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14mm Denkmeier

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#1 Scanning4Comets

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Posted 19 December 2012 - 08:40 PM

Heading out tonight to make a run on the 17mm Vixen LVW and my newly acquired 14mm Denkmeier !!! I borrowed the 17mm Vixen LVW off of a friend here, (JunoMike), and also just bought the 14mm Denk from him just a few hours ago. This isn't a shoot out, (it can't be because the 17mm LVW and the 14mm Denk are too far apart in FL and mag), but I wanted to check both of them out tonight !!!

I set up my telescope about an hour ago and I am still waiting for it to properly cool down. I was so excited that I couldn't wait until cool down to try out the 14mm Denk. From what I have saw, it has very nice eye relief and appears to be about 70 degrees and not the 65 advertised.

I'm just going to pop out now hoping that the skies will clear up a bit more and check these two eyepieces out! I own the 14mm Denk, so the 17mm Vixen LVW will be returned to the owner tomorrow! I think Geddy Lee will be more than happy !!! :lol: (Note the avatar pic).

I'll come back here later with pics and a short evaluation on both eyepieces !!!!

Cheers and clear skies!

#2 george golitzin

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Posted 19 December 2012 - 10:33 PM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.

#3 Scanning4Comets

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Posted 19 December 2012 - 11:38 PM

I just got in from a quick evaluation. The sky wasn't the greatest as there was a slight haze look to the sky. I really need a better night to evaluate the 14mm Denk.

From what I *did* see, the field looks more like 70 degrees as I did go back and forth between the 14mm Denk and the 10mm Pentax XW and the circle of light looked pretty close, (except for diff magnification of course). I made a verbal report talking into my digital camera while on "video mode". From my verbal report, the 14mm Denk is close to parfocal with all of my other eyepieces.

First up, after waiting for 2.5 hours for my telescope to cool down, the 14mm Denk was trained on M-42 with my Orion Ultrablock filter. The view of M-42 was scaled nicely, considering this wasn't a good night to start with because of the slight "haze" in the sky. It fits perfectly in the 14mm Denk with a bit of room to spare. I also tried the 14mm Denk alone without the Orion Ultrablock filter, but M-42 was almost washed right out. IMHO, I really need another night to test this eyepiece on deep sky, so I will pass on any more reports for deep sky for tonight.

The real treat was on Jupiter tonight. I went back and forth between the 14mm Denk + my 2" GSO ED barlow and my 7mm Pentax XW to see what the differences were. Both showed very similar magnification and the view of Jupiter between the 7mm Pentax XW and the 14mm Denk with my barlow was virtually the same. I really could see no difference, so the 14mm Denk + barlow is right up there and held it's own with my 7mm Pentax XW on Jupiter. I saw some really nice detail and a huge FESTOON on the bottom of the NEB. The detail in both eyepieces was excellent, showing hair-line detail on the face of Jupiter.

As far as sharpness on and off axis goes for the 14mm Denk, it only gets slightly soft at about the 85%-90% mark in my 10" reflector without a Paracorr, and it was not a detractor in any sense. I am talking an ever-so-slight amount of coma quite far out and at the extreme edge I could see a bit of astigmatism. On axis, the sharpness was excellent. Pretty darn good considering that the 14mm XW shows quite a bit of FC in my short FL scope, so I would rather have the 14mm Denk than the 14mm Pentax XW because of that alone, plus the throughput in these are supposed to be excellent. So far from tonight's session, I am really impressed with the 14mm Denkmeier!

I forgot to mention how comfortable this eyepiece is! I had no problem holding the eye pupil as George mentioned at all. In fact, I found that holding the eye pupil was extremely easy IMO.

I was also able to briefly evaluate the 17mm Vixen LVW and IMHO, this is another great line of the Vixen LVW's. Sharp to the edges with excellent transmission, IMHO, Vixen LVW's are real sleepers. I had the 17mm Vixen LVW on M-42 with the 2" Orion Ultrablock as well and the views were really nice.

