New eyepiece Docter 12.5mm

[Pondus]

I have been wanting a high quality mid power eyepiece for some time and finally decided for Docter 12.5mm.
Also shortlisted was Ethos 13mm and Nikon Nav HW 12.5mm.
Logically I should have opted for one of the 100° since I already have the ES20mm.

 

But.

 

This eyepiece has been on my mind for some years, and I simply could not resist getting one once I started looking for a decent eyepiece in the 12-14mm range.

I know the Docter 12.5mm has its fans on CN (especially for binoviewing), and I am also aware that a few members at SGL also own,

or at least have owned, this one (to my knowledge very skilled observers indeed).

 

Unfortunately I will not be able to test it out on dso`s until earliest end of August, but I hope I`ll at least will get some lunar views (at 96x) before that.

This purchase is part of building a small set of fixed  eyepieces (so far I only got this new one plus ES20mm).
For higher powers I am not yet sure what to buy, but theres no rush. From 59N, planets will be very low until Mars opposition in 2020, besides I am still gonna keep the Hyperion zoom.

 

The retailer (Okularum) also had the Omega/DGM NBP filter, so I purchased the 2". Read a very good review about this filter, and I also recall Johns post about it here at SGL :

 

https://stargazerslounge.com/topic/262679-omega-dgm-nbp-filter/

I havent paid much attention to nebulas (except the famous one), and hopefully this filter will help me find new favorite objects in the night sky.

 

A slightly overexposed image (and I`ve already been fiddling With the eyecup):

 

 

Rune

 

[Stu]

Lovely eyepiece, I'm sure you won't be disappointed  

[michael.h.f.wilkinson]

That looks great. I have considered replacing my Nagler 12mm T4 with that one. The 12T4 is the least used of my three T4s, and I feel it is not quite as good and comfortable as the 17T4 and 22T4. The Docter has a great reputation. Looking forward to a full first-light report 

[John]

The Docter eyepieces have a superb reputation

I only wish there were more in the range.

I think you will enjoy the NBP filter too. David Knisely (the filter guru) rates it very highly.

[Pondus]

Once the eyepiece arrived I wondered if I should have gone for the Ethos instead.

(says probably  more about me and my ever present second thoughts mentality about everything. Especially when pricey..)

But it certainly oozes quality. Very solid build. Nice package. No endcaps though..

 

Rune

[Highburymark]

17 minutes ago, Pondus said:

Once the eyepiece arrived I wondered if I should have gone for the Ethos instead.

(says probably  more about me and my ever present second thoughts mentality about everything. Especially when pricey..)

But it certainly oozes quality. Very solid build. Nice package. No endcaps though..

 

Rune

Congratulations. I wouldn't spend any time wondering about the Ethos unless you need the extra fov - from what I've read the Docter is about as good as it gets.

[Stu]

Have no regrets

One practical thing I like is that you can unscrew the top ring and then cleaning the exit lens becomes very easy as it is completely flush with the edge.

[Pondus]

41 minutes ago, Stu said:

Have no regrets

One practical thing I like is that you can unscrew the top ring and then cleaning the exit lens becomes very easy as it is completely flush with the edge.

Thank you for the tip.

I know you at some point had the Docter 12.5mm Stu, I did not notice if you sold it or not?

[Piero]

That is a super eyepiece combined with a super filter! Don't have any regrets! 

On your 8" dob, it will give you outstanding views!

 

I never looked thought an Ethos, but I did though Delos. These are lovely eyepieces providing high quality views. IMO, the docter is a step above on axis on solar, DSO, moon, and planets. It's also very very comfortable. 

The only criticism (this is subjective though!) I have read about the Docter compared to TV eyepieces is the presence of AMD (angular magnification distortion) visible at the edge. TV try to guarantee a level of AMD below 1%. As a consequence the level of RD (rectilinear distortion) increases proportionally. The Docter shows some AMD, but less RD than TV eyepieces, at the edge.

Now the question is... how would one be affected by this? Well, if you hate AMD, then you might not like this eyepiece. If you actually prefer some AMD in, you will like it a lot. Personally, I don't really bother about the fact that a double star is slightly tighter at the edge (=a negative effect of AMD), whereas I like seeing the Moon with an almost spherical shape at the edge (= a positive effect of AMD as a reduction in RD). 

 

The Baader VIP 2x is great tool with the Docter. You won't lose anything.

I tested the docter vs Delos 12mm + Powermate 2.5x, and I could not spot any difference instead.....

[YKSE]

Congratulations, it's a very nice eyepiece

As to RD and AMD, it's just like Piero has stated, the mixture of more AMD and RD is a very good balance, IMHO, you'll a round Sun or full Moon as a perfectly round (to my eye) disk, no matter where you place it, even near the edge and on axis at the same time, in 120ED's 1.2° TFOV.

If you have Mark III zoom, the small eye cup there suit docter perfectly (with rubber eyeguard rolled down).

Looking forward to your first light.

 

[Pondus]

Thank you @Piero and @YKSE for sharing Your knowledge. This is really helpful and informative read. I honestly dont know much about Geometrical distortions (pros, cons, what I`d prefer)

 

Rune

[Piero]

Another example is this: 

Consider in daytime a pole placed at a certain distance. The more you move the image of this pole to the edge of the field of most astronomical eyepieces (certainly TV eps), the more you will see this pole bending. This distortion is particularly noticeable in wide and ultra wide field eyepieces. Depending on the way it bends you have positive or negative rectilinear distortion. In your Docter, that pole will more or less remain straight instead. This because the Docter has presents AMD, which reduces the effect of RD. AMD and RD are inversely proportional and are distortion visible at the edge. You cannot eliminate both of them. Because of this feature, the Docter (and other eyepieces with some level of AMD) are often called daytime (or terrestrial) eyepieces, whereas eyepieces minimising AMD are called astronomical eyepieces. Seriously, this is just a name. Many eyepieces originally developed for daytime observation revealed to be great in night time. I believe the intention of reducing AMD at most is due to the fact that night time observers *enjoy* observing star clusters spanning across the field without changing in magnifications between on axis and field stop. Therefore the separation of a double star would be nearly identical if these are placed on axis or near the edge. Of course, the introduction of a large amount of RD has the consequence that large bright objects (e.g. the Moon, Jupiter, the Sun) will appear elongated as they approach the field stop. 

In the docter, these objects preserve their shapes. On the other hand, if you pay attention, you can see that a double star becomes a bit tighter as soon as this reaches the field stop. 

Anyway, AMD and RD are distortions visible at the edge of a (wide field) eyepieces. On axis, the Docter is a terrific high resolution eyepiece. Ergonomically, it's solid, has integrated 1.25" and 2" barrel which will be handy in your telescope as you won't need adapters, and the eye rubber is very comfortable. I think it is around 17-18mm eye relief. Light scattering is very very minimal too. 

[jetstream]

The Docter 12.5mm UWA is one of my very best eyepieces- I consider it a widefield ortho really. Actually some of my orthos show a marked degree of pincushion near their field stops, whereas the Docter holds neutral (almost).

The Docter gives superb on axis views with little, if any degredation across its entire FOV. You will be hard pressed to find a lower scatter eyepiece. To my eyes the Ethos don't compare to the Docter in these 2 areas (on axis sharpness, scatter).

@Pondus wait until you see M42 in this eyepiece.....