In VIEWFINDR we offer planning tools and weather for astrophotography. Calculate exact cloud distances for astrophotography. Conventional weather apps only calculate cloud cover at one location, with VIEWFINDR you can plan clouds in 3D, for targets that are not only at the zenith.
The parameter is divided into the three cloud levels:
For exact planning of the clouds you always have to check all cloud levels! The main use of the parameter is to plan a cloud-free sky, for example to plan the weather for astrophotography. This also includes photography of the moon. Another use is the planning of a cloud-free sunrise or sunset.
Conventional weather apps only calculate the clouds at one location and do not look at the sky three-dimensionally. This creates the problem that there may be no clouds at your location, but clouds are located exactly on the horizon where the moon rises, the sun sets, or the Milky Way would be in the sky.
For this purpose, three red circles (the placement tool) are displayed. These change their diameter together with the selection of the clouds (Low, Medium or High). This tool can be used to determine whether there is enough distance between the clouds at a photo spot so that the sky is free of clouds for astrophotography.
If all clouds are outside the outermost 2° circle, the sky at your location will be completely free of clouds. For the inner 10° circle, there may still be some clouds near the horizon. You must always check all three cloud maps!
This parameter shows the cloud cover between 0% and 100%. The parameter is divided into low, medium-high and high clouds. These each correspond to certain height ranges, which can be taken from the figure. Cloud forecasts are used to plan weather for astrophotography, cloud-free sunrises or alpenglow.
If a time is selected, the colour overlay loads. Loading is indicated by a small loading symbol at the bottom right of the map. If there are no clouds in a region, the map remains empty. The denser the white colour overlay is at a location, the denser the sky is covered with clouds at that location.
With the help of the scale, the colour overlay can be translated into a numerical value and thus determine how high the degree of cloud cover is at a location.
In order to be able to see the cloud forecast clearly, it is advisable to use the background map “Satellite”. The background map can be changed on the corresponding symbol. In addition to the weather for astrophotography, a suitable location in a clearing can also be found on the “Satellite” background map.
The degree of coverage indicates what percentage of the sky is blue and what percentage is grey. With an opacity of 50%, this means that 50% of the sky is covered by solid clouds. The other 50%, however, is clear blue sky.
It does not mean that the sky is covered with a single layer of clouds, 50% of which are transparent. In the example photo shown, a coverage of about 50% can be seen. There are equal amounts of blue and cloudy parts of the sky.
To predict the weather for astrophotography, the degree of cloud cover is particularly valuable, because it can be used to estimate what percentage of the night a cloud will cover the desired target. The higher the cloud cover, the less integration time is left.
This is a forecast generated by computer calculations, therefore there will always be deviations. The clouds will not appear exactly as the forecast indicates. The forecast is more precise for large, continuous cloud fronts than for small, local cloud fields.
Therefore, there will be deviations of a few kilometres. This deviation is not noticeable for large cloud fronts, but it is for local cloud fields. Therefore, the forecast for large cloud fronts is always somewhat more accurate.
We have developed a placement tool so that you are not suddenly surprised by clouds in the compass direction of your target during your astrophotography. The concentric circles in VIEWFINDR are automatically adjusted to the selected cloud height and guarantee that the clouds of the respective height level will be below (10°,5°,2°) above the horizon. To use the tool you need to set a rough map scale, zoom out on the map until you can see the three circles. Change the time and see if the clouds are getting too close to your target in a certain direction.
To check whether the sun is visible at sunrise or sunset and is not covered by clouds, you must use the placement tool. With the help of this tool, check all height levels of the clouds to see if the clouds remain below 2° on the horizon. To do this, the clouds in the direction of sunrise and sunset must lie outside the 2° circle of the placement tool. To do this, additionally activate the direction tool for sunrise and sunset. Use the time of sunrise or sunset as the time of day.
Activate the positioning tool for clouds, together with the direction tool for sunrise and sunset. Move the centre of the screen to the desired mountain. Zoom out of the map until you can fully see the three circles of the positioning tool. For alpenglow to be possible, the clouds in the direction of sunrise or sunset must remain below the 2° mark. Check this, for all three height levels of the clouds. If the condition is met, the mountain will be illuminated if the local orography allows it.
The weather forecast in VIEWFINDR is a computer simulation that very realistically forecasts the coming weather. However, the forecast is not exactly the reality and there will be deviations.
In VIEWFINDR new weather data is provided every 3h. For example, if you check for the probability of afterglow after sunset in the morning hours, the forecast will change several times over day. This is perfectly normal and that’s a good thing!
The closer the deadline, i.e. the sunset in the evening, the smaller the deviation of the computer simulation from reality becomes. The forecast becomes more precise. Before you finally set out to take pictures, you should therefore take another look at the current forecast.
You should therefore check the forecast again before you start your photography tour to see, if the probability is still high. Don’t be mad if the forecast probability changed into worse, it probably saved you from a bad outcome!
The weather forecast in VIEWFINDR is limited to 24h for local weather models and 72h for continental weather models. It is not useful to look into the future for a longer period. The forecast becomes inaccurate and is not reliable. Weather apps that allow forecasts of more than 3 days but do not provide any indication that the forecast is extremely inaccurate are a disgrace. This gives the
Just as the resolution of your camera is limited, i.e. it cannot take an “infinitely” sharp photo, the resolution of the weather model is also limited. This is 2.8km for Central European weather data and 7km for European weather data.
Structures and features of the landscape that are not that large are averaged by the model. For example, if a mountain is 800m high, and the valley next to it is 400m high, then the landscape for the weather model in that “pixel” is 600m high, corresponding to the average altitude.
This means that small structures, like narrow mountain valleys or local small river valleys cannot be properly captured by the model. This is not a problem, you just have to learn to deal with it. If a valley in the mountains is much smaller than the resolution of our weather model, then you have to interpolate.
Small valleys always end in larger valleys. You can therefore use the weather in the next larger valley as a good reference for the weather in a smaller, adjacent valley. In the example, you can see that the large valley is filled with fog. It is almost certain that the small valley is also filled with fog.
Due to the limited resolution, it makes sense not to use too much zoom. It is important that you look at the overall context. Therefore, consider the weather forecast not only for your location, but at least for the entire region where you are shooting.
This example show how the weather model sees the landscape. It is pixelated because of the limited resolution.
Due to limited resolution, this layer of low clouds/fog will not indicate fog in valleys with a size below the resolution.