The only reason my 10mm Pentax XW is in the picture below, is because I had Jupiter in the 10mm XW plus my barlow at around 240x, because thin cloud was covering Jupiter and 240X was perfect to use and I had some nice views with them two as well.

I really do need a better night for this evaluation, so I will leave it at that for now until next time,

Clear Skies!

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#4 george golitzin

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Posted 20 December 2012 - 03:57 PM

Well I'm glad you liked it Markus! The biggest variable in eyepiece evaluation is, I think, personal preferences--so much so, that the only way to know you're going to like an eyepiece is to try it out yourself over several nights. This seems to be your program recently! :) On which subject, what about that 13LVW you have, or had? Did you compare it to the Denk?

-geo

#5 ausastronomer

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Posted 20 December 2012 - 06:17 PM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.


Hi George,

I can only assume you got a 14mm Denkmeier that was defective in some way. Your experience is not consistent with mine in any way. I don't own the 14mm Denk but I do own the 14mm Pentax XW and the 13mm ETHOS. I have used the 14mm Denk and the 13mm Nagler T6 extensively and have used 3 different samples of the 14mm Denk.

Here is Nick Koiza's comparison of the 14mm Denk, 14mm Pentax XW, 13mm ETHOS ... My experience is 100% consistent with Nick's and I put the 14mm Denk on top of the other 3 by a small margin.

I am sure Markus will find it an outstanding eyepiece in every respect.

Cheers,

#6 junomike

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Posted 20 December 2012 - 06:26 PM

John, I'm not so sure George received a faulty D14.
Reason? I arrived at the similar results as George with the very same eyepiece I just sold Mark who finds It excellent.

I think It's more of a personal preference. Seeing that I don't own a fast Dob, I preferred the 14mm XW.

Mike

#7 ausastronomer

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Posted 20 December 2012 - 06:40 PM

Hi Mike,

Well I know personal preference comes into it a lot and some people may have issues with the comfort and ease of use factor with regard to the 14mm Denkmeier. However, I have never been able to see dimmer stars in the 13mm Nagler T6 than I can see in the 14mm Denk and that's what got me to thinking the sample may have been defective. Similarly, I have never been able to see dimmer stars in a 13mm Nagler T6 than what I can see in the 14mm Pentax XW. The 14mm Pentax XW just goes deeper each and every time for mine, compared to the 13mm Nagler T6.

I am more than happy with my 14mm Pentax XW as I don't have a problem with the FC issue with it, as its pretty flat for mine when used without a paracorr in my 10"/F5.3 newt and I use it with a paracorr in my 2 larger scopes and it delivers a beautiful flat field, when used with the paracorr. However, if I was starting out from scratch I would be giving serious consideration to going with the 14mm Denk at this focal length.

Cheers

#8 russell23

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Posted 20 December 2012 - 08:08 PM

The 14mm Denk is on my list of eyepieces that would have been perfect for me if not for one of the more significant cases of edge of field brightening when observing deep sky objects.

I think that one and the 17.5mm Nikon NAV are the two eyepieces that disappointed me the most with the EOFB issue - because other than that I thought they were outstanding - but it was too much for me to tolerate.

Dave

#9 Scanning4Comets

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Posted 20 December 2012 - 08:55 PM

Dave,

There are no EOF brightness issues with the 14mm Denk from what I have seen, and last night wasn't anywhere near optimal when I tried it in my telescope. I also looked through it at a darker sky site I frequent, but I was so preoccupied at the time that I kind of ignored it.

From what I saw last night, I'm going to be using this a lot more! It barlowed really nicely as well.

I went out for a second round last night at around 1:00 am. Before I went outside, I removed the bat wing and tried again with my glasses. Without the bat wing attached, I could see the entire FOV, (close to 70 degrees), with ease.

