184 replies to this topic

[davidgmd]

That’s why they make more than one flavor of ice cream: folks have different preferences whether talking about glasses or eyepieces.

Some like 100*, some don't. 

  

I was happy with my 72* Delos and didn't think I cared much about 100* until I tried the 6 mm Ethos. I feel like going to 82* with the N7 would be a step backwards.

For longer focal lengths, where I'd need my glasses to correct astigmatism, the Ethos aren't really an option. That's where the N7s fit in.

Edited by davidgmd, 30 May 2025 - 08:14 AM.

[Dobs O Fun]

Ok.

Let's get back to Would You Replace Your Ethoi with Nagler Type 7's?.

Please back to topic.

[25585]

People who bought Ethos, can or could do without the longer eye relief that T7s offer, when the former were first bought. So one reason to change might be needing to wear glasses, therefore there is relevance in the thread topic to the discussions above.

 

But its wider than just the two TV ranges, as others in other threads have stated the need to change some or all of their eyepieces, as vision needs change over time.

[MikeTahtib]

In one of my Anthropology classes, we determined that one of the class's students was an almost perfect replica of a Homo erectus.

He even had one large brow ridge spanning both eyes.

His eyes were so deeply set he's need at least 35mm of eye relief to even contemplate using glasses. 

Did he leave that class questioning everything he had experienced in life up to that point?  Did he get a new nickname?  

[Starman1]

Did he leave that class questioning everything he had experienced in life up to that point?  Did he get a new nickname?  

It favored the idea that if you took a Homo sapiens neandertalensis, gave him a shave and haircut, and put him in a suit and tie, that he could walk down the streets of Manhattan without notice.

In that class of 20 students, brain capacity ranged from 1150cm³ to 2700cm³.  The range of human variation is huge.

 

Which relates to the eye relief needed for eyepieces.  Here on CN we have people who only need 12mm of eye relief to use glasses, and others who need >20mm.  And I suspect if we actually took measurements, the range would be even wider.

The need for eye relief led me to sell my Ethos eyepieces longer than 7mm, and makes the T7 Naglers very attractive.  I suspect I'm not alone in that.

[Maximus001]

It favored the idea that if you took a Homo sapiens neandertalensis, gave him a shave and haircut, and put him in a suit and tie, that he could walk down the streets of Manhattan without notice.

In that class of 20 students, brain capacity ranged from 1150cm³ to 2700cm³.  The range of human variation is huge.

 

Which relates to the eye relief needed for eyepieces.  Here on CN we have people who only need 12mm of eye relief to use glasses, and others who need >20mm.  And I suspect if we actually took measurements, the range would be even wider.

The need for eye relief led me to sell my Ethos eyepieces longer than 7mm, and makes the T7 Naglers very attractive.  I suspect I'm not alone in that.

+1 to the above but for some reason I still love and use my E17 and can’t part with it. 

[Starman1]

I understand.  It was that way for me with the 10mm Ethos.

But when the star images started looking like the f/5 edge of field images in this illustration when they were in the center of the field and only looked like the f/10 images when wearing glasses,

it was time to part with the eyepiece.  It went to a good home.

And I splurged on an 11mm Apollo to take its place, and the 85° field seems plenty wide.

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[Procyon]

Those are called UFO aberrations. If you see em, time to get glasses. 

[thecelloronin]

Observing with glasses:

• the edges of the fields in eyepieces will be sharper and better focused.

Why is this?

[Starman1]

Why is this?

Glasses correct refraction, which tightens up focus, and astigmatism that comes from the eye is gone, leaving only slight astigmatism from the eyepiece, if any.