86 replies to this topic

[Procyon]

Be honest with us, you're afraid of the boogeyman and need some light.

Edited by Procyon, 12 May 2025 - 03:11 PM.

[vertigo777]

3 silver, 2 black.

[vertigo777]

Be honest with us, you're afraid of the boogeyman and need some light.

ha.

 

I'm MORE afraid of REAL people than the boogeyman and the boogeyman likes to stay under my bed, he's scare of real people too!

[azure1961p]

I take your choices and opinions seriously considering your experience and the availability to sooo many eyepieces.

 

Gotta ask, when do you use your refractor and is there a set within the list you reserve for the frac?

 

Love that you hashed out your kit and defined pluses and minuses.  

 

Another list, for deepsky would be great; in your experience what were the absolute worst oculars you've comes across?  I'd rule out orthoscopics, plossls and mono's because they are more planetary.

 

Great post my friend.

 

Be well, 

Pete

Edited by azure1961p, 13 May 2025 - 09:38 AM.

[Starman1]

I take your choices and opinions seriously considering your experience and the availability to sooo many eyepieces.

 

Gotta ask, when do you use your refractor and is there a set within the list you reserve for the frac?

 

Love that you hashed out your kit and defined pluses and minuses.  

 

Another list, for deepsky would be great; in your experience what were the absolute worst oculars you've comes across?  I'd rule out orthoscopics, plossls and mono's because they are more planetary.

 

Great post my friend.

 

Be well, 

Pete

My refractor is typically used at my home in LA.

It is used on the Moon, planets, double stars, open and globular star clusters.

I don't even bother with nebulae and galaxies here in the home of Light Pollution Magnus (SQM 16.8-17.8 the normal range).

 

It has seen dark skies, like when I was trying to see if all 650 objects on my *BEST* list were visible.

It helped me winnow that list down to the 503 objects that are on the list:

https://www.cloudyni...orum/?p=9861359

 

I grew to love ultra-wide eyepieces in the '80s, though I used a lot of narrower eyepieces well into the '90s.

By 2010 or so, my eyepiece set consisted solely of 100-110° eyepieces, which is where I'd be today were it not for a growing astigmatism in my eyes.

Today, I can remove my glasses at/around a 1.5mm exit pupil, but any exit pupil larger and I need to wear glasses.

I didn't get along with a DioptRx in the dob for a variety of reasons, so glasses compatibility became paramount.

 

But, in answer to your question, I have some eyepiece requirements for DSO observations:

--ultrawide field so I can observe longer between nudges of the scope, and to provide more context for the objects viewed.

--excellent correction in the outer field to near, if not to, the field stop, i.e. no intrinsic astigmatism, well-controlled lateral chromatic aberration, no dizzying distortion when the field drifts (why I didn't like the Docter/Noblex).

--no obvious edge of field brightening when used in a dry transparent air (I can forgive some when the air is misty).

--sharp star images to right at, or near the field stop.

--good control of internal light scatter, i.e. good contrast

--not extremely heavy (capping the max at 700g)

--compatible with glasses

 

Yes, the eyepieces I use with the 4" apo at times are the 22mm (32x), 12.4mm, 8.9mm, 6.0mm, 4.8mm, 3.7mm (193x).  Here in LA, it's mostly the 3 shorter focal lengths to avoid washed out images.

 

It isn't so much that there are not some fantastic narrower field eyepieces, because there are.  I had a full set of Tele Vue Delites for a while, and they were truly superb, but after a while I realized that I just couldn't live with such narrow field eyepieces, no matter how good they were.  Even when observing planets, I wanted a much longer drift time to observe before nudging the scope.

So, eyepieces below 70-75° are just not on my personal radar now, even though I've owned LOTS of them over the years.

I think it matters how short the focal length of the scope is.  Narrow field eyepieces and short focal length scopes go together fine.

In a Tele Vue NP101, a 32mm Plössl yields a 2.86° true field at 17x, for example.

In a 9.25" SCT, a 32mm Plössl yields a 39' true field at 73x for comparison.

 

Over the years, there have been a number of eyepieces that just didn't mate well with my scopes.  Some standout poor ones were all the eyepieces called "Superview", and the Baader Hyperion 31mm and 36mm.

Those didn't even work well in my f/10 SCT.  Mostly, though, it was just eyepieces that weren't well corrected in the outer field or which had some other characteristic that made them unappealing.

A few examples: 12.5mm Docter UW (distortion), 12.5mm APM Hi-FW (EOFB), 9mm 120° ES (eye lens reflection), 25mm 100° ES (vignetting, astigmatism), 20mm 100° ES (astigmatism), 24mm Baader Hyperion (astigmatism).