Ease of eye placement is an understatement when using the 14mm Denk. Blackouts only occur when I remove my glasses and I literally have to get up really close to make them happen. There is also no kidney beaning and having to chase black spots around. Again, the sky wasn't the greatest, so I am anxious to look through it in better skies and pay close attention next time around.

The view looks very close to the 14mm Pentax XW, if not better, minus the field curvature. That's pretty awesome if you ask me. I also recall going back and forth between it and some other eyepieces and stars just seemed so much brighter.

I'll report back again when I get the eyepiece out in darker skies.

Cheers,

#10 Moonglum

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Posted 20 December 2012 - 09:24 PM

About a month ago I compared my D14 to my E13 in my F8 APO on the Pleiades. A touch more nebulosity in the D14.

#11 wavelandscott

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Posted 20 December 2012 - 09:59 PM

I am a fan of the D14s...I class it in the same league as the Pentax and Televue offerings. YMMV

#12 george golitzin

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Posted 21 December 2012 - 12:34 AM

John, I'm not so sure George received a faulty D14.
Reason? I arrived at the similar results as George with the very same eyepiece I just sold Mark who finds It excellent.

I think It's more of a personal preference. Seeing that I don't own a fast Dob, I preferred the 14mm XW.

Mike


Exactly. As for me, my 14mm wanderings have come to rest on the Delos, and that's where I'll stay--a great companion to my XWs, yet with its own character, to be sure.

-geo

#13 johnnyha

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Posted 21 December 2012 - 02:31 AM

I tested the 14 Denks against the 13T6 and 13 Ethos a few years back on the Moon, and found the Denks trailed just a bit behind in resolution. I also had problems with grease leaking out from the rotating eyeguards onto the eye lens.

#14 russell23

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Posted 21 December 2012 - 08:36 AM

Dave,

There are no EOF brightness issues with the 14mm Denk from what I have seen, and last night wasn't anywhere near optimal when I tried it in my telescope. I also looked through it at a darker sky site I frequent, but I was so preoccupied at the time that I kind of ignored it.


Hi Mark,

I can think of a number of reasons why we might have different experiences with the 14mm Denk. One could involve the Moon and sky conditions in general. The Moon tends to wash out the EOFB effect because the entire field loses contrast.

Another possibility could be manufacturing variations with the 14mm Denk. I bought a new 14mm Denk and had to wait a while for them to be manufactured. I noticed that my 14mm Denk had internal scattering in daylight that concentrated light near the edge of the field. When I took it apart I found that the black annodizing was highly reflective and had not been painted with a flat black paint. Perhaps yours was painted internally with a flat black paint.

Another possibility is that there is a certain amount of scope/eyepiece interaction involved - although I've found that if I see it in one scope I'll see it in others with the same eyepiece.

Another possibility is that what I'm calling EOFB is something that is present, but you are looking for something different - possibly expecting something more dramatic than what it is.

I've in the past considered that it could be my own eyes, but I see it with some widefield eyepieces and not with others so I think that is not likely to be the reason. I also know that certain eyepiece lines such as the Baader Hyperions are well known for this effect so I think perhaps I notice it at more subtle levels than what others are bothered by. But in the case of the 14mm Denk I did not find it subtle at all.

Dave

#15 Dave Ittner

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Posted 21 December 2012 - 09:06 AM

This is the first time I have heard of anyone mentioning EOFB. As if we don't have enough minute details to take into consideration .... here comes another one.

Just how noticeable is this EOFB? Which eyepieces clearly demonstrate this?

#16 nkoiza

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Posted 21 December 2012 - 09:18 AM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.


This is really strange George as my experience was quite the opposite. I have sold my 13T6 and Ethos eyepieces and have never looked back since. I read some of your comments in past 14 Denk threads and have questioned in my mind why your experience was rather negative - my initial thought was possibly a defective eyepiece but from what I am reading this may not be the case?

