It is not unknown for beginners in this hobby to stare in disbelief at the lunar and planetary pictures secured by the world's best webcam amateur astronomers and lose the will to live. "He must have extraordinary seeing conditions" or "My telescope must be a lemon" are phrases often heard in this context. The factors preventing a planetary observer from achieving the best results are many and varied but, in essence, they boil down to dedication and the following factors (in rough order of importance):
• The observer must do a huge amount of observing to "catch" moments of good seeing.
• The telescope must have precisely collimated quality optics.
• The telescope and observatory should cool quickly to the air temperature.
• The webcam must be focused very precisely.
• Daily information on the stability of the atmosphere/jet stream is vital.
• Image processing knowledge and experience are invaluable.
• No stage of the process should be rushed, especially the image processing.
You will see that I have not specified any particular type of telescope for planetary imaging despite the endless debate on which telescope is best for planetary use. To be honest, the type of telescope is largely irrelevant when compared to the quality of the optics and how accurately they are collimated. An uncollimated telescope is, automatically, a lemon, however good the optics. We will read more about colli-mation later. The world's greatest planetary observers use a variety of telescope types and get good images with every design. In the main, they use telescopes between 20 and 40 cm aperture, with the very best webcam imagers tending to have instruments in the 23 to 28 cm aperture range (corresponding to theoretical resolutions of around 0.5 or 0.4 arc-seconds). However, some telescopes are definitely better than others from a collimation and user-friendliness aspect. I would place user-friendliness way up there on the list of priorities. Becoming the master of your particular instrument is the key to getting good results. Telescopes are rarely 100% hassle-free unless they are handmade to your requirements. I will have more to say on telescope choices, disasters, and lemons in a short while, but first, I would like to address the factors that I have listed above.
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