APT User Guide - Dithering & Guiding
Channel: Southern Cross Amateur Astro
Date: 2024-01-26

Astro Photography Tool Video User Guide
Features - Dithering & Guiding

APT can communicate with various guiding programs and devices in order to monitor and control the guiding for your mount. An important aspect of this communication is to provide dithering.
 
Dithering is a gentle, random change of the telescope position between the exposures. By doing this celestial objects are placed in slightly different positions on every image while sensor defects like hot/cold pixels, dust or banding noise remains in a constant or almost constant position. During image stacking the stars are detected and all frames are aligned based on star positions - this means that the objects become constant while defects become random. All major stacking applications for image post-processing provide methods based on "sigma clipping" / "kappa-sigma clipping" pixel rejection. These methods exclude the random data and preserve the constant signal. As a result, in the stacked image, there will be a large reduction in defects and noise (improved signal to noise ratio - SNR). The more images you use in the stack, the more noise and defects will be removed. In order for the sigma clipping to be effective there is need to use at least 6 light frames.

Online written guide - Dithering & Guiding
https://www.astrophotography.app/usersguide/dithering_and_guiding.htm
Online written guide - Multi-camera Dithering / Synchronising
https://www.astrophotography.app/usersguide/multi_camera_dithering___synchronizing.htm

APT Links
Homepage: https://astrophotography.app/
Forums: https://aptforum.com/phpbb/
User Guide: https://www.astrophotography.app/usersguide/

Support APT!
Having alternatives drives progress!
https://astrophotography.app/alternatives.php

SCAA Dithering Calculator APT Forum Link
https://aptforum.com/phpbb/viewtopic.php?p=44095#p44095

Astronomy Tools Guide Scope Suitability Calculator
http://astronomy.tools/calculators/guidescope_suitability

Interactive Dithering Calculator
https://www.astrohowto.com/interactive-dithering-calculator/

00:00 Intro
01:00 Basic Settings
12:27 Multi-Cam, Just a quick look
15:23 Dithering Distance Explained