Nick

#17 russell23

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Posted 21 December 2012 - 10:01 AM

This is the first time I have heard of anyone mentioning EOFB. As if we don't have enough minute details to take into consideration .... here comes another one.

Just how noticeable is this EOFB? Which eyepieces clearly demonstrate this?


Dave,

This is not a new topic on this forum. Here is a thread that discusses EOFB.

The phenomenon I'm talking about is a non-uniform blackness to the sky background across the field of an eyepiece. If you look at the darkness of the sky in the central field and compare the sky background at the edge, some widefield eyepieces will show a brightening of the background near the edge. In other words while the central field appears black the edge appears a less contrasty grayish - as if scattered light is contaminating the edge of the field. It is most detectable with dark skies when deep sky observing.

How much of this varies with the eyepiece. I've seen none of it with the 28mm ES68, 22mm Vixen LVW, 10mm Delos, and 6.7mm ES82 as examples. I saw a lot of it with the 14mm Denk, 17.5mm Nikon NAV, and 42mm GSO superview.

A lot of eyepieces have the effect at a very mild level that once you notice it is easy to spot, but not necessarily bothersome. A great example of that would be the 12mm Meade HD-60. Interestingly the 12mm Celestron X-cel LX - which is apparently the same eyepiece design, showed quite a bit more EOFB than the 12mm HD-60. I also thought the 19mm Celestron Luminos had too much of the EOFB for my tastes.

Dave

#18 Tamiji Homma

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Posted 21 December 2012 - 10:42 AM

Hi Dave,

I started wondering if brighter view toward edge has something to do with AMD (Angular Magnification Distortion)?

Eyepiece with low AMD gives you uniform magnification across the field but Nikon NAV SW (or Meopta Zoom) has higher magnification at center and lower magnification toward edge, therefore you see darker at center, brighter toward edge?

Tammy

#19 johnnyha

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Posted 21 December 2012 - 11:38 AM

That is a brilliant observation Tammy!

#20 galaxyman

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Posted 21 December 2012 - 11:48 AM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.


This is really strange George as my experience was quite the opposite. I have sold my 13T6 and Ethos eyepieces and have never looked back since. I read some of your comments in past 14 Denk threads and have questioned in my mind why your experience was rather negative - my initial thought was possibly a defective eyepiece but from what I am reading this may not be the case?

Nick


We heavily compared the 14mm Denk to other high-end eyepieces.

One was with my 8" refractor on Ngc 7331 and background galaxies.

The other two eyepieces were at this time a 14mm Radian and a 14mm Pentax XW.

The 14mm Denk compared to the 14mm Radian showed the galaxies, especially the faint background galaxies a bit easier. Overall image quality just looked better in the Denk.

The 14mm Pentax showed the galaxies well like the Denk, but the Denk's FOV is flat with no curvature, which the 14mm Pentax suffers a bit.

So here in a high quality refractor with good test subjects the 14mm Denk won.


Another test was from top of Spruce Knob, WV with a 18" Obsession.

Here the 14mm Denk and a 13mm Ethos, and using the Perseus cluster of galaxies.

This was a tough comparison. With so many galaxies in an 18" dob from one of the darkest spots in the east…well I can say a 13mm Ethos inserted in the focuser was awesome!!!

But...the fainter members visible in both eyepieces were very slightly easier in the Denk. Some of the faintest in the Ethos would go in and out visually, but the Denk could hold them more often. This was very subtle.

The 14mm Denk is more comfortable to me with the nice E.R.

If I had to choose here between these two eyepieces though, it would be the Ethos. Of course that comes at a cost, but that overall view of Ngc 1275 and it's many friends was terrific in that huge FOV.


Karl
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#21 Scanning4Comets

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Posted 21 December 2012 - 11:50 AM

We heavily compared the 14mm Denk to other high-end eyepieces.

One was with my 8" refractor on Ngc 7331 and background galaxies.

The other two eyepieces were at this time a 14mm Radian and a 14mm Pentax XW.

