Imaging Techniques

Webcam imaging with Philips ToUcam 740 Pro
Chapter 5 - Premises for high resolution imaging

Chapter 6

To be able to obtain high resolution images two main factors have to cooperate:

1. Condition of equipment


Proper scope collimation is a must! Imaging without the best collimation possible is simply a waste of opportunities and will result in a loss of possible detail resolution. Collimation should be checked before any imaging session and readjusted if necessary, ideally after the scope reached total thermal equilibrium. Instructions on collimating different types of scopes are available by various sources. If the scope hasn't been tossed around a lot after it's last collimation, a check or small corrections performed on a high magnified airy disk pattern of a focussed star should be sufficient. The better the seeing, the better the precision of the collimation will be.
In addition to the scope collimation all parts inside the optical path during imaging such as diagonal mirrors etc. should be checked for correct adjustment.
The potential of many high quality scopes is wasted by improper collimation. Scopes are designed to be collimated, don't hesitate to do so!

Thermal equilibrium

A scope works best when thermal equilibrium with it's surrounding is reached. Depending on scope type and size and temperature difference between the scope's storage location and observing/imaging place the cooldown can take upto several hours. Cooling fans speed up the cooling process and help a scope to follow changing temperatures.
If a scope hasn't reached thermal equilibrium tube currents will occur and blur and distort the image.

2. Atmospheric conditions


Example of mars in heavy seeing conditions - click image for video-file
(DivX codec required)


Chapter 6