Are large telescopes more affected by “seeing”?
Seeing is defined as the distortions (or lack of) in the atmosphere. The old wife’s tale was that the atmosphere was made up of 8″ cells and that allowed small scopes to “beat the seeing”, by looking right through them. This, of course, has never been proven by any actual research. More likely the rumor got started because small scopes cool down so much faster than large ones. Thus it would appear that the small scopes see right through the “bad seeing”, while large ones are confounded by it, when in reality what is being seen is a thermal issue with mirror mass. What can be said is; that with a mirror of any size, cooled within 1.5 degrees or so of the ambient temperature, the atmosphere will limit the MAGNIFICATION. If a 6″ scope can produce a stable image at 250x so will a properly cooled 30″ scope on the same night. But, on a night with great seeing, your 30″ telescope will easily exceed 1000x and leave the smaller scope in the dust.
