Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Eyepieces

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | (show all)
Scanning4Comets
Markus
*****

Reged: 12/26/04

Loc: Ontario, Canada
Re: Pentax XW versus Delos, an informal comparison new [Re: JustaBoy]
      #6037210 - 08/20/13 07:46 PM

Quote:

AFOV is of course purely a personal preference, 70 degrees appears to be a very popular place to be. Wide fields without unusual and un-ergonomic head or neck contortions in the dark.




I agree that 70° is a nice place to be, however, I use 82-100° eyepieces. I don't have to use any unusual "un-ergonomic head or neck contortions" to see the entire FOV in any of my eyepieces.


Post Extras: Print Post   Remind Me!   Notify Moderator  
coutleef
Post Laureate
*****

Reged: 02/21/08

Loc: Saint-Donat, Quebec, Canada
Re: Pentax XW versus Delos, an informal comparison new [Re: Starman1]
      #6037247 - 08/20/13 08:14 PM



-I don't know what you're talking about. The objects I view don't show colors. Everything is gray. Is this really an issue for anyone except the Moon viewer? I've noticed that a good yellow filter brights out small details on the Moon incredibly. That's not "neutral". Is complete neutrality always good? And is any eyepiece tinted to the degree of even a light filter, or we talking about the difference in degrees of white? Do you still see any hint of coloration after 10 seconds?






Don, but when you look at star clusters, older cluster contain stars with different colors. I found that these colors were more vivid with the XW and delos (as well as the 17 ethos) than with the T6s. Star clusters do have colors (and planetaries have a blue-green tint).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Pentax XW versus Delos, an informal comparison new [Re: Scanning4Comets]
      #6037297 - 08/20/13 08:52 PM

Quote:

I don't have to use any unusual "un-ergonomic head or neck contortions" to see the entire FOV in any of my eyepieces.



Agreed. The usual ergonomic contortions are the ones i use, personally.







Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Pentax XW versus Delos, an informal comparison new [Re: Mike B]
      #6037304 - 08/20/13 09:13 PM

Quote:

Quote:


-Yes, the wider the better. if the eye relief is sufficient, and you have developed the skill of holding the pupil fixed while the head rolls around to look at the edges (say, after several years of using 82 degree eyepieces), who wouldn't prefer a picture window to a pinhole? Especially if it comes with increased sharpness and better star color renditions.




Quote:

-I don't know what you're talking about. The objects I view don't show colors. Everything is gray.




OK, so color is rendered better, or not there at all?

But about this pinhole business. The smallest AFOV in a production eyepiece is about 40 degrees (30 degree on a special order Monocentric from Markus at APM). Even the relatively small Monocentric AFOV is comparable to the AFOV most us experience sitting in their customary seat watching our lovely big screen TVs. If you don't believe it grab a tape measure and do the math.

AFOV is of course purely a personal preference, 70 degrees appears to be a very popular place to be. Wide fields without unusual and un-ergonomic head or neck contortions in the dark.




OK, I can see where it looks like I was being inconsistent.

It is true that colored stars do show up better in certain eyepieces, but it is not, by and large, relevant to the galaxy and nebula viewing I do a lot of. And the tiny amounts of tint often described as "coffee tint" are irrelevant to the observing I do, even colorful nebulae.

You're right about watching TV and viewing angle, but that is really constrained compared to looking out a picture window and an ultrawide eyepiece is closer to the latter. But even a 70 degree field is a bit like a stage where our 30 degree direct vision is more like the spolight that moves from side to side to "see" it all. The only difference is that the wider eyepieces have a larger stage.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Pentax XW versus Delos, an informal comparison new [Re: coutleef]
      #6037333 - 08/20/13 09:30 PM

François,
My observations correspond to yours as well.
I don't think we're talking about tint here, but the ability to see color more easily (or at all). I was a little too flippant in my remark about color, as there definitely are some colors visible through eyepieces, including on planets. And that is, in my opinion, a huge step beyond the minute coloration differences that people here ascribe to various eyepieces.

One test I read said that as the illumination on a white panel lessens that the human eye starts seeing yellows in the white, and that the reason is that we lost our ability to see the ends of the spectrum as illumination reduced, making yellow more prominent. So I wonder if the coloration some viewers see is actually a spectral difference in the light passing through the eyepiece, or merely a reduced transmission? And if it's the spectrum of transmission, if it's attributable to one specific glass type.

