Quote:
Originally Posted by TareqPhoto
I understand, and that is a good point, but does ED APO let's say doublets for example be good enough for imaging then or it must be a triplet? So is an ED APO scope small one for example about $300-600 nice for imaging or this is not bad but it won't do better as well?
What is the problem of L filter if using with an achro refractor?
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The L Filter (Luminance filter) transmits light across a 300 nm band (~400 to 700nm) so will show up deficiencies in optics and in different focus points for differing wavelengths (colours) far more readily than a typical narrowband filter with a 3, 5 or 6 nm 50% bandwidth.
Best
JA