The 14mm Denk compared to the 14mm Radian showed the galaxies, especially the faint background galaxies a bit easier. Overall image quality just looked better in the Denk.

The 14mm Pentax showed the galaxies well like the Denk, but the Denk's FOV is flat with no curvature, which the 14mm Pentax suffers a bit.

So here in a high quality refractor with good test subjects the 14mm Denk won.


Another test was from top of Spruce Knob, WV with a 18" Obsession.

Here the 14mm Denk and a 13mm Ethos, and using the Perseus cluster of galaxies.

This was a tough comparison. With so many galaxies in an 18" dob from one of the darkest spots in the east…well I can say a 13mm Ethos inserted in the focuser was awesome!!!

But...the fainter members visible in both eyepieces were very slightly easier in the Denk. Some of the faintest in the Ethos would go in and out visually, but the Denk could hold them more often. This was very subtle.

The 14mm Denk is more comfortable to me with the nice E.R.

If I had to choose here between these two eyepieces though, it would be the Ethos. Of course that comes at a cost, but that overall view of Ngc 1275 and it's many friends was terrific in that huge FOV.


Karl
E.O.H.


:applause: :bow:

#22 george golitzin

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Posted 21 December 2012 - 03:08 PM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.


This is really strange George as my experience was quite the opposite. I have sold my 13T6 and Ethos eyepieces and have never looked back since. I read some of your comments in past 14 Denk threads and have questioned in my mind why your experience was rather negative - my initial thought was possibly a defective eyepiece but from what I am reading this may not be the case?

Nick


Well I don't know about a defective unit, as I only had a sample of one. You are not the first to suggest this, but I find it rather strange that those who like an eyepiece find it necessary to assume that those who don't like the eyepiece must have a defective unit. Again, all I can say is that very little--other than lab testing--is objective when it comes to eyepieces. It's all about the interaction between viewer and eyepiece. My observation, which you quote above, was my very subjective impression of the eyepiece on one night--but it was sufficient for me to know that I would not keep the eyepiece. Here is that journal entry in full:

First impressions of 14 Denk (in 10” f/5): the fov is identical to the 13T6, perhaps slightly larger; the fov seems much larger than 65 degrees. The field is very flat and evenly illuminated; the 13T6 seems possibly to have central darkening by comparison. However, the field is, well, lackluster. Stars do not shine as brilliantly as they do in the bracketing 13 and 16 Naglers: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. On the cluster itself, this had a noticeable effect: when viewing with the Naglers, certain stars in the periphery of the cluster shone more brightly within the halo, proclaiming themselves, so to speak, and giving the cluster a definite character; this was much more muted in the Denk, leaving the cluster lifeless, uniform, flat. A similar quality held true on M11 as well. Only M17 seemed slightly better in the Denk, because of the more even illumination around the edge of the eyepiece; this helped the nebula stand out a little better in the sky as a whole. But with an OIII, the 13T6 seemed to show more detail within the Nebula, and again, certain stars shone through the filter with jewel-like brilliance: this brilliance was washed out, missing, in the Denk. Repeatedly, I bracketed views in the Denk with the 13 and 16 Nags, thinking perhaps the 13 had an exit pupil advantage—but that same jewel quality held in the 16 as well, while absent in the Denk. I would add that while testing for stellar visibility, I was careful to keep my head covered with a dark blanket, so that the Denk was not compromised by its lack of eyeguard. The eyepiece was tested with and without a paracorr. Without the paracorr, the eyepiece nicely displayed the comatic seagulls of stars at the edge; these tightened nicely with the paracorr. However, I was at the absolute limit of travel to focus the eyepiece with the paracorr—its position is slightly inward from the XWs.

