What are all these eyepieces?

[Rick Parrott]

Hi all!
I'm a bit :screwy: so, is there an article someone could point me to explaining features / benefits between Plossl, Super Plossl, Camera Projection, Super View etc.? I do understand that generally more $$ equals better, but I also figure that some types may suit my set-up better...

[mental4astro]

Hi Rick,

Plossl and Super Plossl are the same thing - just marketing hype. These are a good optical match with Newtonians. Biggest draw back with this 100 year old design is the eye lens gets smaller and eye relief shorter as focal length shortens. Newer designs make use of more exotic glass types that give a larger eye lens and much longer eye relief in shorter focal lengths. Plossls ain't Plossls though! The orthodox Plossl design is more difficult and expensive to produce than the cheap ones, and the optical quality is hence better too. Even so, if pennies matter, the inexpensive plossls are still very good. The slower the Newtonian, the better. They do very well in slow refractors, SCTs and Maks too.

'Super' (with no plossl following the 'super') are actually Kellner eyepieces. It is an old eyepiece design that shows a lot of aberrations in fast scopes. These are only a step up from Ramsden and Huyghenian, but really are not much chop today. Better than nothing, sure, but really, a long way down from Plossls.

'Camera Projection' is a dodgy term. It can mean that the eyepiece has an inbuilt M42 thread so a camera adapter can be used with it. These eyepieces are usually Plossls.

'SuperView' is a GSO line that are Erfle eyepieces, typically found in binos, so are better suited to refractors, SCTs and Maks, but binos they are designed for. They can show a lot of astigmatism and some field curvature in Newtonians - yeah, I know, a bit of jargon here, but it just means they are not the best in Newtonians. But for the price, they are really good value wide field eyepieces for Newtonians.

The following Wiki article will explain a many more eyepiece designs. Only problem though is many companies name their eyepieces to sound better than they are (like 'Super'...):

https://en.wikipedia.org/wiki/Eyepiece

The picture below shows what different eyepiece designs look like. The '*' degree figure with each eyepiece design corresponds to the typical Apparent Field Of View of the design.

Great eyepieces unfortunately do cost more. But there are a few gems out there that are modest in price, and great performers too, but not 'perfect'. You do need to look for them.

[N1]

Alex' post pretty much covers it, but I might add that raw optical performance of an eye piece has less impact on the price than one might think. It can be had at very modest prices.

People pay big dollars to combine high performance with aspects of comfort and aesthetics, the main ones being eye relief and apparent field of view, so much so that the premiums paid for those two far exceed the cost of performance alone. Compare prices between Plossls and 100° wide field eyepieces, or a 12.5mm Abbe ortho to something like the 12.5mm Docter UWA and you'll see what I mean.

The good news is that you can decide for yourself how much "extra" beyond just performance you want or need.

[mental4astro]

I totally agree, Niko. Thanks for adding that, :thumbsup:

One does need to do a lot of reading and trying out of different eyepieces in different scopes, and then come to their own decision of what best works for them, including if $$$ need to be counted.

[gts055]

It is interesting that many eyepieces with "extended eyerelief " use what is effectively a barlow built in to the eyepiece. Vixen and Televue and chinese equivalents use this system. Good information is at http://www.televue.com/engine/TV3b_page.asp?id=123&Tab=_con
Great to read there are still a few who use an eyepiece :) Mark

[bigjoe]

Hi Rick .

The raw optical performance of many stardard plossls and orthoscopics say, as has been mentioned, or even that 9mm Bintel/GSO plossel that comes with a lot of GSO dobs, it's central sharpness, is probably just as good as anything out there! I know as I have used and compared it many times with all my exotics!

People like myself and Alex, Profiler, Bill Paolini, Don Pensack esp, etc, know, as we have used and tried a lot of exotic eyepieces , and can thus give you some advice before plonking down your hard earned cash;You'll pay a hell of a lot more just for AFOV, and comfort!

Cheers bigjoe.:)

[AstralTraveller]

Not that comfort and afov are to be sneezed at. My 5mm ortho gives great images but who want to observe with their eye frequently touching the eye lens? I don't mind narrow afov for planets and the moon but for DSOs wide afov is sooo nice.

[bigjoe]

[QUOTE=AstralTraveller;1228489]Not that comfort and afov are to be sneezed at. My 5mm ortho gives great images but who want to observe with their eye frequently touching the eye lens? I don't mind narrow afov for planets and the moon but for DSOs wide afov is sooo nice.[/QUOTH

How true David. In reality, after some time mashing my eyeball against an ortho, I find I will soon enough go back to that delos/delite/Nagler etc.

Sometimes you can only take so much pain and contortioning, just to see little to no extra!

And yes, sometimes that extra price you pay for widefield will be worth it esp, if your showing someone else unskilled that object!


Just ask my wife she loves Deloi!!


PS: Shes sending me bankrupt!!!:lol:

bigjoe.

[Rick Parrott]

Thanks all, there is some good info here!:thanx: