"in the zenith" is correct and usable in written English.
You could use it to indicate a moment of peak activity or prominence, for example: “The young actor's career had reached its zenith.”.
We describe our experiences of strut failure in the Zenith abdominal aneurysm endograft device.
Over in the Zenith suite, on the largest TV set, a woman singing turned into an old Shirley Temple movie.
Figure 1a shows the incident solar spectrum and atmospheric transmission in the zenith direction as a function of wavelength30.
Don Blankenship could be on his way to becoming a study in how anti-establishment politics can backfire, even in the zenith of anti-establishment politics.
Slowly paced the bright, bright orb up the eastern sky; long it lingered in the zenith, and still more slowly wandered down the west: it touched the horizon's verge--it was lost!
The plot also shows the angular atmospheric transmittance at a representative wavelength of 10.5 µm estimated using τatm = τ01/cosθ 10, where θ represents the zenith angle and τ0 represents the atmospheric transmittance in the zenith direction.
Shrinkage at 12 months correlated with frequency of endoleak in the device groups, and was most common in the two Zenith groups (54% ± 7.3% in the Zenith-MCT group and 56% ± 7.8% in the Zenith-SIT group) and the Talent group (52% ± 9.7%) and was least in the Excluder group (15% ± 7.9% at 12 months, P <.001).
Results: While overall survival was diminished in the Zenith-SIT group (P =.046), risk for aneurysm-related death was similar in all groups (P =.336), averaging 2% or less at 12 months.
By contrast, sac growth occurred most often in the Zenith-SIT group (13% ± 4.5% at 12 months, P =.034), possibly as a result of the challenging aortoiliac anatomy frequently present in these patients.
Al Unser Jr.'s victory in Indianapolis in 1994 marked the zenith of the team.
For a person in the northern hemisphere, the zenith position in the southern hemisphere seems to be "down".
