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Equipment Discussions >> Eyepieces

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GlennLeDrew
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Re: What Field of View for Your Eyepieces new [Re: zjc26138]
      #5610802 - 01/07/13 07:47 PM

Rob,
You mentioned that it's been said that the Ethos is "better than it should be." A friend has both the 13 Nagler and 13 Ethos, and has compared them in his 14" SCT. He also says the Ethos is a somewhat better performer. (Incidentally, I have a pair of 13 Ethoi for my binos.)

I'm not sure I would fully credit the seeming better performance to optics and coatings. For some years I've noted that without fail, for the observation of the faint fuzzies, a wider apparent field seems to improve visibility. My provisional, half-formed hypothesis considers that the visual system processes the image in a kind of Fourier-like, wavelet deconvolution. Having a larger circle of imagery on the retina allows to process at even longer angular wavelength, further improving edge detection on larger, low contrast features.

Again, this is merely a working theory of my own.


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gnowellsct
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Re: What Field of View for Your Eyepieces new [Re: Erik Bakker]
      #5610814 - 01/07/13 07:54 PM

Quote:

My preference is around 70 degrees for most of the observing I do. I find this AFOV both wide enough AND very comfortable for eye positioning. For low power viewing, I use the good old 20 T2 and 22 T4 Naglers.

Incidentally, the best eyepieces I have found for medium power observing are the 16.7 and 12.8 mm 69 degrees AFOV Carl Zeiss eyepieces. What these do on open clusters and nebulosity is quite special. When I first tried the 16.7 mm in my 4" f/8 fluorite on the Double Cluster, I was stunned by the purity, colors and brightness of the stars over any other eyepiece I've ever owned. And it is such a relaxing, natural view. Below is a picture of these eyepieces with the required Zeiss 2" Astro-adapter.




Is it a 16.7 or a 16.8? I thought it was 16.8. I have one of those. It's a nice eyepiece but I wish there were an XW17 instead.

Anyhow it's paid for.

I have found that I am pretty happy with 70 degrees, but I do have a Leitz 88. My eyepiece collection can be characterized as the un-Televue alternatives, though I have a Pan 24 which comes in handy from time to time.

Greg N


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turtle86
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Re: What Field of View for Your Eyepieces new [Re: GlennLeDrew]
      #5611140 - 01/07/13 11:14 PM

Quote:

Rob,
You mentioned that it's been said that the Ethos is "better than it should be." A friend has both the 13 Nagler and 13 Ethos, and has compared them in his 14" SCT. He also says the Ethos is a somewhat better performer. (Incidentally, I have a pair of 13 Ethoi for my binos.)

I'm not sure I would fully credit the seeming better performance to optics and coatings. For some years I've noted that without fail, for the observation of the faint fuzzies, a wider apparent field seems to improve visibility. My provisional, half-formed hypothesis considers that the visual system processes the image in a kind of Fourier-like, wavelet deconvolution. Having a larger circle of imagery on the retina allows to process at even longer angular wavelength, further improving edge detection on larger, low contrast features.

Again, this is merely a working theory of my own.




Glenn, thanks for your post. Your working theory sounds very promising, and definitely more specific than my vague "larger apparent view gives the brain and retina more to work with". Aside from the brief comparisons I mentioned in my previous post, I haven't really attempted to compare in any systematic way how DSO's look through eyepieces sharing the same focal length but having different AFOV's. (As an aside, I would be very interested in hearing of such comparisons as between a 14mm 82 degree ES and 14mm 100 degree ES.) But my overall observing experience has been much the same as yours, that a wider apparent field seems to improve visibility of faint fuzzies.


