly finds this worthwhile to report.
My own computer simulation based on these comments gives us a latitude around 48 degrees north even if we use the definition of "eyktar-stad" from the old Icelandic law book: "Kristnirettr".
Eyktarstadr occur around 4 pm at 48 dg N (Vinland, wintersolstice). For comparing reasons eyktarstadr in Trelleborg, Denmark (55 dg N) will be around 3 pm at wintersolstice, and in Greenland (60 dg N) it will be around 2 pm.
Check nomogram here.