Here is something that might answer the question:
http://www.amateurastronomie.com/Astronomie/tips/tips3.htm


Post Extras: Print Post   Remind Me!   Notify Moderator  
ibase
Vendor Affiliate
*****

Reged: 03/20/08

Loc: Manila, Philippines 121*E 14*N
Re: Pentax XW versus Delos, an informal comparison new [Re: coutleef]
      #6037500 - 08/20/13 11:38 PM

Quote:


As for the t6 nagler, i never had the spacewalk feeling .. .. and using them with glasses turned them into plossls.




That explains it. The Nagler T6 was never really meant for eyeglass wearing observers where one of its most salient features, the spacewalk sensation it affords, will be lost on them and not fully appreciated because the eyeglasses get in the way of seeing the entire field. The Delos/Pentax with its more generous eye relief are better suited for eyeglass use.

Best,


Post Extras: Print Post   Remind Me!   Notify Moderator  
coutleef
Post Laureate
*****

Reged: 02/21/08

Loc: Saint-Donat, Quebec, Canada
Re: Pentax XW versus Delos, an informal comparison new [Re: ibase]
      #6037808 - 08/21/13 07:20 AM

Hernando,

I must specify that i always used the T6 without glasses and did not have the spacewalk effect. I,was impressed by how small and ligth they were and sharp but the spacewalk effect i had only wwith the T4 and T5. I always considered the T5 are the best naglers


Post Extras: Print Post   Remind Me!   Notify Moderator  
dscarpa
Post Laureate
*****

Reged: 03/15/08

Loc: San Diego Ca.
Re: Pentax XW versus Delos, an informal comparison new [Re: coutleef]
      #6038318 - 08/21/13 01:02 PM

No spacewalk with the T6s for me. On the plus side they are less seeing sensitive than the XWs and Delos when it came to seeing low contrast detail on Jupiter. For lunar it's the big boys hand down. They give a white highlands when clear and gray when there are thin clouds vs gray and a very off putting yellow with the Ts under the same conditions. David

Edited by dscarpa (08/22/13 04:01 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
kkokkolisModerator
Carpal Tunnel
*****

Reged: 09/23/09

Loc: Piraeus, Greece
Re: Pentax XW versus Delos, an informal comparison new [Re: dscarpa]
      #6038453 - 08/21/13 02:28 PM

Maybe we use the marketing invented (I think, please correct me if wrong) term spacewalk with a personal approach and mean different things. Personally I can't imagine how a 20mm eye lens resembles a spaceship's scattle or a spacesuit's visor. It's like comparing a sprat to a tuna fish. My spacewalk is possible with an XW, Delos, T4, LVW, Hyperion etc, because they have a window- like lens you don't need to apply as a contact lens. I understand that different people have different eyes and preferences. I, for example, could never stand contact lenses and never tried one, while my wife and kids used them a lot. My family might be able to experience a spacewalk feeling even with a 4mm Plossl (but that has to be tested).

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman81
Carpal Tunnel
*****

Reged: 03/06/08

Loc: Metro Detroit, MI, USA
Re: Pentax XW versus Delos, an informal comparison new [Re: kkokkolis]
      #6038568 - 08/21/13 03:27 PM

The Type 4 Naglers are the only Naglers I have tried and they are all in the 'Spacewalk' class, no doubt about it.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Pentax XW versus Delos, an informal comparison new [Re: Starman81]
      #6038599 - 08/21/13 03:42 PM

Agreed! The Ethoi are nice- VERY nice, with fantastic optics, and FoV horsepower like gangbusters... but they don't have the spacewalk *sense* the T4 Naglers do. And there's nothin' wrong with the T4 optics, either!

I like the throw-you-OUT-the-window explanation!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Pentax XW versus Delos, an informal comparison new [Re: kkokkolis]
      #6038619 - 08/21/13 03:50 PM

Quote:

Maybe we use the marketing invented (I think, please correct me if wrong) term spacewalk with a personal approach and mean different things. Personally I can't imagine how a 20mm eye lens resembles a spaceship's scattle or a spacesuit's visor. It's like comparing a sprat to a tuna fish. My spacewalk is possible with an XW, Delos, T4, LVW, Hyperion etc, because they have a window- like lens you don't need to apply as a contact lens. I understand that different people have different eyes and preferences. I, for example, could never stand contact lenses and never tried one, while my wife and kids used them a lot. My family might be able to experience a spacewalk feeling even with a 4mm Plossl (but that has to be tested).