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Starman81
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Re: What Field of View for Your Eyepieces new [Re: gnowellsct]
      #5611244 - 01/08/13 12:22 AM

I like 68-72, 82 and 100 degree EPs. They are all enjoyable and are like different gears, not necessarily better or worse, just different. However, as someone with significant astigmatism, eye relief is a constraint for me, personally. Therefore, the Pentax XWs take precedence as they can deliver exiquisite views and all that sweet eye relief. I am also a fan of the Type 4 Naglers (especially the 22mm) as they have more ER than other 82* EPs. The 100* EPs are only possible thanks to DIOPTRX (13 Ethos) and small exit pupil when barlowed with 1.5x/2x (ES100 9mm). So unless I am compelled due to other factors to sell off my EPs, I definitely see myself keeping at least one 82* and one 100* EP in the lineup just to have those different gears to switch to when I feel like it.

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Jeff Morgan
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Re: What Field of View for Your Eyepieces new [Re: JayinUT]
      #5611250 - 01/08/13 12:27 AM

I'm with you on this Jay - the Naglers are nice, but the 70 degree class of eyepieces offer the most comfort for extended observing sessions.

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skullpin
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Reged: 03/13/09

Loc: Edmonton, Alberta, Canada
Re: What Field of View for Your Eyepieces new [Re: Jeff Morgan]
      #5611375 - 01/08/13 05:29 AM

70, 82, 100, 110, 120.

So far 90 is missing! My Tak UW 7 is very easy to use for eye placement, does not black out, and the whole field is viewable with a crisp field stop. Only wish it was a "volcano" shape rather than "coke-can".

Docter 12.5 and Kasai XWV 32 are both 84 degrees and super comfortable.

Keith


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gnowellsct
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Re: What Field of View for Your Eyepieces new [Re: skullpin]
      #5611623 - 01/08/13 10:00 AM

Quote:

70, 82, 100, 110, 120.

So far 90 is missing! My Tak UW 7 is very easy to use for eye placement, does not black out, and the whole field is viewable with a crisp field stop. Only wish it was a "volcano" shape rather than "coke-can".

Docter 12.5 and Kasai XWV 32 are both 84 degrees and super comfortable.

Keith




88 is missing...


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BillP
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Re: What Field of View for Your Eyepieces new [Re: gnowellsct]
      #5612125 - 01/08/13 03:03 PM

Quote:

Quote:

70, 82, 100, 110, 120.

So far 90 is missing! My Tak UW 7 is very easy to use for eye placement, does not black out, and the whole field is viewable with a crisp field stop. Only wish it was a "volcano" shape rather than "coke-can".

Docter 12.5 and Kasai XWV 32 are both 84 degrees and super comfortable.

Keith




88 is missing...




Meade 4000 UWAs have 84 degrees, so 84 is missing.

Nikon HWs have 102 degrees, so 102 is missing

Let's not forget the Pans at 68

Edited by BillP (01/08/13 03:03 PM)


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David Knisely
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Re: What Field of View for Your Eyepieces new [Re: Sarkikos]
      #5612161 - 01/08/13 03:23 PM

Quote:

David,

Quote:

Otherwise, the field is just "there" and I don't think about it all that much (except to really appreciate it when hunting small faint objects in my undriven 14 inch Dob at 135x (14mm ES100 eyepiece) with a whopping true field of 44.7 arc minutes).




I obviate the advantage of a super wide field eyepiece for finding faint fuzzies by making sure my 15x70 finder scope is very closely aligned with the main scope. Then I just look for the location of the object in the finder scope as indicated on SkySafari Pro. I don't need to see the object itself in the finder scope. Nearly everytime the DSO will appear near center of field even in moderately high-power eyepieces in the main scope.

