Before SKW can be used at least one instrument must be set.

At the minimum one needs to provide:

  • A name for the setting.
  • The focal length, the aperture and central obstruction, relative to the scope aperture diameter, of the telescope.
  • Pixel size of the camera mounted at the focal plane of the telescope
  • The central wavelength, lambda, of the filter used for the analysis, if any. We recommend using a red filter. If no filter are used one should set lambda at 550nm.
  • Average local seeing conditions in arc seconds where the setup is installed. SKW uses it in in collimation score calculation. The model accuracy is better when providing a current estimation of the local seeing for the analysis. This value does not need to be very precise, a +/-0.5" (arc-second) tolerance or so is good enough.

This minimal configuration allow to use SKW for simulation only. To test and align the telescope optics and components a model is required.

The instrument settings form is divided in 3 zones:

1. A vertical tool bar containing the command buttons that allows to edit the instruments

2. A list of all available instruments

3. A form that allows to configure the selected instrument

For consistency purpose, instruments cannot be edited when at least one instrument is connected. To be able to edit the instrument settings you must disconnect all instruments.

Configure your telescope

Focal length in millimeters of the scope must be defined.

Focal reducer as a factor, a value less than one reduces the focal length by the given factor. Valid reduction faction range is between 0.6 and 1.0. Enter one (1), the default value, when the OTA is used at its native focal, without any reducer.

As a model is built for the optical specifications of the scope any changes on its focal length requires a new model. However you can use this parameter to adapt the model to a focal reducer or extender focal without a new model.

Aperture in millimeters (mm) of the scope must be defined.

Central obstruction in percent (%) of the aperture diameter.

It is not uncommon that the central obstruction given by the manufacturer is off. Therefore we recommend to measure the central obstruction by your own mean. To calculate the central obstruction, you should measure the diameters of the primary mirror and secondary mirror, including its mount and cover, since those can be quite larger than the secondary mirror itself.

You then divide the diameter of the secondary, including its mount/cover, by the diameter of the primary and multiply it by hundred : M2/M1*100 = Central obstruction in percent

To configure a refractor without central obstruction you must define a central obstruction equal to zero.

Pixel size in microns of the camera mounted at the focus of the scope. This value can be changed at any time, it is not model dependent.

Lambda, in nanometers (nm), is the central wavelength of the filter used for the analysis, if any. We recommend using a red filter. If no filter are used one should set lambda at 550nm. 

We recommend to select the red filter and to enter the middle of the red filter bandwidth (mostly likely 650 nm).

Local seeing conditions in arc seconds (") corresponds to the average seeing conditions of the site where your instrument is located at the time of the analysis.

The model accuracy is better when providing a current estimation of the local seeing for the analysis. This value does not need to be very precise, a +/-0.5" (arc-second) tolerance or so is good enough.

Using a model to measure the optical performance of your telescope

SKW use AI (Artificial Intelligence) to retrieve and then to analyze the wavefront of your telescope. To achieve this SKW has been trained to learn the relation between a wide database of aberrated defocused stars and the corresponding aberrations expressed in a quantitative way (by numbers). An artificial neural network (NN) is trained with the learning data resulting to mathematical model which is stored in an encrypted file called the mathematical NN model. To analyze the optical performances of your scope you need a model adapted to your telescope optics.

NN model is a file containing a neural network model used by SKW to analyze the optical performance and alignment (aka collimation) of your telescope mirrors or lenses. 

The extension of the model file compatible with SKW is .wfm

Type defines which type of model you are requesting, either trial or permanent. A trial request will lead to a trial PPU model. Usually only one trial PPU model is provide for a given SKW license and user.

Request is an option that allow to select how to save the request. It can be either saved in a file or send by email

Double pass is a check box that allow to request a model that will be used in a laboratory on an optical test bench in double pass with artificial star(s). 
When using SKW under the sky with an actual star this box should be unchecked. It is used for advanced models and versions of SKW.

Do not use double pass for a model that will be used on a telescope using defocused stars in the sky as light source.

Selected direction allows to select on which direction the telescope will be defocused to capture the defocused star. In general the extrafocal direction is chosen but if for some mechanical reason (e.g. not enough space to move the focuser extrafocal), the intrafocal direction can be used instead.

Each model is generated for a given direction, prior requesting a model, we recommend to carefully check if there is enough space on the focuser travel toward the selected direction. In case that there is a big difference between intrafocal and extrafocal, we recommend to select the direction where there is more space on the focuser travel. 

Hardware acceleration allows to reduce the processing time by doing parallel processing. 


No hardware acceleration. The entire image is processed in a sequential way


When the hardware acceleration is done by the CPU, the input frame is subdivided in equal parts according the number of CPU available on the computer. That means, all parts are processed at the same time. As each parts are smaller than the entire frame by a factor equal to the number of CPU available on the computer, the total time required to process all parts is smaller than the time required to process the entire frame in a sequential process.


The hardware acceleration is delegated to GPU. This option is not currently available for SKW

Requesting a model for your telescope

Push the button to generate a request that contain the optical specification of your telescope. 

You can either save the request to a file and send it later by email to or send an email directly to license should your machine has a email client.

To send the request by email directly your computer must have a mail software installed. If your computer does not have a mail software (email client application) you must save the request to a file and then copy it to a computer having a mail software to send it to 

Our NN models are protected and encrypted and therefore they can only be used on the machine where the model has been requested and with its related SKW license. A model is built and limited to the optical specifications provided at the time of the request. You must request a different model for each telescope, as well as for each machine and related SKW license.

Prior requesting a permanent model you would purchase it from Innovations Foresight. Once purchased you can enter the order number in the IF! order # field.

Loading the requested model

Since SKW has been designed to work off-line,without any Internet connection, the model corresponding to the request will be sent back to you by Innovations Foresight via email.

Once received you must save the model file (file with .wfm extension) to the working folder of SKW then press the button and chose the corresponding model file and press the open button. Remember that you have 10 days from the time the model was been created to register it with SKW.

If the model is compatible with the telescope optics and match with the SKW license installed on the computer where SKW is running, the following confirmation message will be displayed :

In case of error caused by incompatible optics or by a machine that is not the one where the request has been sent, the following error message will be displayed :

In case of error, you must contact our support team!

Removing the model

To replace a model by another your must first clear the loaded model.

To proceed, press button.

Without model SKW will not allow to analyze image captured with your telescope. However you can only use the SKW simulator.

To replace a trial model by a permanent model, you must first clear the trial model and then load the permanent model instead.