How to Use and Set Up SyQon Prism for PixInsight

To make things easier, here you can find all the information on how to use it and how to set it up.

Video guide

Watch the full setup and usage walkthrough directly here.

Overview

The SyQon Prism PixInsight script allows PixInsight to run the Prism CLI denoise engine directly on your images.

What the script does

It exports the current image to a temporary FITS file, runs Prism CLI in headless mode, and then imports the denoised result back into PixInsight.

What you need

You need the Prism executable, the related internal folder, and the PixInsight script repository enabled inside PixInsight.

Important: the Prism executable and the internal folder must stay together in the same location. They do not need to be installed. Just move both of them to any convenient folder on your computer and keep them together.

1. Prepare Prism CLI

1

Get the Prism files Download Prism CLI from https://www.syqon.it/prism.
2

Keep the files together Make sure the Prism executable and the internal folder remain in the same directory.
3

Move them to a convenient location Do not install them. Simply place them somewhere easy to access, such as a tools or applications folder of your choice.

Suggested examples

Windows: a custom folder such as C:\AstroTools\PrismCLI

macOS / Linux: any convenient folder you prefer where both the executable and internal stay together

2. Install the PixInsight Repository and Script

1

Open the repository manager In PixInsight, go to Resources → Updates → Manage Repositories.
2

Add the repository Add this repository URL:
https://raw.githubusercontent.com/SyQon-Hub/PixInsight_Scripts/refs/heads/main/
3

Check for updates Go to Resources → Updates → Check for Updates.
4

Install the SyQon Prism script Install the script and restart PixInsight if prompted.

After installation: the script will appear in SyQon → Prism.

3. First-Time Setup

1

Open the script Launch SyQon → Prism inside PixInsight.
2

Open settings Click the wrench icon.
3

Select the executable Choose the Prism CLI executable from the folder where you placed it.

Windows executable

prism_cli.exe

macOS / Linux executable

prism_cli

4. Running Prism

1

Open your image Load the image you want to denoise in PixInsight.
2

Launch the script Open SyQon → Prism.
3

Select the image Choose the target image in the script interface.
4

Configure the parameters Set the model and processing values you want to use.
5

Process the image Click OK. The script will export the image, run Prism CLI, and import the denoised result back into PixInsight.

Progress feedback

You can monitor progress in the PixInsight console. Example:

Progress: 36% (9/25 tiles)

5. Recommended Settings

Setting	Recommended Value
Model	prism_deep
Tile Size	512
Overlap	128
Pad	512
Strength	0.85
Use Temp Stretch	Enabled
MTF Target	0.15
Use AMP	Enabled

6. Temporary Files

Windows

C:\Users\<username>\AppData\Local\Temp\SyQonPrismCLI

macOS / Linux

/tmp/SyQonPrismCLI

7. Troubleshooting

Issue	Suggested Fix
Prism executable not found	Re-select the executable in the script settings and make sure it is still next to the internal folder.
GPU problems	Enable Force CPU.
DirectML issues on Windows	Enable Disable DirectML.

Check this first: if Prism does not start correctly, verify that the executable and the internal folder were moved together and are still in the same directory.

8. Recommended Linear Workflow

For linear data, the recommended workflow is:

A

Enable Temp Stretch Keep temporary stretch enabled for better evaluation and denoise handling on linear data.
B

Set MTF Target Use 0.15 as the recommended value.