As far as the "fees" go, they are not criminal penalties, but civil penalties for one's actions. If you were stopped and arrested for a DUI, an agency has the right to bill you for the associated costs of the investigation, transportation, booking and admin fees. So if you fight a $35 ticket and you loose- you pay.
Sure. But the effective fine is still $150 or so. And that is what should be considered when asking whether the fine is "excessive" as per 8th amendment (or just plain common sense).
http://aa.usno.navy.mil/faq/docs/RST_defs.php said:
Sunrise and sunset conventionally refer to the times when the upper edge of the disk of the Sun is on the horizon, considered unobstructed relative to the location of interest. Atmospheric conditions are assumed to be average, and the location is in a level region on the Earth's surface.
Technical Definitions and Computational Details
Sunrise and sunset. For computational purposes, sunrise or sunset is defined to occur when the geometric zenith distance of center of the Sun is 90.8333 degrees. That is, the center of the Sun is geometrically 50 arcminutes below a horizontal plane. For an observer at sea level with a level, unobstructed horizon, under average atmospheric conditions, the upper limb of the Sun will then appear to be tangent to the horizon. The 50-arcminute geometric depression of the Sun's center used for the computations is obtained by adding the average apparent radius of the Sun (16 arcminutes) to the average amount of atmospheric refraction at the horizon (34 arcminutes).
Accuracy of rise/set computations. The times of rise and set phenomena cannot be precisely computed, because, in practice, the actual times depend on unpredictable atmospheric conditions that affect the amount of refraction at the horizon. Thus, even under ideal conditions (e.g., a clear sky at sea) the times computed for rise or set may be in error by a minute or more. Local topography (e.g., mountains on the horizon) and the height of the observer can affect the times of rise or set even more. It is not practical to attempt to include such effects in routine rise/set computations.
The bolded parts are why the sunset where we were is not the same as the sunset in Los Altos, which is what the ordinance references. The sign however doesn't say "park is closed 30 minutes after the sun crosses the horizon in Los Altos", nor would any reasonable person think it did. The USNO does not include any real world effects in their computations; they pretend that the earth is flat and clear.
And that's all just for the
middle of the event that normal ("reasonable") people call "sunset" and the beginning of what astronomers call "twilight". End of twilight = end of sunset in normal meaning.
Argument by simple analogy:
If you tell the wife that you'll be home by 30 minutes after the football game, the football game is 8-10, and you come home at 10:20, it's okay.
If the signs says you should be out by 30 minutes after sunset, the sunset is 5:00-6:20, and you leave by 6:45, it should be okay too.
FWIW, I think VC 38335 (headlights on half hour after sunset / before sunrise) is pretty analogous. The only definition for "sunset" in the VC is implied in VC 280:
"280. "Darkness" is any time from one-half hour after sunset to one-half hour before sunrise and any other time when visibility is not sufficient to render clearly discernible any person or vehicle on the highway at a distance of 1,000 feet."
I.e. it's implied that a half hour after sunset, there should be <1kft visibility. Which is correct by my interpretation.