?????

[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?

[AG Hybrid]

Eyepices are like cars in a way. They will get you from A to B. But, depending on your budget, some cars will get you there in more style and comfort. So they are not the same. Not even close.

Your questions are broad and deep subject matters. Have you tried browsing through the beginner's section yet? The answers to your questions are already there.

[mattyb217]

Ok cool no worries I'll check it out thanks

[Steve-hobart]

From someone who is basically starting out as well.
Eyepieces vary. Ive been trying a few and probably my favourite general one so far is a big 2" 30mm gso superview which was not very expensive. What i like is that it is big, large field of view and crystal clear and its very forgiving on where you put your eyeball relative to the eyepiece (some eps arent and you need your eyeball in just the right spot to view things)
Re filters, i tried looking at the moon with my 10" dobsonian and you could see the light coming out of the eyepiece like a torch. Lot of light gathered by the mirror and need to tone it down a bit.

[mattyb217]

Great thanks Steve much appreciated :)

[shenanigans000]

Apart from decreasing overly bright objects like the moon, filters can also be used to emphasize different details in (usually) planets. They also have uses in astrophotography.

Hope all this helps.

Cheers.

[Wavytone]

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.

[mattyb217]

Great thanks everyone for the comments, they all really helped.
Cheers

[Don Pensack]

Perhaps you should do a little reading up.
I recommend "The backyard Astronomer's Guide" by Dickinson and Dyer.
It's the "Observer's Owner's Manual" and it would be wonderful if this book accompanied the purchase of all scopes for newbies.

Each of your questions could elicit a 50,000 word response, with chapters.

Nonetheless, I will try to lead you to a few sites where you can get some decent answers to your questions:
1) A short book that might be considered the owner's manual for the novice:
http://scopecity.com/optics-course-0000.cfm?pn=Beginners+guide+to+tele scopes+and+optics
2) Eyepiece basics:
http://www.quadibloc.com/science/opt04.htm
3) How to evaluate eyepieces:
http://www.eyepiecesetc.com/Eyepiece_Parameters_and_Aberrations _p/ep-parameters.htm
4) Recommendations for how to choose them for a scope:
http://www.eyepiecesetc.com/1X_2X_3X_Magnification_Protocol_p/ep-selection-1x-2x-3x.htm
5) What filters are, what they do, and how to choose them:
Nebula filters:
http://www.eyepiecesetc.com/Choosing_a_Nebula_Filter_p/nebula-filters-explained.htm
and
http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/
Color filters:
http://www.lumicon.com/pdf/3filterspec_prnt.pdf (go down the page until you get to color filters and what they do.
6) Contrast: what it is and how it's improved:
http://www.eyepiecesetc.com/Contrast_in_Eyepieces_p/contrast-in-eyepieces.htm

And if any of the concepts and ideas explained are a little too obtuse, you can always ask more questions. I bet your next set will be a little less generic and a lot more specific. It's a journey, and you're just starting on the trip.