Televue 32mm Plossl - Dissapointed

[cloudsweeper]

17 minutes ago, jetstream said:

Sadly it seems as if I have wasted a lot of money on eyepieces when I guess theres not much difference between them. Apparently no need to keep buying new ones. Good to know.

I suspect you're not far off the mark Gerry!  But do buy more, since it's good to have a large selection so you can fine tune your observing - I couldn't manage with just three or four.  I sometimes wonder if the main criteria are such things as FOV (or lack of it) and eye relief.  

*ducks below parapet*

Doug.

[jetstream]

1 hour ago, cloudsweeper said:

I suspect you're not far off the mark Gerry!  But do buy more, since it's good to have a large selection so you can fine tune your observing - I couldn't manage with just three or four.  I sometimes wonder if the main criteria are such things as FOV (or lack of it) and eye relief.  

*ducks below parapet*

Doug.

Yes I'm feeling very very blue right now I just new I should have stuck with the 10mm MA supplied with the H130! What a blunder - I bought other eyepieces...

[Don Pensack]

2 hours ago, jetstream said:

Sadly it seems as if I have wasted a lot of money on eyepieces when I guess there's not much difference between them. Apparently no need to keep buying new ones. Good to know.

Don't be snide.

I didn't say there was NO difference.  There are HUGE differences between eyepieces in the outer field--in chromatic aberration, astigmatism, field curvature, distortion, transmission spectrum, etc.

Great seeing won't turn a poor eyepiece into a good one.

The differences on axis, though, in comparison, are small.  I've owned 345 eyepieces so far, and though a direct comparison may reveal small differences on axis, they are of a very small magnitude compared to seeing variations.

Jupiter, for example, is simply amazing in any eyepiece with Pickering 10 seeing.  And it's rubbish in Pickering 1 seeing.  The maximum axial difference I've seen (except in 3 eyepieces that were defective) is tiny in comparison to seeing.

By all means, compare, and keep what you like, but axial differences in light scatter and contrast are generally more noticeable than sharpness differences.

This is especially true given that most observers do not have perfect vision, and may even have some considerable aberrations added by the eye.

And if the eyepieces have good quality, the differences on axis are even smaller

[Don Pensack]

 

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Edited July 10, 2020 by Don Pensack

[Don Pensack]

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Edited July 10, 2020 by Don Pensack

[jetstream]

12 minutes ago, Don Pensack said:

The differences on axis, though, in comparison, are small.  I've owned 345 eyepieces so far, and though a direct comparison may reveal small differences on axis, they are of a very small magnitude compared to seeing variations.

This is fantastic news!

I only observe on axis and as such will just use the 10mm Ma and not my 10mm Delos as the on axis difference will be comparatively small.

[Don Pensack]

Sigh. 

OK, go ahead.  I have a thick skin and can take it, no matter how thick the sarcasm.

Actually, oddly enough, there are some dyed-in-the-wool planetary observers who look for the older Japanese-made Meade MA eyepieces from the '80s/'90s

because they say they are very sharp and contrasty.  Maybe so--a lot depends on the polish on the lenses and the intangible factor--the closeness of the execution to the design.

An optical designer may pen a superb eyepiece, but if the factory doesn't make it to spec, it won't perform like spec either.

Those guys would argue the Delos has too many lenses and scatters more light.   What say you? 

 

[jetstream]

Like I said- I do see on axis differences in sharpness and the Delos is right up there in this department, bested by the Zeiss zoom and Docter by a bit under the best of conditions. You were right btw- years ago a discussion led to the idea that the Zeiss zoom loses a bit of sharpness right near the high end of its range, barlowed or not- and I see this.

The Delos is the deepest widefield out there and I've been comparing the Doc to it in this regard and its very close, but the nod might be going to the Delos. I test scatter in the TSA120 and Zeiss prism diag. Televue has a very good build on all the Delos I've tried- my 17E is on the chopping block due to the super 17.3mm.

With regard to complex lens eyepieces- not only does the design matter but possibly more important is the execution of the design and the quality control so there no "good ones" but all of equal and top quality. My 7mm KK is top tier, my 5mm KK sub par...

Eventhough I don't own "top" orthos, I've sorted through a bunch to come up with good ones and use these on the faintest of galaxies and PNs with great luck. The vg 25mm TV "plossl" is my goto Horsehead eyepiece was the first to show it in my 10" dob. My pair of 32mm TV plossls are a fixture in the Binotron 27s for low power lunar viewing in the 15".

So maybe I won't use the 10mm MA after all (worst EP Ive ever had) and keep on going with the TV's, Doc/Zeiss and the superb Vixen HRs- and of course my beloved cheap orthos.