Mike




"Obviate"? Not when you are hunting (and more importantly, trying to identify) 15th magnitude and fainter galaxies that are *all* less than two arc minutes across inside a large rich galaxy cluster! Then, the finder is not all that relevant. I can easily use my Telrad alone to get the scope on such a group, but for tracking down individual galaxies inside, well, that is quite a bit different. With the big Hercules galaxy cluster (Abell 2151) for example, using the 14mm ES100 eyepiece, I have the power I need (135x) to get the scale up to begin to see them, but I also have the field I need to get more than a handful in the field at any one time (along with the rather widely-spaced field stars I need for reference in identifying all of them). In fact, with my ES100 eyepiece, I can see around 50 galaxies in that cluster within the 44.7 arc minute field that the eyepiece provides. There are several sub-groups of galaxies within that big but spread-out galaxy cluster which I made notes on, and the wide field meant that with my un-driven 14 inch Dob, there would be time enough to take a look and examine the plot of them in Megastar without them getting lost due to drift as I went back and forth between my charts and the eyepiece. To each his own, but for me, I am darn glad I got that 100 degree field eyepiece! Clear skies to you.


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Scanning4Comets
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Reged: 12/26/04

Loc: Ontario, Canada
Re: What Field of View for Your Eyepieces new [Re: David Knisely]
      #5612193 - 01/08/13 03:40 PM

Quote:

"Obviate"? Not when you are hunting (and more importantly, trying to identify) 15th magnitude and fainter galaxies that are *all* less than two arc minutes across inside a large rich galaxy cluster! Then, the finder is not all that relevant. I can easily use my Telrad alone to get the scope on such a group, but for tracking down individual galaxies inside, well, that is quite a bit different. With the big Hercules galaxy cluster (Abell 2151) for example, using the 14mm ES100 eyepiece, I have the power I need (135x) to get the scale up to begin to see them, but I also have the field I need to get more than a handful in the field at any one time (along with the rather widely-spaced field stars I need for reference in identifying all of them). In fact, with my ES100 eyepiece, I can see around 50 galaxies in that cluster within the 44.7 arc minute field that the eyepiece provides. There are several sub-groups of galaxies within that big but spread-out galaxy cluster which I made notes on, and the wide field meant that with my un-driven 14 inch Dob, there would be time enough to take a look and examine the plot of them in Megastar without them getting lost due to drift as I went back and forth between my charts and the eyepiece. To each his own, but for me, I am darn glad I got that wide-field eyepiece! Clear skies to you.

--------------------
David W. Knisely . . . . . . "If you aren't having fun in this hobby, you aren't doing it right."




That's awesome David!

How long do you dark adapt before checking that kind of stuff out? ...and what is the limiting mag of the skies you saw that in?

Cheers,


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Sarkikos
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Re: What Field of View for Your Eyepieces new [Re: David Knisely]
      #5612195 - 01/08/13 03:41 PM

David,

Well, I'll have to keep that in mind when I upgrade to a 14" Dob!

So far, though, I've haven't seen any advantage to using a super wide field - and I have two of them - to a good optical finder that's closely aligned to whatever decent eyepiece I have in the focuser of the main scope. If you have a good Zoom eyepiece, it's even better since you can dial in the optimum magnification and contrast to bag faint fuzzies or see structure in the brighter ones.

Mike


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David Knisely
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Re: What Field of View for Your Eyepieces [Re: Scanning4Comets]
      #5612209 - 01/08/13 03:54 PM

Quote:

Quote:

"Obviate"? Not when you are hunting (and more importantly, trying to identify) 15th magnitude and fainter galaxies that are *all* less than two arc minutes across inside a large rich galaxy cluster! Then, the finder is not all that relevant. I can easily use my Telrad alone to get the scope on such a group, but for tracking down individual galaxies inside, well, that is quite a bit different. With the big Hercules galaxy cluster (Abell 2151) for example, using the 14mm ES100 eyepiece, I have the power I need (135x) to get the scale up to begin to see them, but I also have the field I need to get more than a handful in the field at any one time (along with the rather widely-spaced field stars I need for reference in identifying all of them). In fact, with my ES100 eyepiece, I can see around 50 galaxies in that cluster within the 44.7 arc minute field that the eyepiece provides. There are several sub-groups of galaxies within that big but spread-out galaxy cluster which I made notes on, and the wide field meant that with my un-driven 14 inch Dob, there would be time enough to take a look and examine the plot of them in Megastar without them getting lost due to drift as I went back and forth between my charts and the eyepiece. To each his own, but for me, I am darn glad I got that wide-field eyepiece! Clear skies to you.