As for ergonomics, the absence of a solid (or even soft) eyeguard to position the eye makes the Denk difficult to use: it has very nice eye relief, but the winged eyeguard is insufficient to hold the eye in position. And the eyepiece is very demanding of precise position: a little off-axis, and stars splayed out in rays. No doubt this is my own astigmatism, which affects all eyepieces to some extent; but the naglers were less prone to do this.

So, I am very disappointed. The XWs were clear winners over the shorter type 6 Naglers, for my purposes. The Denk is a clear loser against the 13T6.


#23 nkoiza

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Posted 21 December 2012 - 03:18 PM

Well I hope you like the 14 Denk better than I did. I was unimpressed. Nice eye relief, except the lack of an eyecup made it very hard to hold the pupil; and bracketing it with the 13T6 and 16T5 naglers, it resolved fewer stars: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. Stars just didn't have the jewel-like brilliance in the Denk that they had in the Naglers.

Hope you fare better!

-Geo.


This is really strange George as my experience was quite the opposite. I have sold my 13T6 and Ethos eyepieces and have never looked back since. I read some of your comments in past 14 Denk threads and have questioned in my mind why your experience was rather negative - my initial thought was possibly a defective eyepiece but from what I am reading this may not be the case?

Nick


We heavily compared the 14mm Denk to other high-end eyepieces.

One was with my 8" refractor on Ngc 7331 and background galaxies.

The other two eyepieces were at this time a 14mm Radian and a 14mm Pentax XW.

The 14mm Denk compared to the 14mm Radian showed the galaxies, especially the faint background galaxies a bit easier. Overall image quality just looked better in the Denk.

The 14mm Pentax showed the galaxies well like the Denk, but the Denk's FOV is flat with no curvature, which the 14mm Pentax suffers a bit.

So here in a high quality refractor with good test subjects the 14mm Denk won.


Another test was from top of Spruce Knob, WV with a 18" Obsession.

Here the 14mm Denk and a 13mm Ethos, and using the Perseus cluster of galaxies.

This was a tough comparison. With so many galaxies in an 18" dob from one of the darkest spots in the east…well I can say a 13mm Ethos inserted in the focuser was awesome!!!

But...the fainter members visible in both eyepieces were very slightly easier in the Denk. Some of the faintest in the Ethos would go in and out visually, but the Denk could hold them more often. This was very subtle.

The 14mm Denk is more comfortable to me with the nice E.R.

If I had to choose here between these two eyepieces though, it would be the Ethos. Of course that comes at a cost, but that overall view of Ngc 1275 and it's many friends was terrific in that huge FOV.


Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.c...65?feature=mhee
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


I agree it's marginal between the Ethos and Denk (as detailed in my review) but I like the compactness of the Denk and am not fussed about the extra FOV of the Ethos. I also prefer the natural view through the Denk.

Nick

#24 galaxyman

galaxyman

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Posted 21 December 2012 - 03:46 PM

What's interesting is we have around 7 observers in the CAS that own the 14mm Denk, and nothing but stellar appeal for this eyepiece in different types and size scopes up to 25".

Nick - That is one big reason that I won't sell the 14mm Denk, particularly for the much larger price tag of the Ethos. The comfort of the Denk is a big plus.

Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.c...65?feature=mhee
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos

#25 Scanning4Comets

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Posted 21 December 2012 - 08:01 PM

Well I don't know about a defective unit, as I only had a sample of one. You are not the first to suggest this, but I find it rather strange that those who like an eyepiece find it necessary to assume that those who don't like the eyepiece must have a defective unit. Again, all I can say is that very little--other than lab testing--is objective when it comes to eyepieces. It's all about the interaction between viewer and eyepiece. My observation, which you quote above, was my very subjective impression of the eyepiece on one night--but it was sufficient for me to know that I would not keep the eyepiece. Here is that journal entry in full:

First impressions of 14 Denk (in 10” f/5): the fov is identical to the 13T6, perhaps slightly larger; the fov seems much larger than 65 degrees. The field is very flat and evenly illuminated; the 13T6 seems possibly to have central darkening by comparison. However, the field is, well, lackluster. Stars do not shine as brilliantly as they do in the bracketing 13 and 16 Naglers: examining a field next to M15, stars that were repeatedly easy in both Naglers were difficult in the Denk, and stars that were difficult but fairly steady in AV in the Naglers were nearly invisible in the Denk. On the cluster itself, this had a noticeable effect: when viewing with the Naglers, certain stars in the periphery of the cluster shone more brightly within the halo, proclaiming themselves, so to speak, and giving the cluster a definite character; this was much more muted in the Denk, leaving the cluster lifeless, uniform, flat. A similar quality held true on M11 as well. Only M17 seemed slightly better in the Denk, because of the more even illumination around the edge of the eyepiece; this helped the nebula stand out a little better in the sky as a whole. But with an OIII, the 13T6 seemed to show more detail within the Nebula, and again, certain stars shone through the filter with jewel-like brilliance: this brilliance was washed out, missing, in the Denk. Repeatedly, I bracketed views in the Denk with the 13 and 16 Nags, thinking perhaps the 13 had an exit pupil advantage—but that same jewel quality held in the 16 as well, while absent in the Denk. I would add that while testing for stellar visibility, I was careful to keep my head covered with a dark blanket, so that the Denk was not compromised by its lack of eyeguard. The eyepiece was tested with and without a paracorr. Without the paracorr, the eyepiece nicely displayed the comatic seagulls of stars at the edge; these tightened nicely with the paracorr. However, I was at the absolute limit of travel to focus the eyepiece with the paracorr—its position is slightly inward from the XWs.

As for ergonomics, the absence of a solid (or even soft) eyeguard to position the eye makes the Denk difficult to use: it has very nice eye relief, but the winged eyeguard is insufficient to hold the eye in position. And the eyepiece is very demanding of precise position: a little off-axis, and stars splayed out in rays. No doubt this is my own astigmatism, which affects all eyepieces to some extent; but the naglers were less prone to do this.

So, I am very disappointed. The XWs were clear winners over the shorter type 6 Naglers, for my purposes. The Denk is a clear loser against the 13T6.


First of all, Only one night of an observation is clearly not enough time to fully evaluate an eyepiece. You need to do it over the course of several nights with different conditions and scopes. My main instrument is a 10" F/4.7, so this is my main criteria when evaluating this eyepiece. I'll be testing it a lot more through many different scopes as well.

Second, you say that "First impressions of 14 Denk (in 10” f/5): the fov is identical to the 13T6, perhaps slightly larger;" How this is even possible is puzzling because the 13mm Nagler is an 82 degree eyepiece and the apparent FOV would leave you with a more immersive look, no?

Then you said that the 13mm Nagler had a "central darkening", but the 14mm Denk was "very flat and evenly illuminated".....Strange. Lackluster I find hard to believe because in trying mine next to my other eyepieces, I found the 14mm Denk showing excellent transmission......and that was a bad night !!!! I'll have to really put this EP thru the paces over several nights soon!

I have access to a 16mm Nagler T5, but not a 13mm Nagler T6. So when I do head out to the site I frequent, I can go back and forth between the 14mm Denk and the 16mm Nag T5 to see what the differences are over several nights to boot!

As for ergonomics, the absence of a solid (or even soft) eyeguard to position the eye makes the Denk difficult to use: it has very nice eye relief, but the winged eyeguard is insufficient to hold the eye in position. And the eyepiece is very demanding of precise position: a little off-axis, and stars splayed out in rays. No doubt this is my own astigmatism, which affects all eyepieces to some extent; but the naglers were less prone to do this.


I also found the opposite to this here. Your description was like you were using a 12mm Nagler T4. In the 14mm Denk, I had the bat wing folded in the down position and eye placement was super easy. Very demanding eye placement on the 14mm Denk is a huge overstatement.

Your report seems a bit wishy washy.

Cheers,






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