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Top-end eyepiece advice


DRT

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Hi Derek

Not sure I'd bother with TV or Pentax if I had an f/10 scope. Can't see the point myself. Save some dough buddy buy something else instead.

Maybe put the money towards that camera you want to image with ;)

:eek: (I'm not saying anything!  :grin: )

Cheers

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Alan Green,

I bought a Moonlite focuser for my Meade and I have removed it now as I find I never use it, if you pratice enough with the scope,  I know that is down to wondeful British weather, I find now I can focus perfectly well with the scope focus system. Having said that though I did think it was awful for a long time and that's what pushed me to spending 345 quid. I now just use it as it was designed.

I will point out that I get about half of every month at the very worst under clear skies, even January has been 14/27 so on course but December was below par with only 10 nights.

Alan

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I would go with either the Pentax XW or Delos.  Visually it tends to be tie for most users.  Both have comfortable eye relief.  So I would choose based on available focal lengths you might need.  50x, 150x, 200x, 250x or there abouts would be my choices.  I typically like a 3x gap from my lowest power to next highest.

Now another option to seriously consider, since will cost about the same given you are considering pricey eyepieces, would be the Leica ASPH Vario Zoom 17.8-8.9mm.  It is quite an amazing performer and very comfortable.  It is a bit picky though with scope designs.  Great in APOs.  Newts give it a bit of an off-axis problem.  Not sure how it reacts in SCTs.

Take a read here - http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4534474/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1

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Now another option to seriously consider, since will cost about the same given you are considering pricey eyepieces, would be the Leica ASPH Vario Zoom 17.8-8.9mm.  It is quite an amazing performer and very comfortable.  It is a bit picky though with scope designs.  Great in APOs.  Newts give it a bit of an off-axis problem.  Not sure how it reacts in SCTs.

Take a read here - http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4534474/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1

I've managed a short session on my SCT C8 here:

http://stargazerslounge.com/topic/206108-leica-zoom-25x-50x-asph-178-89mm-baader-vip-barl:w/

Not at all as extensive as Andreas has done, nor as experienced eye as you have.

http://www.cloudynights.com/item.php?item_id=2795

But I do see it performs very well against the BCO 18 and 10 optically, in addtion to comfortable eye relief easy of use.

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Hi Derek

Not sure I'd bother with TV or Pentax if I had an f/10 scope. Can't see the point myself. Save some dough buddy buy something else instead.

Maybe put the money towards that camera you want to image with ;)

Please explain why an f10 scope and high-end eyepieces don't mix. My bank manager loves the idea, I just need to understant the theory :wink:

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The faster the scope the less forgiving on eyepiece performance, hence there is no need to have top of the range expensive eyepieces that are tested to F3 when you have an F10 scope. Thus a very important point made above.

One thing to consider, over the long haul is it really cheaper to buy eyepieces to suit one scope when you can buy eyepieces that will suit all your scopes and any future scope you may want ?  (there are quite a few eyepieces that fall into the latter)

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Please explain why an f10 scope and high-end eyepieces don't mix. My bank manager loves the idea, I just need to understant the theory :wink:

As Pig / Shaun says, faster scopes benefit a bit more from top end eyepieces but slower scopes get some benefits too so don't exclude yourself from those. Top end eyepieces work well in all scopes   :smiley:

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The faster the scope the less forgiving on eyepiece performance, hence there is no need to have top of the range expensive eyepieces that are tested to F3 when you have an F10 scope. Thus a very important point made above.

One thing to consider, over the long haul is it really cheaper to buy eyepieces to suit one scope when you can buy eyepieces that will suit all your scopes and any future scope you may want ?  (there are quite a few eyepieces that fall into the latter)

OK, I now get the high-low f-factor. Do my existing range of X-Cels qualify as EPs that suit many scopes? I have no experience of anything better so only have these as a point of reference.

