MM3/4 60. Fixed x30 eyepiece? (1 Viewer)

[yarrellii]

I've been using an Opticron MM3 60 ED travelscope for a couple of years now, and am really happy with its performance, it has absolutely fulfilled my expectations and needs. I bought it together with a SDL V2 zoom eyepiece that works nicely as well across the range (although there is the logical drop in quality beyond... say x35-40). Anyway, I've been thinking of getting a fixed eyepiece, I'm thinking about a wide angle clear piece around x30, since this is more or less where I usually spend most of my glassing hours. I've scanned Opticron website and I've found:
40831 HDF T WW which delivers x23 for the 60 mm lens
40810 HDF T WW which delivers x17 for the 60 mm lens
40931 HR2 WA which delivers x25 for the 60 mm lens

Now I'm facing a series of questions that maybe some forum users have encountered as well in the past, so any hint, answer, clue or suggestion is more than welcome

- I've read nice comments about the x23 magnification, but I'm afraid it would still be on the short side for my preferences (looking at x23 on the zoom eyepiece I can't help feeling the need for some more reach).
- The x25 of the HR eyepiece could probably be ok in terms of magnification, since x25 seems the lowest I would want to go, but I'm afraid about the image quality, since I assume the HR series is of an inferior quality than the HDF series (please do correct me if this isn't so). Would I notice a loss in quality between a fixed HR against a zoom HDF?
- Maybe there is a discontinued Opticron eyepiece in this range (x30) worth looking for on ebay?
- Wildcard: is there a x30 (maybe x28) eyepiece from another brand that could suit the MM3 60 scope? (I am aware that some Opticron eyepieces have been used on some Kowa scopes, so maybe there is a combination to be found somewhere)

(Thanks for reading this far!)

I hope I'm not the first with these ideas/needs, so your help or ideas are much appreciated!

 

[pete_gamby]

The HR won't be as comfortable to use or as sharp as a comparable HDF. However it would have a wider field of view compared to the HDF at the same magnification.

The discontinued 40858 HDF would be 32x on the MM3 60. Info is here:

https://www.opticron.co.uk/our-products/eyepieces/hdf-eyepieces/40858-hdf-t-ww-eyepiece

By some stroke of luck we have one in our ex-demo stock. It has been quite well-used at exhibitions so the eyepiece thread has lost some paint and the markings on the body are somewhat worn. There's also a 2mm round scratch on the body. Optically it is in excellent condition. Would be covered by 10 year warranty.

If you're interested to buy it please email me at [email protected] and I'll confirm price, payment method etc.

Cheers, Pete

 

[baz1973]

I have that exact eyepiece and scope combination, and I can confirm it's an absolute winner. I rarely use the zoom anymore.

 

[yarrellii]

The discontinued 40858 HDF would be 32x on the MM3 60... By some stroke of luck we have one in our ex-demo stock... If you're interested to buy it please email me...

Wow, thank you so much for the swift reply and offer, much appreciated. You got mail

 

[yarrellii]

baz1973, out of curiosity, could you elaborate a bit on the main differences you noticed "going fixed" (I'm assuming you purchased the scope with a zoom eyepice). Thanks!

 

[baz1973]

Yes, I have the hdf zoom as well. You get a much wider field of view, a brighter image, and a sharper image. It's the field of view that makes the real difference though, as soon as you look through the fixed you'll feel as though you've been missing out on half the view all this time! Don't get me wrong, the zoom is fine, but I think you'll enjoy that fixed eyepiece.

 

[yarrellii]

Thanks, baz1973, that was very informative. I've already accepted Pete's (very) tempting offer, and now am really looking forward to enjoying all those things you mentioned. I forgot to point that I live in Ibiza, where it is sunny more often than not, and I hardly do any birding in dark conditions, where I assume the x30 would struggle and surely a x18 eyepiece would be much more suitable. Anyway, really excited to give the little MM3 a boost. So far, so good.
And thanks Pete again for the impeccable response to my query

 

[Patch67]

Pete - if you happen to find another 40858 in the cupboard I'll take it!

 

[yarrellii]

Got the eyepiece today and started playing with it right away.
Pros: brighter, sharper, more contrast, less "globe effect" (see pictures), lighter
Cons: at x30 Depending on what you're looking at (especially, if it moves fast) it can be quite difficult to locate the object, so it won't be the best for hawkspotting or the like.

