Light Collection Effectiveness Calculator

An easy way of comparing apples to apples

The Licolef Calculator is a convenient way to compare 2 telescope setups with each other.
By filling in a few key variables the calculator will give you the (PAF)^2 value per setup. This value stands for the "Light Collection Effectiveness" of the setup. The higher the number, the more light your sensor will receive per pixel. And more light means a better signal-to-noise ratio and thus less required exposures (subs) to aquire the same results. By reducing the individual variables to a single number it becomes possible to quantifiable compare two setups and assist you in making decisions.

Terminology

Aperture:

• Main diameter or F# value; fill in your aperture diameter, if unknown fill in the F# value of your lens
• Central obstruction diameter; the diameter of the central obstruction blocking your lightpath, like a secondary mirror or corrector/collector. Leave empty if not applicable
• Projected image circle; The light circle your lens projects onto your camera sensor, leave empty if unknown
• Amount of reflecting surfaces; Total amount of mirrors in the optical path
• Amount of lens elements; Total amount of lenses in the optical path

Focalpoint:

• Focal length; the focal distance of your lens/telescope
• Reducer/Teleconverter/Barlow; Fill in the X magnification or X reduction, 1x if unaltered

Sensor:

• Sensor width and height; speaks for itself 🤭

Results:

• Light Collection Effectiveness in (PAF)^2 which is a measurement of your setup's capability of collecting light expressed in a (pixel.aperture.focal)-ratio
• larger value is better
• Telescope A vs B; a handy comparison between your two setups and their light effectiveness resulting in the difference in amount of required sub-exposure time
• the larger value is the better setup, the difference in amount of required sub-exposure time for equal SNR is inversely proportioned

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