--------------------
David W. Knisely . . . . . . "If you aren't having fun in this hobby, you aren't doing it right."




That's awesome David!

How long do you dark adapt before checking that kind of stuff out? ...and what is the limiting mag of the skies you saw that in?

Cheers,




I generally don't start going after the really faint stuff until about 45 minutes after I got into the dark. I use that time interval to tweak things like collimation or to do a little "sight seeing" on some brighter and more familiar favorites in the night sky. My regular dark sky site has a typical zenith limiting magnitude of between 6.4 and 6.8, so it is fairly dark. Once I got my 14 inch, galaxy clusters started to get a lot more attention from me, even if they aren't exactly spectacular. The challenge is to ID a lot of the really tiny faint ones that are impossible to see at lower powers and are still a challenge even when you kick the power up a bit. I really like viewing the small "halo" of tiny faint galaxies that swarm around the two giant elliptical galaxies (NGC's 4889 and 4874) in Abell 1656 in Coma Berenices. It makes you really appreciate how big space really is. Clear skies to you.


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John F
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Re: What Field of View for Your Eyepieces new [Re: JayinUT]
      #5613104 - 01/09/13 03:21 AM

For most wife field/deep sky observing I find a 65 to 70 degree apparent field to be both very comfortable to observe with an more than sufficient for many if not most objects I might be viewing.

That said, I now mostly use 100-degree eyepieces for deep sky monoviewing. There are several reasons for that. First, I find the image quality of the Ethos eyepieces to be superb. Second, I don't wear glasses when observing and the 15mm of eye relief of the Ethos series is ideal for me. Third, even if I'm looking at an object/field that doesn't require really ultra wide true/apparent field to encompass and nicely frame it, I just ignore the outer parts of the field and concentrate on the center where the object it. It doesn't bother me to "waste" field in this way.

Fourth and most important. For certain objects and/or wide rich field targets in the Milky Way, a 100-degree can provide breathtaking views which a 70 (or even 80-degree) field eyepiece can't match. So it is nice to have an eyepiece that can provide those views when they're aimed at the right targets as well as perform very well for most other functions I need to use an eyepiece for. About the only object I don't like using Ethos eyepieces on is the Moon at higher powers (i.e., 100x & above).

For binoviewing I have tried using pairs of 13mm & 10mm Ethos eyepieces and found them spectacular in some respects but physically uncomfortable at least for me to observe with on the other so I don't use them for that. Another reason I prefer the Panoptics and T5/T6 Naglers for binoviewing is their much smaller size and lighter weights.

John Finnan


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Shneor
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Re: What Field of View for Your Eyepieces new [Re: Sarkikos]
      #5614021 - 01/09/13 04:23 PM

Quote:

Shneor,

Why do you keep both the ES 100 9 and ES 120 9? Is it just that the ES 100 9 is lighter and more convenient for your smaller scopes?

Mike



Exactly - the 120° is too heavy for my 6" Meade f/5!

Clears,


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Sarkikos
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Re: What Field of View for Your Eyepieces new [Re: Shneor]
      #5614183 - 01/09/13 06:03 PM

Makes sense to me.


Mike


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GeneT
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Re: What Field of View for Your Eyepieces new [Re: JayinUT]
      #5614258 - 01/09/13 06:40 PM

I spent some time with a friend's 13mm Ethos and compared the views in my 12 Nagler. I just liked the Nagler better. Moving to mid and short focal length eyepieces, I am pleased with my Delos eyepieces. I own the 14, 10, 8 and 6 Delos. I kept my 4mm Radian for the once in a great while time I need that much magnification.