Quite right. Even the 120 degree Explore Scientific eyepiece doesn't really resemble looking through a spacesuit helmet. It resembles, uh, looking through a really wide view eyepiece.
There is something kind of special about looking through a high power eyepiece with a really wide angle apparent field, though--when the field stop, though visible with peripheral vision, isn't noticeable with direct vision. You can really look around and see other stuff in the field up there and down there, and everything is at a relatively high magnification. When looking at a galaxy cluster, for instance, it gives more of a sensation of "space" between the objects. And it can aid identification (example: Stephan's Quintet, where 6 galaxies are readily visible when the close pair is magnified enough to see them as separates).

By the way, to see the full field of view of a 4mm Plossl requires, you know, a corneal implant. You remove the contact lens and attach the eye lens to the cornea. It's the only way to conquer that 2.8mm eye relief.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Pentax XW versus Delos, an informal comparison new [Re: Starman1]
      #6038658 - 08/21/13 04:10 PM

Yeah, a 4mm Plossl soooooo ain't hap'nin'!


Ultra & hyperwides permit levels of magnification that enable SEEING many objects, all-at-once, where a standard 50* view would require panning the entire scope around to see- at least at the same magnification. I'd much prefer simply panning my eyeball around in order to look directly at, in turn, any number of objects in such a field... while still preserving the entire picture for an indirect, simultaneous view.

They also enable higher-mag views in a non-tracking scope, where a 50* view would be a constant pain to keep the object within... or worse, find it again when it sails off the edge between peeks. This cannot be stressed enough where sketching is concerned, or when sharing the views with other folks. Try puttin' a newb at the wheel of a Dob at 500x with a 50* Plossl!... an exercise in frustration- for you BOTH! Needless, too.


Post Extras: Print Post   Remind Me!   Notify Moderator  
coutleef
Post Laureate
*****

Reged: 02/21/08

Loc: Saint-Donat, Quebec, Canada
Re: Pentax XW versus Delos, an informal comparison new [Re: Starman1]
      #6038728 - 08/21/13 04:50 PM

Quote:

Quote:



By the way, to see the full field of view of a 4mm Plossl requires, you know, a corneal implant. You remove the contact lens and attach the eye lens to the cornea. It's the only way to conquer that 2.8mm eye relief.




ouch, i will keep my delos!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman81
Carpal Tunnel
*****

Reged: 03/06/08

Loc: Metro Detroit, MI, USA
Re: Pentax XW versus Delos, an informal comparison new [Re: Mike B]
      #6038804 - 08/21/13 05:38 PM

Quote:

Agreed! The Ethoi are nice- VERY nice, with fantastic optics, and FoV horsepower like gangbusters... but they don't have the spacewalk *sense* the T4 Naglers do. And there's nothin' wrong with the T4 optics, either!

I like the throw-you-OUT-the-window explanation!




Whoa! That's not quite what I meant! The Nagler T4's are quite nice indeed but the Ethos is definitely spacewalk as well, how could it not be, unless we are defining the term differently.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Pentax XW versus Delos, an informal comparison new [Re: Starman81]
      #6039133 - 08/21/13 08:47 PM

Well, as has been stated- and correctly so- there is some margin for personal impressions on this "spacewalk" thing.

The T4's, for me, do a much better job of simply vanishing... leaving me in space. I suspect it's due to their large eyelens, plus their gracious eye-relief; and i DO wear eyeglasses.

The Ethoi, for all their field, do not "vanish"... i'm always cognizant of looking THRU an eyepiece. But that's me. YMMV. And quite possibly so if you're a bare-eyed observer.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Sarkikos
Postmaster
*****

Reged: 12/18/07

Loc: Nyctophobia, Maryland, USA
Re: Pentax XW versus Delos, an informal comparison new [Re: t.r.]
      #6039418 - 08/22/13 12:41 AM

Quote:

Quote:

So should we accept that the Delos 10 and XW 10 have essentially equal light transmission, since they both received a 6/6 on the French report? How does this square with field reports which indicate the Delos have greater light transmission? Personally, I tend to put more weight on field reports from experienced observers rather than lab tests. For instance, would the photometer be sensitive to the same range and peaks of light frequencies that a dark-adapted eye would have in actual field conditions?

