Why Buy New Eyepieces?

[DRT]

 the eyepiece is half the optical system

Is that true for all types of scope?

An eyepiece straight in the draw tube of a refractor, yes, no doubt about it. But what about the diagonal or the secondary of a reflector?

Would it not be more accurate to say the eyepiece is normally one third of the system?

[Stub Mandrel]

If you count optical surfaces, then lenses have a 2:1 advantage. Count individual lens elements and you might as well do awqay with the mirrors altogether, they obviously aren't important ;-)

[Charic]

I believe even if I had the best eyepieces in the World which are ???????? and a ???????? telescope, my own, uncorrected eyes would still  be my downfall?

I had perfect vision  until about 1989, started with my dominant right eye, getting short sighted, and subsequently my left, but with less correction,  and as my age progresses, it can only get worse, unless I have corrective surgery?

My Son has just had £4.5k of laser surgery to correct his vision, he's over the Moon with the result.

My pupils are smaller than they should be for my age according to the opticians?   I need corrected vision primarily for driving, but not suitable for laser surgery was the advice given!

I can see without correction, voles crossing the road, HGV's coming the other way, and most signage ,  the shapes and colours of the signs give you a better clue, you don't have to read them!  But with correction, I don't think I have a problem. It all looks good, yet I don't wear specs at the telescope. Maybe I should get some single vision glasses, or invest in some Dioptrx from TeleVue should my Delos EP  work out to be a keeper.

I believe  your own eye / brain combination can often make good, that, which is provided from  a poorly or inadequate system set-up, but only to some degree.  I also believe that If I collimate my telescope to what I believe is 100% efficient, some of you would still find an issue, due to your own eyesight and perception, were all different after-all.

The whole system from entry-telescope to exit-pupil needs to be  in tune to the only important thing that matters, the end user, and in some cases  only realised by trial and error.

[John]

Is that true for all types of scope?

An eyepiece straight in the draw tube of a refractor, yes, no doubt about it. But what about the diagonal or the secondary of a reflector?

Would it not be more accurate to say the eyepiece is normally one third of the system?

I guess others will have a different take on this but I tend to regard the secondary as part of the scope optical system with newtonians and catadioptrics because the scope won't work without it. 

With refractors (and reflecting cat systems) you can use them straight through and I believe Japanese observers prefer that.

Either way, every photon that comprises the image will go though the optical elements of the eyepiece so you want those to be working at least as well as the other components.

We can't do much about the weather or seeing conditions apart from travelling or moving house. We can't do much about the state of our eyes either.

We can do something about some of the other components of the chain, ie: the scope and eyepieces.

[DRT]

What is your opinion on diagonals, John? I have chosen to buy top end diagonals but mainly because of things I have read rather than what I have observed. I have a general rule of not putting anything in the light path that is certain to be a weak link but have not done enough comparison of individual components to understand exactly how much difference good and bad in each of them make to the overall viewing experience.

[Mak the Night]

I used to call it being an "ocularholic" 

I'm still rather weak in this regard - despite being determined to "downsize" I've still managed to end up with 14 of the things ....

Yeah, I am definitely an ocularholic lol. Right now, I'm really jonesing for a 10mm Delos. 

[Charic]

......do Hens teeth  and S/H Delos have something in common, their not readily available?

[Chris]

Cheap eyepieces can be all that's needed in slow scopes such as your f/8 150pl, and my slow refractors.

Owners of faster f/4 scopes may be driven half mad by comet shaped stars if using cheap eyepieces. Big fast Dobs and expensive glass go hand in hand for example. 

[John]

I think edge correction is much less of an issue in slower scopes due to the light cone being less steep and consequentially less challenging for the eyepiece to handle but other eyepiece generated issues such as light scatter, ghosting and reduced light transmission will still be present even with slow scopes.

I ought to add that I'm not trying to advocate uber-expensive eyepieces, just decently designed and made ones. These can usually be bought for the £30-£50 per unit unless very wide fields of view are desired.

