Quote:
Originally Posted by mattyb217
A few questions... That might sound a bit silly...
1- is there any such thing as a good eyepiece, Or are the all the same?
2- what size eyepieces work well?
3- what & how do filters work/ what are they used for?
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1. Yes. And many rather ordinary ones, and some notoriously awful ones.
2. That depends on your telescope. What work well in small refractors generally isn't a good match for a fast newtonian, and vice versa.
The reason is the curvature of the field of the telescope, and the amount of coma differ significantly according to the type of telescope -and can be quite different. An eyepiece that suits one type probably isn't a good match for another type.
Unfortunately eyepiece manufacturers do not disclose which telescopes their eyepieces are designed for, so you have to 'suck it and see' which ones you like in your telescope. It's an expensive business unless you can find some mates with good sets you can try before buying.
Consequently when reading reviews of eyepieces you need to take heed of what sort of telescope was used, if its not comparable to yours the review is meaningless.
Secondly, there is no such thing as a 'perfect eyepiece' for all telescopes. Buy what suits yours.
3. Mainly to enhance contrast, and this depends on the spectrum of light from the object you are looking at.
For example Jupiter, where selective colour filters will enhance the contrast of the bands. Or planetary nebulae which emit strongly on the OIII line; using an OIII filter makes everything else much darker - including the sky - and the nebula will literally jump out at you.