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While true there some other factors to consider. light scatter, stray light, contrast and star sharpness. Fast or slow, the slow scope will also benefit in a lot of these areas, otherwise a large part goes into paying for extra FOV. 

I have one really cheap eyepieces in a 66 degrees skywatcher. While I can't complain for what it has delivered for the price, having somewhat more experience now using the eyepieces I own , the sky background is substantially less dark in the SW, even compared to my 8mm BST at about twice the price and larger exit pupil. When it comes to sharpness  and splitting doubles it weaknesses become apparent too, it is the first on the list to be upgraded right now for me, perhaps a 6mm ortho :smiley: .

That said, for an extra 20 - 30 pounds over really cheap  you can get a lot more already where these differences can already be much smaller to notice, once you go above that 50 - 60 pounds. I would not argue with the fact a medium range eyepiece such as the Xcells aren't good enough in the scope in question, I don't know not having the experience myself. I've never looked through a slow scope anyway with such an eyepiece, but I can appreciate there is a lot to be said for what Steve said.

In the end of the day how much you are prepared to pay for incremental improvements is different for everyone I suppose. The closest I own to premium is an old pentax XL 10.5 mm.  In a scope such as mine which is quite fast anyway, I found the cost getting this easily justified without regret whatsoever once I used it a few times. Not just in terms of off axis behaviour, but also enhanced colour, star sharpness, nice flat field in a reasonably large FOV, luvly jubbly :D Besides that, it should work well in pretty much all scopes in the future I may end up getting. 

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If you can afford them, then TV and Pentax are the best that money can buy and will get the best out of the 'scope that you have. EPs will not be the limiting factor.

If you can't, then fear not, there is now a whole raft of quality EPs that will produce excellent (but not the outstanding that you would expect from the aforementioned) images that the majority of us are more than happy with.

The choice at the end of the day, is yours.

However, you've had some good advice on focal length, which I thought was the real crux of the matter.

Cheers

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The faster the scope the less forgiving on eyepiece performance, hence there is no need to have top of the range expensive eyepieces that are tested to F3 when you have an F10 scope. Thus a very important point made above.

One thing to consider, over the long haul is it really cheaper to buy eyepieces to suit one scope when you can buy eyepieces that will suit all your scopes and any future scope you may want ?  (there are quite a few eyepieces that fall into the latter)

Sorry, that is not quite right. In my F/10 scope the XWs, Naglers, and Delos outperformed cheaper EPs I had before. More expensive EPs are not just about better control of aberrations (which is more difficult in fast scopes), they are also about better coatings and glass, which yields better control of internal reflections and glare, and improved transmission. These features are much less sensitive to the width of the light cone.

Your point on having EPs to suit all scopes you own or make them future proof is very important.

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Sorry, that is not quite right. In my F/10 scope the XWs, Naglers, and Delos outperformed cheaper EPs I had before. More expensive EPs are not just about better control of aberrations (which is more difficult in fast scopes), they are also about better coatings and glass, which yields better control of internal reflections and glare, and improved transmission. These features are much less sensitive to the width of the light cone.

Your point on having EPs to suit all scopes you own or make them future proof is very important.

Michael I cheated and used the word "performance"  as it has many contributors, such as the others you mentioned :grin:  :grin:

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I am trying to get my hands on some cheaper eyepieces to compare in my Meade LX and SW Mak 180mm to see just how much of a difference there is in slow coaches, there is a chance I can get a 28mm SW to try alongside the 26mm Nagler or maybe the 31mm.

Very good point someone made about ghosting, I have to say i always forget this in my reports, some Meade UWA's used to show this mainly on the likes of Jupiter and Venus but I can't say I see it any of my other eyepieces. I used to do a test where I placed Jupiter outside the FOV and checked for scatter and ghost but lately I have forgotten about it. I know in the past I have seen some fairly bad examples of this in Series 5000 eyepieces but if the scope is driven it never really was a problem, to me at least.

Alan

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