Imaging Techniques

Webcam imaging with Philips ToUcam 740 Pro
Chapter 1 - Overview

  Chapter 2

Image by Philips

General approach

Most of todays best planetary amateur images have been captured with an affordable unmodified webcam. Astro webcamming raised amateur imaging to an amzing level of quality. The common fields of application for nonmodified webcams are planetary, lunar and solar imaging and double stars. Webcam hardware can be modified to long exposure times giving respectable results for DSOs like nebulae and galaxies which won't reach results from commercially available astro CCD cameras. This article concentrates on planetary imaging with non-modified cams.

Usually the webcam is inserted into the prime focus of the telescope instead of an eyepiece. Adapters that can be screwed into the 12M X 0.5 thread of a ToUcam are available, selfmade adapters made from a 35mm film canister are an alternative. Often the webcam is used in conjunction with a barlow lens for extended magnification. One key to the posibilities of webcams is the very small CCD pixel size allowing resolution of fine details. There's no need for high resolution CCDs, even at focal lengths of 6000mm or above planets fit easily into the field of 640x480 pixels. Just pixelsize is the key!

ToUcam with 1 1/4" adapter

Typically webcam imaging is performed in three stages:

  1. Recording multiple single frames (upto several 1000) in an AVI movie
  2. Selecting best movie frames and stack/average them into a single image
  3. Sharpen and postprocess the stacked image

ToUcam @ VMC, 3xBarlow and extension tube in place

Typical imaging session

  Chapter 2