Dry nitrogen is the way. Argon will get out fast - it's lighter than air and floats up. Carbon dioxide is corrosive in combination with water vapor (omnipresent). I do not know your telescope design, but if the tube opens to atmosphere even briefly all exercise would have no use.
Correction: Argon is heavier than air -my bad. Does not change the situation to better, though...
Last edited by mplanet62; 21-05-2012 at 10:43 AM.
|