[Stub Mandrel]

> just decently designed and made ones. These can usually be bought for the £30-£50 per unit

That's reassuring.

[Stub Mandrel]

Do you like to show the sky to others?   Are you working with kids?   Perhaps sharing your experience with friends?

Consider a zoom eyepiece.

http://stargazerslounge.com/topic/258168-observing-with-friends-kids-visitors-the-wow-factor-of-the-zoom/

They're my photons I tell you! Mine!

Well there is some interest from the family - my Daughter is 16 and she stayed up for the Lunar Eclipse.

To my shame  I spent  about six hours on imaging last night, and the only scope I looked through was a finder.

I was planning to 'go visual' when the batteries went flat, but by the time they did there was 1/8" of ice on anything left at grass level! Not a bit of dew at scope level, so know I know what a 'grass frost' really is!

I suppose the truth is I find looking through an EP for more than a few minutes uncomfortable, so imaging is my priority, but I need to find excuses to look more!

Now I have an intervalometer, I realise I should have taken my spare tripod, as I had two scopes and could have been looking through one instead of sitting in the car listening to the shipping forecast and world service.

[digital_davem]

They're my photons I tell you! Mine!

Well there is some interest from the family - my Daughter is 16 and she stayed up for the Lunar Eclipse.

To my shame  I spent  about six hours on imaging last night, and the only scope I looked through was a finder.

I was planning to 'go visual' when the batteries went flat, but by the time they did there was 1/8" of ice on anything left at grass level! Not a bit of dew at scope level, so know I know what a 'grass frost' really is!

I suppose the truth is I find looking through an EP for more than a few minutes uncomfortable, so imaging is my priority, but I need to find excuses to look more!

Now I have an intervalometer, I realise I should have taken my spare tripod, as I had two scopes and could have been looking through one instead of sitting in the car listening to the shipping forecast and world service.

You imaging guys are dedicated.  I've done quite a bit of fine art long exposure landscape photography at (where long exposure means 5 minutes) and half a dozen 5 minute shots is all I can take... 6 hours, you must be nuts    

[LukeSkywatcher]

I have quite a few EP's and the only 5 i would hang onto if it came to selling, are my Hyperion 8-24 zoom and my 8,15,25 and 30mm Vixens. 

I know the 8-24 zoom just about covers my Vixens but the Vixens for me have the edge. I just love them. The zoom was bought purely for ease of use and no swapping out needed..

[Mak the Night]

I tend to hang on to stuff as it might be useful some day. I still take out Plossls I hardly ever use anymore as they're in my case. These include 8 and 11mm TeleVues that rarely ever see a diagonal these days, 12 and 15mm Celestron Omni Plossls which look really shiny and I still quite like but also don't get used much now and an Omni 2x shorty Barlow that's a tad redundant now. Last night I only took one smallish (slightly modified) Celestron Eyeopener case out to observe M42 predominantly. This is because it's become the new home for my 10mm Delos and I wanted first light with it. It also houses a 32mm Celestron Plossl which has more or less been replaced with the TV 32mm in my Orion case. It still comes in useful though if I only take one case out and I want a big Plossl. I'm probably a bit of a closet eyepiece hoarder lol.

[LukeSkywatcher]

 I'm probably a bit of a closet eyepiece hoarder lol.

I think most of us are.

[Knighty2112]

I'm going to be buying a dual 2"/1.25" diagonal in Feb/March time so I can start my 2" range too! Hehe!

[Merlin66]

My 2c....

When I was younger and had better eyesight as well as "dedication" to observe all night I "invested" by upgrading from the UO Orthos I was using to the "new" TV Plossls.

I found they allowed me to see 15.5 mag stars (during the SN Search program) with the 12" f5 just 15 Km from the centre of Melbourne.

I think the last eyepiece I bought was around 1990.....

It's now reached the stage where I think the eyepieces will outlast my eyes. I don't see the need to further "upgrade" the ones I have - I'm sure they probably would be nice, but probably not enhance my viewing.

Moral: Good eyepieces can and do last a lifetime.