I've taken a few pics. Don't look at the quality, because today was cloudy and windy day, so the light conditions were different every 10 seconds or so, but the pictures (uncropped) show something special. The forum member baz1973 mentioned all the above improvements, but specially the wider FOV. Doing a completely unscientific test (seeing how many buildings I can get to see within the FOV) I haven't spotted a huge difference between both (mind you it's been impossible to do a side-by-side comparison, since I only have one scope, so all the impressions have been taken at 20 seconds intervals, the time it takes to change the eyepiece. Anyway, the feel is that you do see a lot more, it's hard to explain. The pictures show that what your eye (or the phone camera in this case) can see; your field of view when looking through the ep.: above, with SDLV2 at around x32, and below with the 40858 HDF eyepiece. After a couple of years of phonescoping with the MM3+SDLV2 I've realized that when zooming you miss (at least my phone does it) part of the FOV, hence the soft edges (tunnel effect?), while with your eye on the eyepiece you are able to enjoy the full view. This disappears as soon as you zoom to the maximum (x45) when you are able to photograph the entire FOV.
I don't know how that happens, but the image through the eyepiece is bigger and wider. If you look at the picture of the feeder (the one in the middle) you can see that the fixed eyepiece lacks the "globe effect" of the zoom ep., the background seems to wrap the feeder in a circular way.

 

[Swissboy]

………...
I've taken a few pics. Don't look at the quality, because today was cloudy and windy day, so the light conditions were different every 10 seconds or so, but the pictures (uncropped) show something special. The forum member baz1973 mentioned all the above improvements, but specially the wider FOV. Doing a completely unscientific test (seeing how many buildings I can get to see within the FOV) I haven't spotted a huge diference, but the feel is that you do see a lot more, it's hard to explain. The pictures show that what your eye (or the phone camera in this case) can fills your field of view (above, with SDLV2 at around x32, and below with the 40858 HDF eyepiece. After a couple of years of phonescoping with the MM3+SDLV2 I've realized that when zooming you miss (at least my phone does it) part of the FOV, hence the soft edges, while with your eye on the eyepiece you are able to enjoy the full view. This disappears as soon as you zoom to the maximum (x45) when you are able to photograph the entire FOV.
I don't know how that happens, but the image through the eyepiece is bigger and wider. If you look at the picture of the feeder (the one in the middle) you can see that the fixed eyepiece lacks the "globe effect" of the zoom ep., the background seems to wrap the feeder in a circular way.

Very interesting and convincing comparison! Thanks.:t:

 

[giosblue]

Would the 40858 eyepiece be a 10mm in Astro terms?

 

[yarrellii]

giosblue I have no idea about astronomy eyepieces, I always read the comments about interchangeability of astro eyepieces and feel intrigued.

 

[yarrellii]

More on the optical performance of the HDF 40858 eyepiece.
Phonescoping is far from an ideal comparison means, given the many things that can alter the outcome (the exact positioning of the phone and the eyepiece, to begin with), but can give interesting hints. Below are two images of the Moon, both taken with identical parameters (f 1,8, 4 mm, 1/125 s , ISO 100). Above is the one with SDLV2 at around x32 and below the fixed 40858 (which gives an approximate x32). The images have been cropped but not edited (no correction of levels, contrast, etc.).

The picture taken with the fixed eyepiece is a bit bigger (don't know if it's just that the eyepiece goes a bit further than x32) and shows a brighter image (especially noticeable on the Moon surface, both on the lower area and also across the transition area between light and shade you can see more craters, and the craters are a bight more detailed). However, after taking pictures of the Moon for a series of days, I've realized that the fixed eyepiece shows more CA on the edges of the image of the Moon (reddish on the lower edge, blue on the right-upper edge). The image taken with the zoom SDLV2 shows less CA on the edges; but if you take the zoom up to x45, CA is more pronounced than with the fixed HDF (it is actually very noticeable).

Going back to birds, phonescoping with the fixed x32 is not as daunting as I thought it might be (given that you cannot locate your bird at x15 and then zoom in), I seem to be able to put the object in frame faster than I anticipated.

A collared dove and a house sparrow, both pictures are cropped and edited, they were taken at around 20-25 m (60-75 feet). Looking through the eyepiece with your eye the images are crisp, I'd say a bit crispier and brighter than with the zoom eyepiece. It is difficult to convey that on a picture, but the results I'm getting are satisfying.

So far, very happy with the eyepiece. A nice addition to a nice scope.

 

[pete_gamby]

Would the 40858 eyepiece be a 10mm in Astro terms?

It's a 12mm focal length.

HTH

Cheers, Pete