5/21/2023 0 Comments Hours until sunsetThe degree to which overexposure can occur varies because different types of film and digital cameras have different dynamic ranges. In the middle of the day, the bright overhead sun can create strong highlights and dark shadows. For a location sufficiently far from the equator, the sun may not reach an altitude of 10°, and the golden hour lasts for the entire day in certain seasons. ![]() For a location closer to the Equator, the same altitude is reached in less than an hour, and for a location farther from the equator, the altitude is reached in more than one hour. In Los Angeles, California, at an hour after sunrise or an hour before sunset, the sun has an altitude of about 10–12°. The character of the lighting is determined by the sun's altitude, and the time for the sun to move from the horizon to a specified altitude depends on a location's latitude and the time of year. The term hour is used figuratively the effect has no clearly defined duration and varies according to season and latitude. In addition, the sun's low angle above the horizon produces longer shadows. More blue light is scattered, so if the sun is present, its light appears more reddish. This is technically a type of lighting diffusion. When the sun is low above the horizon, sunlight rays must penetrate the atmosphere for a greater distance, reducing the intensity of the direct light, so that more of the illumination comes from indirect light from the sky, reducing the lighting ratio. The color temperature can also change significantly with altitude, latitude, season, and weather conditions. It tends to be around 2,000 K shortly after sunrise or before sunset, around 3,500 K during "golden hour", and around 5,500 K at midday. Or, if you don't know, at least test the code and see what rule it is applying, so you can document that.The color temperature of daylight varies with the time of day. ![]() Does that mean you want your program to stay on all month? Or that you want to pick an arbitrary time to start up and shut down (e.g., start 2 hours before "midnight" and end an hour after)? Whatever rule you come up with, I think ephem has enough data for you to write it. What if you go even farther north than Oulo? For example, in Rovaniemi, in early of June, the next sunset is a month away. In that case, you only need to check sunrise, you're in case 1 or 3 just check sunrise-2H otherwise, you're in case 2, just check sunset-1H. The moment the sun rises, my logic seems to fail because after that point it starts computing the sunrise for tomorrow. Return ((next_sunrise - sunrise_shift) < now) Return (now < (next_sunset - sunset_shift)) Next_sunset = ephem.localtime(here.next_setting(ephem.Sun())) Next_sunrise = ephem.localtime(here.next_rising(ephem.Sun())) # Choose when to start and stop relative to sunrise and sunsetĪssumes sunset NEVER comes after midnight # Choose your location for sunrise/sunset calculations Return ((sunrise - now) < sunrise_shift) and ((sunset - now) < sunset_shift)Įdit: Updated after reading solution # Dependencies # Return whether it is some amount of time before sunrise AND sunset Sunset_shift = datetime.timedelta(hours=END_BEFORE_SUNSET_HR) Sunrise_shift = datetime.timedelta(hours=START_BEFORE_SUNSRISE_HR) Sunset = ephem.localtime(here.next_setting(ephem.Sun)) Sunrise = ephem.localtime(here.next_rising(ephem.Sun)) Mode is shifted earlier to begin before sunrise and end before sunset. Returns whether we should operate in the 'daytime' mode. ![]() If I continuously check using next_rising() and next_setting(), the moment the sun rises, my logic seems to fail because after that point it starts computing the sunrise for tomorrow. I want to be 'on' 2hours before daylight up until 1 hour before sunset. I'm checking time about every minute, but don't have a good way to check whether I'm in this 'on' mode of operation.
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