Stack on Astro Live Stacker

Quick Start

Thu, 11 Jun 2026 00:33:38 +0000

Introduction

By the end of this chapter, you will have:

Configured the only required settings for a quick start with ALS’s default settings.
Started your first stacking session and obtained your first results.

In the shoes of the character…

Throughout this journey, you will embody a new ALS user:

Username: Your username is astrogeek
System used: You use ALS on a Linux system
Organization of subs: Your acquisition system saves the subs in the astroshots folder of your home directory, organized by target with subs in Light subfolders.

Concepts

Thu, 11 Jun 2026 00:33:39 +0000

Introduction

By the end of this chapter, the basic concepts of ALS will be familiar to you.

You will understand what ALS does and how it does it.

Stacking

Stacking is the process of combining multiple subs of the same target to generate a more detailed and contrasted image than a single sub.

The quality of the result increases as more subs are used.

Comparison of 8 stacking results
The number of stacked subs is indicated at the top left of each image

A successful session

Thu, 11 Jun 2026 00:33:39 +0000

📘 Introduction

This chapter is your roadmap for running a successful ALS session and monitoring its progress.

It wraps up the presentation of ALS main concepts before you dive into the user interface guide.

⚙️ Setup

Whether you’re shooting DSO live, preparing data for detailed post-processing, or diving into something more artistic, these steps will help you get the best out of ALS every time.

✔️ Choose Your Profile

EAA: For live imaging

main controls

Thu, 11 Jun 2026 00:33:39 +0000

Introduction

During this chapter, you will:

get familiar with ALS main controls
Deepen your knowledge on key features

Overview

The ALS control station is the Main Controls interface panel

Located on the left side of the ALS interface, it organizes the most used controls and displays into sections:

Session

Session controls and status
Stack

Stack controls and stack information
Image Server

Image server controls and status
Image Saver

Image saving tools

Stacker

Thu, 11 Jun 2026 00:33:39 +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

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class CheckShape,CheckAlign,FirstSub test

Alignment

If alignment is ON

Quick Start

Thu, 11 Jun 2026 00:33:38 +0000

Introduction

By the end of this chapter, you will have:

Configured the only required settings for a quick start with ALS’s default settings.
Started your first stacking session and obtained your first results.

In the shoes of the character…

Throughout this journey, you will embody a new ALS user:

Username: Your username is astrogeek
System used: You use ALS on a Linux system
Organization of subs: Your acquisition system saves the subs in the astroshots folder of your home directory, organized by target with subs in Light subfolders.

Concepts

Thu, 11 Jun 2026 00:33:38 +0000

Introduction

By the end of this chapter, the basic concepts of ALS will be familiar to you.

You will understand what ALS does and how it does it.

Stacking

Stacking is the process of combining multiple subs of the same target to generate a more detailed and contrasted image than a single sub.

The quality of the result increases as more subs are used.

Comparison of 8 stacking results
The number of stacked subs is indicated at the top left of each image

A successful session

Thu, 11 Jun 2026 00:33:38 +0000

📘 Introduction

This chapter is your roadmap for running a successful ALS session and monitoring its progress.

It wraps up the presentation of ALS main concepts before you dive into the user interface guide.

⚙️ Setup

Whether you’re shooting DSO live, preparing data for detailed post-processing, or diving into something more artistic, these steps will help you get the best out of ALS every time.

✔️ Choose Your Profile

EAA: For live imaging

main controls

Thu, 11 Jun 2026 00:33:38 +0000

Introduction

During this chapter, you will:

get familiar with ALS main controls
Deepen your knowledge on key features

Overview

The ALS control station is the Main Controls interface panel

Located on the left side of the ALS interface, it organizes the most used controls and displays into sections:

Session

Session controls and status
Stack

Stack controls and stack information
Image Server

Image server controls and status
Image Saver

Image saving tools

Stacker

Thu, 11 Jun 2026 00:33:38 +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

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class CheckShape,CheckAlign,FirstSub test

Alignment

If alignment is ON

Quick Start

Wed, 24 Jun 2026 14:43:39 +0000

Introduction

By the end of this chapter, you will have:

Configured the only required settings for a quick start
Started your first stacking session and obtained your first results.

Initial configuration

On the first start, ALS introduces the configuration steps required to get started:

ALS needs to know the paths of two critical folders:

The Scan folder: The folder where ALS monitors the arrival of new subs.
The Work folder: The folder where ALS saves the produced images.

ALS welcome screen with setup options

Concepts

Thu, 11 Jun 2026 00:33:39 +0000

Introduction

By the end of this chapter, the basic concepts of ALS will be familiar to you.

You will understand what ALS does and how it does it.

Stacking

Stacking is the process of combining multiple subs of the same target to generate a more detailed and contrasted image than a single sub.

The quality of the result increases as more subs are used.

Comparison of 8 stacking results
The number of stacked subs is indicated at the top left of each image

A successful session

Thu, 11 Jun 2026 00:33:39 +0000

📘 Introduction

This chapter is your roadmap for running a successful ALS session and monitoring its progress.

It wraps up the presentation of ALS main concepts before you dive into the user interface guide.

⚡ Startup

ALS can be launched either from its graphical interface or directly from the command line, depending on your workflow or automation needs.

Graphical launch:
Simply start ALS as any other application. You’ll land in the main window, ready to configure your session.

main controls

Thu, 11 Jun 2026 00:33:39 +0000

Introduction

During this chapter, you will:

get familiar with ALS main controls
Deepen your knowledge on key features

Overview

The ALS control station is the Main Controls interface panel

Located on the left side of the ALS interface, it organizes the most used controls and displays into sections:

Session

Session controls and status
Stack

Stack controls and stack information
Image Server

Image server controls and status
Image Saver

Image saving tools

Stacker

Thu, 11 Jun 2026 17:57:08 +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
Minimum matches	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

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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