I could go on and on.  I've sold hundreds of personal eyepieces for one reason or another.

I'd be really excited about the new Tele Vue Nagler Type 7s were it not for the fact I don't want or need 3 of the 4 focal lengths. 

I'm waiting to see how well the eyepieces I own work in my 16", but that'll take a few months to decide.

[azure1961p]

Don,

 

Thanks for the depthful reply. 

 

I'm curious about "edge of field brightening".  I'm at a loss to understand other than perhaps the lens edges aren't blackened or some lack of baffling, masking or some such.  Now I have to look for it ! Could you explain it fuller?

 

As the deepsky aficiando you are I truly get the interest in the über widefields at 100-110° .  I've still not looked through but I can imagine things like the span of Andromeda M31,32 (110) , M33, the sword of Orion or the big view of M42/43 must be up there with a religious experience.  M13 then, lol, kneel before Zod! Add the full moon In that list.  I envy your kit and now your 16.

 

You're in a good place Don , but you know that.

 

Thanks in advance!

 

Again, the gestalt of 110° spans... I've gotta hit star parties again.

 

Pete

[Starman1]

Edge of field brightening has been a hot topic:

https://www.cloudyni...ld-brightening/

https://www.cloudyni...ry-interesting/

https://www.cloudyni...ld-brightening/

https://www.cloudyni...ic/769375-eofb/

https://www.cloudyni...htening-survey/

https://www.cloudyni...-for-neurotics/

 

How it looks:

https://www.cloudyni...tics/?p=9310999

 

There are many more threads on the subject.  I think most designers aren't aware of it or how to solve it.

But I did have one manufacturer tell me they were aware of it, but did not know how to solve it.

[Procyon]

Hate SAEP (Kidney Beaning, the really annoying type), EOFB and Chromatic Aberration (CA). If I see any of those 3, they're out. 

Edited by Procyon, 14 May 2025 - 02:54 PM.

[Starman1]

Hate SAEP (Kidney Beaning, the really annoying type), EOFB and Chromatic Aberration (CA). If I see any of those 3, they're out. 

Most eyepieces have some lateral chromatic "prismatic" smear, though changing the angle you look through the eyepiece can sometimes eliminate it.

CA on axis, though (like Huygens or Kellner), is a sign of a deficient design.

 

SAEP is present in a lot of eyepieces, but it's a matter of degree as to whether or not you see it.

Generally, it is not seen in really short focal lengths due to the small exit pupils.

But once you get to medium focal lengths, it can be quite annoying. 

[Procyon]

Most eyepieces have some lateral chromatic "prismatic" smear, though changing the angle you look through the eyepiece can sometimes eliminate it.

CA on axis, though (like Huygens or Kellner), is a sign of a deficient design.

 

SAEP is present in a lot of eyepieces, but it's a matter of degree as to whether or not you see it.

Generally, it is not seen in really short focal lengths due to the small exit pupils.

But once you get to medium focal lengths, it can be quite annoying. 

Don, I once saw an aberration I really hated with some 25mm UO Orthos II, it was like CA but with small spikes? Would that be Astigmatism? I see it in very cheap binoculars also. Stars look like an annoying red-greenish color with a small spike, and you can't make it pin point no matter how much you try and fine focus. 

Edited by Procyon, 14 May 2025 - 05:31 PM.

[Starman1]

Don, I once saw an aberration I really hated with some 25mm UO Orthos II, it was like CA but with small spikes? Would that be Astigmatism? I see it in very cheap binoculars also. Stars look like an annoying red-greenish color with a small spike, and you can't make it pin point no matter how much you try and fine focus. 

Astigmatism with concomitant CA.  I see that in a lot of binoculars, too, even expensive ones.

My old 10x50 Fujinon FMT-SXs were free of that (individual eye focus).  I should never have sold them.  Hindsight is 20/20, as they say.

I could buy another pair, but now they are only available with rubber cover, which deteriorates.

[azure1961p]

Edge of field brightening has been a hot topic:

https://www.cloudyni...ld-brightening/

https://www.cloudyni...ry-interesting/

https://www.cloudyni...ld-brightening/

https://www.cloudyni...ic/769375-eofb/

https://www.cloudyni...htening-survey/

https://www.cloudyni...-for-neurotics/

 

How it looks:

https://www.cloudyni...tics/?p=9310999

 

There are many more threads on the subject.  I think most designers aren't aware of it or how to solve it.

But I did have one manufacturer tell me they were aware of it, but did not know how to solve it.

Thanks Don, I had no idea it's that much of a topic.  I come and go with CN. Clearly I missed this!

 

Pete