![]() ![]() While you can also use film cameras to photograph eclipses, this article specifically discusses digital camera use. No matter what kind of camera you own, there are a variety of techniques that you can use to photograph a lunar eclipse: wide-angle, telephoto, multiple exposure and star trail. If you're away from city lights, the Milky Way becomes bright and beautiful as the total phase begins. The crescent of the moon grows thinner as darkness propagates through a night sky now deprived of moonlight. If the eclipse is a total one, the last remaining minutes of the partial phases can be quite dramatic. During the next hour, the moon gradually dips deeper into Earth's dark umbral shadow. These are easy to see as well, with the unaided eye.Ī lunar eclipse begins as a small notch slowly appears along one edge of the moon. During the total phase (totality), the moon turns a vibrant red color. This occurs when the entire moon passes through the Earth’s umbral shadow. These eclipses are easy to see with the unaided eye. This occurs when a portion of the moon passes through the Earth’s umbral shadow. These eclipses are subtle and hard to observe. This occurs when the moon passes through the Earth’s penumbral shadow. There are two or more lunar eclipses a year. For detailed information, please refer to the Weather Radar Image website.A lunar eclipse occurs whenever the moon passes through the Earth’s dark shadow, which can only happen during a full moon. The Hong Kong Observatory's radar images closest to the time of tropical cyclone analysed position can be shown by pressing the 'Radar Image' button, below which is the 'Time of image' representing the time when radar completes its scan.Since it takes time to receive and process the satellite data as well as generate the image, the time of image may somtimes be different from the time of tropical cyclone analysed position. The infra-red satellite image closest to the time of tropical cyclone analysed position can be shown by pressing the 'Satellite Image' button, below which is the 'Time of image' representing the time when satellite data is completely received at the ground reception system.These departures are partly due to uncertainties in locating the centre of the tropical cyclone, and partly due to actual short-term variations in the direction and speed of movement of the tropical cyclone itself. Short-term erratic departure of the tropical cyclone from the general direction of movement may occur from time to time.The corresponding radius of 'Potential Track Area' is determined from the statistics in the past years as the mean value. Such real-time positions could deviate from those obtained later through "Best Track Analysis" when more comprehensive sets of observations become available. *Analysed position refers to the positions of tropical cyclones fixed by the Observatory based on observation data available in real time. The size in terms of radius of the 'Potential Track Area' corresponding to different forecast hours are determined from the error statistics of the forecasts issued in past years (updated in 2022) and are as shown in the following table: It will be particularly larger beyond 72 hours and is indicated with lighter shadings on the map. ![]() The area grows as the forecast hour increases. ![]() Literally, it means that among 10 times of track forecast for similar situations, the tropical cyclone will be centred within the indicated area in about 7 times. By pressing the 'Potential Track Area' button, the probable area within which the tropical cyclone will fall with a probability of 70% will be shown.
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