Eyepiece Designs and Sacrifices

[alan potts]

Sharpness isn't everthing look at the Meade QX range. Many people have to buy eyepieces that will not be sharp across a full FOV in a fast scope because ones that are sharp are very costly.

Alan

[Stargazer_00]

If I had to pick one thing above all else it'd be contrast. every time.

[Naemeth]

Going over this many times, they all have uses. For me though, a soft eyepiece in sharpness is a real disappointment on objects like the Moon - one I'd do my best to avoid, when I look at the moon I want that 'wow' crispness, to be able to see the details in perfect focus is an awesome sight and lack of sharpness spoils the view tremendously! Contrast is very important for DSOs and Jupiter / Saturn, kidney beaning can be annoying too.

[Astrobits]

If you haven't got sharpness then you haven't got fine detail in whatever you are looking at contrast or not. Lack of sharpness will bleed light from one area into others. If the bright areas don't bleed light into adjacent areas then you have got sharpness. High contrast is not necessary to see fine detail, views of the planets are often better in misty/foggy conditions which give low contrast, DSO's are then very difficult/impossible. In very clear skies the planetary views are often terrible because the contrast it there but the sharpness is not, a good time for those DSO's.

Alan, you may well accept some loss of sharpness towards the edges of the field of view but would you accept poor sharpness over the whole field of view, including the centre? I doubt it.

I don't think that it is possible to make an eyepiece that is perfect in only one feature and very bad in all the others. Controlling precisely where the light goes will control many of the other parameters.

For me I can live with acceptable levels of most defects but if it ain't sharp it's useless.

Nigel

[alan potts]

Nigel,

I will not accept a loss of sharpness anywhere in the FOV this is why I have spent so much on good quality eyepieces. I did have a 40mm Aero which was not giving me what I wanted at F 10, so it went and along came a Meade SWA 40mm only to find out the scope needed a litltle collimation work, this was a few years back when I was getting back into it , so to speak. I only had the one scope then. My second scope was the APM, now for me you would have to be a bit soft somewhere to buy one of those and then accept a lack of sharpness, I would have thought it was the major reason for the scope in the first place.

I think what keith is saying it contrast is his number one priority but an eyepiece thatv offered excellent contrast is going to be sharp as well, like my Radians or Delos's, don't know what word you would use for more than one, 'Deli' maybe.

Sounds like an idea for a thread what would the plurals of Ethos and Delos be.

Alan.

[RikM]

Sharpness is so fundamental to an eyepiece that it probably isn't considered an optional characteristic; it is a given. The other characteristics can negate the sharpness in the eyepiece so you (or at least I) give them more consideration.

I think it this is supported by the fact that (to date) nobody voted that sharpness was unimportant.

[Astrobits]

Sharpness is so fundamental to an eyepiece that it probably isn't considered an optional characteristic; it is a given. The other characteristics can negate the sharpness in the eyepiece so you (or at least I) give them more consideration.

I think it this is supported by the fact that (to date) nobody voted that sharpness was unimportant.

I was contemplating this after my last post and you are quite right. Sharpness is being taken as being there anyway and the votes are really for the extra requirements which will differ between the voters.

Nigel