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Starman81
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Re: What Field of View for Your Eyepieces new [Re: GeneT]
      #5614327 - 01/09/13 07:19 PM

Quote:

I spent some time with a friend's 13mm Ethos and compared the views in my 12 Nagler. I just liked the Nagler better. Moving to mid and short focal length eyepieces, I am pleased with my Delos eyepieces. I own the 14, 10, 8 and 6 Delos. I kept my 4mm Radian for the once in a great while time I need that much magnification.




Gene, I cannot fault you; the views both provide are pretty awesome. I love the ER of the Type 4's.


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Knygathin
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Reged: 12/31/09

Re: What Field of View for Your Eyepieces new [Re: Starman81]
      #5648930 - 01/28/13 06:37 PM

Tele Vue keep topping themselves with ever more spectacular eyepieces. Do you think there eventually will be a 180 degree AFOV eyepiece, perhaps with a concave shaped lens that you dip your eye into?

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faackanders2
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Re: What Field of View for Your Eyepieces new [Re: Sarkikos]
      #5649311 - 01/28/13 09:37 PM

Quote:

David,

Well, I'll have to keep that in mind when I upgrade to a 14" Dob!

So far, though, I've haven't seen any advantage to using a super wide field - and I have two of them - to a good optical finder that's closely aligned to whatever decent eyepiece I have in the focuser of the main scope. If you have a good Zoom eyepiece, it's even better since you can dial in the optimum magnification and contrast to bag faint fuzzies or see structure in the brighter ones.

Mike




Multiple objects are when wide TFOV pays off. Able to see more objects in same FOV (Markarians Chain, M31/M32/M110, Leo's Triplet, More of Viel or North American, or M45, or M44, etc) and mor time when you can see multiple planets or moving obects )comets, asteroids) within same FOV of each other and or other DSOs.

Even with a camera I often find the wide angle lens more useful than the higher power ones.


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faackanders2
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Re: What Field of View for Your Eyepieces new [Re: BillP]
      #5649326 - 01/28/13 09:47 PM

Quote:

Quote:

So I take it then that those who prefer the 'smaller' AFoVs clap on a pair of blinders when naked eye gazing... If not, how is a 100 degree field too expansive, when the eye's inherent field approaches 180 degrees?




Good one! However, naked eye, when I move my eyeball to the right to look on-axis at what was off-axis a second ago, my vision does not black-out or have a good amount of lateral color now on-axis until I get my head repositioned just right for the lateral viewing. And when I naked eye gaze to the right, the far left of my peripheral vision does not go away. Plus, when I gaze naked eye to the far right, I am not greeted with ubber-pincushion. All these are common traits in ultra-wides. Some people do not experience many of these, but many many do. Our eye's physiology is different from person to person. At any rate, its a very "unnatural" experience just gazing right in an ultra-wide. Takes some getting used to. For many, not worth the effort as just feels too unnatural. Plus, as said before, noticing unique asterisms in the FOV is much more difficult when one has to gaze around...they just are not as obvious. 70 degree eyepieces seem to tame all the devils much better than wider FOVs, plus still provide a very engaging space-walk like experience as well. Best of all worlds. If others don't have these issues...more power to them. But for me...70 is best and I feel I am missing absolutely nothing since I sold all my 82s...I actually feel things have improved quite a bit

I still do have 2 82s in the stall, but consider them "novelty" eyepieces, like the 28RKE. Great for once in a while because they give a different perspective, but not good as an every day thing.




with my 10mm 100 AFOV Ethos in my 17.5 f4.1 dob they make a full moon look like 7 ft tall an arm's reach in front of you with very little margin all around. Everyone who looks normall has they jaw hit the ground. That is what 100 AFOV can do!

What impresses everyone the most (biginners and experienced alike) is everyone know how large the moon is, so they know how much it is blown up. Keeping the entire sphere makes it look more natural/uncropped.


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