Modules and Processes on Astro Live Stacker

Scanner

Sun, 31 May 2026 06:32:34 +0000

Overview

The Scanner module is the entry point for your subs in ALS.

It is responsible for:

Monitoring the appearance of subs in the scan folder
Loading the detected subs

ℹ️ Existing files are ignored

Files present in the scan folder before the Scanner module is started are not detected

ℹ️ Detection of subs is recursive

Subs are detected regardless of the level of subfolders where they appear within the scan folder

Stacker

Sun, 31 May 2026 06:32:34 +0000

Overview

The Stacker module handles the alignment and stacking of calibrated subs.

Configuration

	Source	Data type	Required	Default value
Alignment ON/OFF	Interface: Stacking controls	ON/OFF	∅	ON
Stacking mode	Interface: Stacking controls	choices: - mean - sum	YES	mean
Detection threshold	Interface: Stacking controls	integer	YES	25

Control

The Stack module is launched in the background at ALS startup

Source	Type	Response
sub(s) in queue	Event	trigger processing

Input

Data	Type
sub at queue front	Image
session alignment reference	Image

Behavior

flowchart LR
Start([START])
FirstSub{{First sub of the session?}}
SetAlignReference[Set sub as alignment reference]
CheckShape{{Sub same dimensions as previous result?}}
CheckAlign{{Alignment ON?}}
AlignImage[Align sub]
StackImage[Add sub to Stack]
ComputeStacking[Compute stacking]
PublishReference[Return alignment reference]
PublishResult[Return generated image]
End([END])

Start --> FirstSub
FirstSub -- YES --> SetAlignReference
SetAlignReference --> PublishReference
FirstSub -- NO --> CheckShape
CheckShape -- YES --> CheckAlign
CheckAlign -- YES --> AlignImage
AlignImage --> StackImage
CheckAlign -- NO --> StackImage
StackImage --> ComputeStacking
ComputeStacking --> PublishResult
CheckShape -- NO --> End
PublishReference --> End
PublishResult --> End

classDef bounds fill: #333, stroke: #666, stroke-width: 2px, color: #BBB, font-family: 'Poppins', sans-serif
classDef step fill: #444, stroke: #622, stroke-width:2px, color: #c6c6c6, font-family: 'Poppins',sans-serif
classDef test fill: #444, stroke: #226, stroke-width: 2px, color: #c6c6c6, font-family: 'Poppins', sans-serif

class Start,End bounds
class SetAlignReference,AlignImage,StackImage,PublishResult,ComputeStacking,PublishReference step
class CheckShape,CheckAlign,FirstSub test

Alignment

If alignment is ON

Save

Sun, 31 May 2026 06:32:34 +0000

Overview

The Save module handles the saving on disk of all images generated by ALS.

Its configuration is managed via ALS preferences

Configuration

	Source	Data type	Required	Default value
work folder	Prefs: Output Tab	path to a folder	Yes	∅
web folder	Prefs: Output Tab	path to a folder	Yes	= work folder
file format	Prefs: Output Tab	choices: - TIFF - PNG - JPEG	Yes	JPEG

Control

The Save module is launched in the background at ALS startup

Server

Sun, 31 May 2026 06:32:34 +0000

Overview

The Server utility module exposes ALS processing results through a lightweight HTTP and WebSocket service.

It is responsible for:

Publishing the latest stacked image and session metrics in the configured web folder
Serving the viewer web application (index.html, JavaScript and icons)
Streaming live new-image notifications to connected browsers over WebSockets

The module runs in its own asyncio event loop and accepts concurrent browser clients. It never alters the processing pipeline; it only serves the web image written by the Save module.