14 replies to this topic

[Princess Leah]

Good day Cloudynighters.

 

I enjoy wide views as much as anyone - probably a bit more than most.

However this eyepiece is not one I reach for at very low powers and I am not sure why.

 

Whether using my 80 F6 triplet, or my 102/F5 I tend to ignore this eyepiece. I prefer instead to use a 30mm UFF or even a five element 38mm 70 degrees with soft edges. This is despite the 24mm 82 being well corrected to the edge.

 

However in my 120 F8.3 I really like using the 24mm 82 degrees.

 

In the shorter scopes the 24mm 82 ( I'm actually sure Celestron got it right with the Axiom and it's 23mm) gives around 4 degrees. This extra wide views seems to put some kind of pressure on the eyepiece and I feel the view is a bit unnaturally distorted.

 

Is distortion in a 82 degree EP more obvious with decreased magnification/wider FOV?

I have other shorter focal length 82 degrees EPs and I don't have any issue with them, although they provide higher magnifications.

 

Foot note. I believe the ES fieldstop is accurate. However I think the EP is approximately 23mm 84 degrees and not 24mm 82 degrees.

[Ernest_SPB]

...and I feel the view is a bit unnaturally distorted.

What kind distortion are you talking about? Pincushion distortion? Yes, it is a known attribute of this (and most other 82) eyepiece.

[Princess Leah]

Thanks Ernest for your reply.

 

Yes pincushion.That sounds accurate.

However I'm wondering why I don't see it at higher magnifications.

Would that be because at higher magnifications I'm viewing at F8.3 with a different refractor. A more gentle light cone entering the eyepiece.

Or is it because the FOV is less?

 

Does pincushion get worse with Ethos and other 100 degrees eyepieces?

I can't see how it can be avoided.

Edited by Princess Leah, 06 February 2025 - 09:02 AM.

[Princess Leah]

In other words, the seasickness effect is less noticeable at higher magnifications?

[SeattleScott]

Wider AFOV needs more distortion. The other eyepieces aren’t as wide of AFOV, so they have less distortion.

[Princess Leah]

I mentioned I don't get the problem at higher magnification. Or with my ES 14mm 82 for example.

[SeattleScott]

I mentioned I don't get the problem at higher magnification. Or with my ES 14mm 82 for example.

Are you panning around with your 14mm?

Some (like Don) don’t like the distortion in Nikon SWs. However I still got three of them, 5, 7 and 10. Why? Because I don’t pan around at those focal lengths. I pan around at low power to find a target, then just stay on the target once I find it. If you aren’t panning around, distortion isn’t an issue.

[csrlice12]

In my 10" f4.7 dob, the ES82 24mm was impressive...50X with M42 or M8 in the fov were real treats.  It's the only eyepiece I regret selling.

[vrodriguez2324]

When I had it I used it in my 8 inch f/5 for just about 2 degrees. I really liked it and to me it was very immersive. 

 

Believe it or not I used it with the 4x Powermate as the next step down from the ES 9 100. You could use it as a baseball bat to hit dingers. 

 

Maybe at 4 degrees the presentation would be different? 

 

I no longer have the Powermate, the 30mm ES 82, 24mm ES 82, or the ES 9 100. I probably miss the 24 the most. 

 

 

 

Attached Thumbnails

• 
• 

[Princess Leah]

I already said it's fine at 2 degrees.

 

Scott makes a very good point. At low magnification - more panning!

However I don't think that's the full picture.

I use the 14mm terrestrially and there is little feeling of obvious distortion at infinity.

There is with the 24/82.

 

Personally I feel there is a 'plane' or axis in the night sky that gives form to our image. There is an understood curvature even when viewing at 4 degrees.

 

At two degrees the image becomes 'flat' and the understood curvature is no longer present. Distortion becomes less of a problem.

 

With binoculars this form and curvature is even more obvious. It's something I enjoy very much.

 

 I realise this perhaps makes little sense scientifically but it is a true real world experience. Perhaps the creator has given form and content to the night sky, via an imaginary plane, viewed from our perspective on earth.

[EsaT]

Yes pincushion.That sounds accurate.

However I'm wondering why I don't see it at higher magnifications.

Would that be because at higher magnifications I'm viewing at F8.3 with a different refractor. A more gentle light cone entering the eyepiece.

Or is it because the FOV is less?

Lower magnification/wider view fits more stars into view.

That certainly makes geometric distortions in image more easy to spot when turning telescope and stars move across the view.

When there's less stars/farther away from each others in image geometric distortion becomes harder to spot.

[Princess Leah]

Lower magnification/wider view fits more stars into view.

That certainly makes geometric distortions in image more easy to spot when turning telescope and stars move across the view.

When there's less stars/farther away from each others in image geometric distortion becomes harder to spot.

Interesting so are we able to make sense of the sky geometrically even when viewing a small area of 3-4 degrees? I thought perhaps this was just my imagination:)

 

I don't see less stars a higher magnification. For example using a 14mm 82 might even reveal more stars in an urban setting due to smaller exit pupil/increased contrast.

Edited by Princess Leah, 07 February 2025 - 04:46 AM.

[EsaT]

Interesting so are we able to make sense of the sky geometrically even when viewing a small area of 3-4 degrees? I thought perhaps this was just my imagination:)

 

I don't see less stars a higher magnification. For example using a 14mm 82 might even reveal more stars in an urban setting due to smaller exit pupil/increased contrast.

Brighter more easily detactable stars are likely the ones whose relative position/distance changes trigger vision more easily to detecting geometric distortion.

Our vision system isn't exactly some precise computer along with "detector/sensor" having blind spot etc.

[SeattleScott]

Interesting so are we able to make sense of the sky geometrically even when viewing a small area of 3-4 degrees? I thought perhaps this was just my imagination:)

I don't see less stars a higher magnification. For example using a 14mm 82 might even reveal more stars in an urban setting due to smaller exit pupil/increased contrast.

Remember though, distortion is only noticeable when panning around. It isn’t like you have memorized where every star in the sky is supposed to be. When the field isn’t moving, how would you detect distortion? You won’t. It can only be detected when you are moving the scope around.

I suspect you use the 24mm to pan around and hunt for targets. You probably mostly use the 14mm once you have located and centered the target.

Panoptics are all 68 AFOV and all have similar distortion characteristics. But why do people mainly complain about the 24mm having distortion? Because they are panning around with it.

[astroclint]

In my 10" f4.7 dob, the ES82 24mm was impressive...50X with M42 or M8 in the fov were real treats.  It's the only eyepiece I regret selling.

You could get a maxvision eyepiece.

It is cheaper than the es.

https://www.aliexpre...rch|query_from: