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3.5mm Delos vs. 3.5mm Pentax XW

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#76 ausastronomer

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Posted 30 October 2024 - 06:08 PM

Well, I decided to bite the bullet and order the Pentax 3.5mm. US $243 shipped, snap up this deal while it lasts, last eyepiece in stock too. Don't have much to lose I figure. Ain't gonna come across any reasonably price Ethos or Delos any time soon it seems. 

 

You will be very happy with your new eyepiece and in the process saved a lot of $$$$ over some of the other options.

 

Cheers


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#77 HellsKitchen

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Posted 31 October 2024 - 06:34 AM

You will be very happy with your new eyepiece and in the process saved a lot of $$$$ over some of the other options.

 

Cheers

 

Thanks mate. Straight up half the cost of a Delos, was a no brainer really. Considered the Nagler aswell, but was worried about losing the immersion factor, which I've come to realise is an important part of the viewing experience for me. The resulting magnification will be very close to a 9mm Morpheus-2.5x Powermate and 12.5 Morpheus-5x Powermate so will be interesting to compare the views. 


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#78 ji4m

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Posted 31 October 2024 - 10:26 AM

Remove the Delos eyecup and clean the barrel and collet with alcohol.

Reassemble.

Once you've found the right placement for the eyeguard in the field, note the line on the side of the eyepiece that corresponds to your perfect position in case the eyeguard moves.

Remove the eyepiece from the focuser and "gorilla tighten" the two parts of the eyecup using both hands and a lot of strength.

I experienced this movement on the Delites (same eyeguard design) until I did this, and the eyeguard got tight enough it would have taken a hammer to move it.

 

There may be a machining variance from eyepiece to eyepiece, but after I did this I could even remove the super-tight Delite bottom caps without moving the eyeguard.

I did, however, change the bottom eyecaps on the Delites because they were just too tight.  A cap should come off easily, yet stay on.

I think rubber caps go on and off more easily, but they also tend to be looser, and not stay on well.  Plus, rubber caps on the bottoms can be pressed into contact with the bottom lens in the eyepiece,

so they are not desirable for eyepieces with lenses close to the bottom of the eyepiece.

Thank you for the suggestion.  I'll give it a go.

"Gorilla tighten".  Cool.  I like that.  I'm old so I will "Conan" it tight.smile.gif



#79 csrlice12

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Posted 31 October 2024 - 10:36 AM

While I like the optics, having to choke an eyepiece till it stops moving just kinda creeps me out...



#80 CrazyPanda

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Posted 31 October 2024 - 11:09 AM

I experienced this movement on the Delites (same eyeguard design) until I did this, and the eyeguard got tight enough it would have taken a hammer to move it.

 

I think the newest batch of DeLites has changed the grippy-ness of the eye guard. My latest 18.2 DeLite's eye guard is annoyingly hard to move even when fully loosened. I like to keep the eye guards collapsed so save room in the case, and just adjust it on the way up to the focuser. I may have to swap it out for one of my older 18.2 DeLite's eye guards.

 

When you cinch it down tight, it absolutely doesn't move.



#81 mountain monk

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Posted 31 October 2024 - 11:09 AM

It is amazing to me how the XW has sustained its reputation over the years in the face of so much competition. The 3.5mm up to the 10mm remain for me the easiest eps to use even though I prefer the wider views of the Morpheus and Ethos. I tried the Nikon SW, the Delos, and the DeLite, but they are all going or gone. The XW Buddha was prescient.

 

Dark skies.

 

Jack


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#82 csrlice12

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Posted 31 October 2024 - 12:35 PM

Imagine being in the Pentax board room when you are told, "design us a telescope eyepiece that will be top of the line for years to come, here's a really nice budget to do so".


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#83 davidgmd

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Posted 31 October 2024 - 02:46 PM

Thank you for the suggestion.  I'll give it a go.

"Gorilla tighten".  Cool.  I like that.  I'm old so I will "Conan" it tight.smile.gif

  

LOL, which Conan?

  

  

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EMG5hmvU0AAdJaP.jpg


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#84 25585

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Posted 31 October 2024 - 03:09 PM

Gimme Xena any day 

 

 

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#85 civis

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Posted 13 April 2025 - 10:14 AM

3.5mm Pentax is a decent eyepiece, but difficult to find right eye position to avoid "kidney" effect, and you need hell of a scope to support such magnification. So far my refractors really sucked with 3.5mm, 5mm is max usable.


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#86 25585

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Posted 13 April 2025 - 05:54 PM

3.5mm Pentax is a decent eyepiece, but difficult to find right eye position to avoid "kidney" effect, and you need hell of a scope to support such magnification. So far my refractors really sucked with 3.5mm, 5mm is max usable.

I found that effect with the 3.5, 5 & 7mm XWs (Delos & Delites similar). Not so with Vixen LVWs (3.5, 5 & 8mm), Pentax Xand Nikon NAV SWs (5 & 7mm) though. No problem in XW70 range 10mm =/> (apart from Delos & Delites, though latter OK 13mm & longer). So what is/is not in the optics/optical designs, that makes some eyepieces easier than others to use?


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#87 John Huntley

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Posted 13 April 2025 - 08:12 PM

I had some problems with the XW's and eye placement, until I bothered to read the instruction manual !

 

From that I learned that, for me as a non-glasses wearer when observing, the best position for the XW eye cup (ie: the whole top section of the eyepiece) was in it's uppermost position. That made all the difference for me and I went on to acquire the 10mm, 7mm, 5mm and 3.5mm Pentax XW's and use them often with my scopes.

 

I have owned the 4.7mm and 3.7mm Ethos SX eyepieces plus the Nagler T6 5mm and 3.5mm, and with the exception of the field of view, the Pentax XW's performed at least as well as the Tele Vue alternatives, I felt smile.gif


Edited by John Huntley, 13 April 2025 - 08:14 PM.

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#88 25585

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Posted 14 April 2025 - 07:23 AM

Wearung glasses, I have the eyecups raised a smidgeon on my XWs 30 and 40, 14 and 20 are just right at lowest, 10 at lowest is just enough to see the whole FoV.




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