Mike




That is the real point. But, there hasn't been enough reports that agree to arrive at a consensus on this. Hence, we are left only with human bias.
Myself and a friend compared the views between the 10 Delos and 10 XW in a TEC 180 FL targeted on comet Garradd and M71. It presented an opportunity to show any contrast/limiting magnitude differences at this scale. There were none. My friend liked the eyecup positioning better on the Delos. I liked the positioning better on the XW. It came down to ergonomics.




I don't think that a consensus would necessarily rule out human bias, but might merely represent that bias which is held by the majority. However, such quibbling concerns have too much of the odor of postmodernist deconstruction for my taste. If an observer gives an honest report of superior light transmission in one eyepiece over another, based on comparisons of threshold objects (defined as very faint objects barely seen in a given telescope by a given observer under given conditions), I will give them the benefit of the doubt, dependent on further observations.

I'm sure M71 is not a threshold object in a 6" telescope. I'm not so sure about comet Garradd at the time it was near M71, but it doesn't seem so very dim at least in the photo. I'm also not sure if a 6" telescope would be a large enough aperture to show light transmission differences between a Delos and an XW. Now, maybe personal preferences on the eyecup differences between two eyepieces do show the observer's bias, but a good comparo of light transmission between eyepieces ought to be more straightforward and obvious. Maybe I'm too optimistic.


Mike


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Pentax XW versus Delos, an informal comparison new [Re: Mike B]
      #6039457 - 08/22/13 01:16 AM

Quote:

They also enable higher-mag views in a non-tracking scope,





Well there's the problem.

Non-tracking is like going back to stone knives and bear skins.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Pentax XW versus Delos, an informal comparison new [Re: Jeff Morgan]
      #6039477 - 08/22/13 01:40 AM

... or maybe THERE's the solution!


Quote:

...like going back to stone knives and bear skins.




Hey, it'll git 'er done.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Pentax XW versus Delos, an informal comparison [Re: Mike B]
      #6039485 - 08/22/13 01:48 AM

Quote:

Well, as has been stated- and correctly so- there is some margin for personal impressions on this "spacewalk" thing.

The T4's, for me, do a much better job of simply vanishing... leaving me in space. I suspect it's due to their large eyelens, plus their gracious eye-relief; and i DO wear eyeglasses.

The Ethoi, for all their field, do not "vanish"... i'm always cognizant of looking THRU an eyepiece. But that's me. YMMV. And quite possibly so if you're a bare-eyed observer.





Yes, the 17T4 was a very visceral eyepiece as very few others are. At one time I said if I could only have one eyepiece, just weld the 17T4 into my focuser.

Then I tried the 13 Ethos. Optically, it was better and after careful comparison between myself and a neutral observer there was just no doubt about it. So I reluctantly sold off the 17T4 (and the 12T4).

But the 13 Ethos just wasn't an enjoyable eyepiece to use once the AFOV novelty wore off. What you said rings absolutely true. To see the field requires lots of (for lack of a better term) work. The longer the observing session is, the more you notice it.

But what to do at that point? I knew that I could not go back to the 17T4 since I had found a sharper eyepiece, any thought of doing so was merely nostalgia working against experience and better judgment.

Then Delos came along. After trying the 10 mm I knew this was the line I was waiting for. As many others have reported, I found it even better optically than Ethos. So it was merely a waiting game for the Tele Vue to release all of the focal lengths.

No, Delos is still not the visceral experience of the T4. But in the end the sharpness and contrast wins the day and I didn't have to bob my head like a pigeon to see everything. The slightly smaller size is easier on both of my scopes and greater eye relief was nice. And best yet, it did it about half the price. What's not to like?

And I still might go back for that 17T4


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | (show all)


Extra information
29 registered and 37 anonymous users are browsing this forum.

Moderator:  ausastronomer, droid, cbwerner, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 5115

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics