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Wider-Field, higher-power Lunar views?

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#1 cpsTN

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Posted 23 March 2013 - 03:01 AM

I was going to put this in the EP forum, but the Lunar people are mostly here. I am currently using all plossls in 1.25" format with barlows. I am looking for a couple or so EPs in the UNDER 10mm range in the FOV range of 65* and up. I am looking for a power range centered around 250x (FL of my dob is 1520mm). To give you an idea of what I am looking for, I really like the view I get from my 12.5mm plossl and shorty barlow (243x) but I want to have somethng that is not limited by 50* or so FOV of the plossls. I would like to limit the cost for each to under $100 if I can.

#2 Kutno

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Posted 23 March 2013 - 08:11 AM

Charles,

It provides something slightly under the magnification you are seeking, and will most likely somewhat exceed your budgetary limit; nevertheless, the original design version of the 7mm Nagler is my all-time favorite ocular; and that says it all.

#3 azure1961p

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Posted 23 March 2013 - 09:43 PM

Explore Scientific makes wide angle oculars that many like without the Televue price tag. Ill probably going with a couple of these in the future though for deepsky.

I'd post this in the eyepiece forum too.

Pete

#4 buddyjesus

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Posted 24 March 2013 - 02:06 AM

I thought the view was flat in my Nagler type 1. The moon looks more crisp and dimensional when I use orthos and plossls.

I happen to like barlowing my longer focal length plossls for eye relief and due to the relatively tight(compared to modern design) FOV. Better comfort and less to sketch.

Just food for thought. Can't hurt to buy one eyepiece and use that as a model for proof of concept.

#5 MikeBOKC

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Posted 24 March 2013 - 08:51 AM

Moon is pretty spectacular through my Pentax XW7.

#6 azure1961p

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Posted 24 March 2013 - 09:59 AM

PENTAX really seems to be getting the nod by alot of observers. I might opt for a pair at some point.

Pete

#7 photonovore

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Posted 24 March 2013 - 11:30 AM

Consider: http://www.owlastronomy.com/exwide.htm in 6mm, speced with a 66degree FOV. One of Owl's old models that is an old favorite of mine is a 9mm of similar design. disclaimer: I am not a believer in "get what you pay for" as necessarily axiomatic in EPs for lunar use as comparison testing in definition delivered has not sustained that concept. But, I also use tracking mounts exclusively to base this opinion upon, so edge definition is much less impt to me than center field definition. I think you will find that most of the added expense in wide field EPs is spent in increasing edge definition, so if you require that characteristic, then 'expensive' is probably the way to go...

#8 jnewton

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Posted 24 March 2013 - 12:16 PM

You could look at the Badder Hyperion line. Very nice on Luna.

#9 Tim2723

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Posted 24 March 2013 - 11:23 PM

Rather than trying for wide-field views at rather high power, have you given any thought to adding a tracking platform to your Dob?

#10 cpsTN

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Posted 29 March 2013 - 02:42 PM

I have though about tracking platforms, but then the money get in the way. I always weigh the cost vs. usability, meaning would I get enough out of it or use it enough. I had forgotten about OWL. I will look again.

#11 azure1961p

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Posted 29 March 2013 - 11:20 PM

I swear Charles, if a company like Orion finally produced a well priced EQ platform they'd sell like mad. If they could pump them out at $200 a pop - realistic- they'd sell out with a hefty waiting list.

Why they don't is beyond me. Make it altitude adjustable - maybe specify a latitude and they can have different platforms for different states or countries. Even if they were off by some - there's still a swamping difference in that over the drift method.

It'll be a banner year the day they decide to sell it.

Pete

#12 munirocks

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Posted 27 October 2013 - 01:26 PM

I'm interested to know if there might be any disadvantages that are directly due to a wide AFOV during moon viewing. For example, 1.5 years ago I had a vitreous humor detatchment in my left eye. I had lots of floaters for a while, and they are nearly all dissolved by now, but the view in that eye is ever so slightly more misty than the view in my right eye. Any extraneous light going into that eye from the top or sides tends to glare everything out, and true blacks get lightened to gray, drastically reducing contrast. I can see better when wearing a baseball cap.

Now, I reckon that an eyepiece that has a narrow AFOV is like having a baseball cap around the edges so you should get better contrast within your eyeball than when using an eyepiece with a wide AFOV, even if your eyes don't get glared out as easily as mine.

Although I love the idea of a panoramic view of the moon's surface, if you are trying to look at something specific and the field of view is big enough to show it, is changing to a wide-field eyepiece, of the same magnification, just going to reduce the contrast due to the physiology of the human eye?

#13 Astrojensen

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Posted 27 October 2013 - 03:42 PM

if you are trying to look at something specific and the field of view is big enough to show it, is changing to a wide-field eyepiece, of the same magnification, just going to reduce the contrast due to the physiology of the human eye?


That's a really difficult question to answer. I know it doesn't happen to me, but that doesn't mean someone else won't see diminished contrast when using a wide-field eyepiece.

I use a 9mm ES100 and it is sharper than my 9mm UO ortho... The contrast is fantastic and the lunar details are just etched. Simply stunning.


Clear skies!
Thomas, Denmark

#14 A6Q6

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Posted 27 October 2013 - 04:08 PM

From Thomas: "I use a 9mm ES100 and it is sharper than my 9mm UO ortho... The contrast is fantastic and the lunar details are just etched. Simply stunning." From reading your other posts I know you know what your talking about, but I don't get out to look through other peoples equipment much, so I have a hard time understanding how all those lenses in wide fields can be as sharp or sharper then your UO's

#15 star drop

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Posted 27 October 2013 - 04:21 PM

Although I love the idea of a panoramic view of the moon's surface, if you are trying to look at something specific and the field of view is big enough to show it, is changing to a wide-field eyepiece, of the same magnification, just going to reduce the contrast due to the physiology of the human eye?

You could try that test now. Just look into one of your current eyepieces at a feature that fills perhaps a quarter of the field of view. Then move your head away from the eyepiece a little so that you can no longer see the eyepiece field stop and note any change.

#16 Astrojensen

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Posted 27 October 2013 - 05:05 PM

I have a hard time understanding how all those lenses in wide fields can be as sharp or sharper then your UO's



I honestly didn't expect it either! I did expect a good view, but I was quite unprepared for just *how* good it turned out to be. And not just because of the wide field. This eyepiece is just mind-blowingly sharp. In my Zeiss Telemator, it shows clearer first diffraction rings and airy disks than my 9mm UO ortho. I have to get out my prewar 9mm Zeiss or my 0.965" 9mm multicoated Kokusai Kohki ortho to beat it. The 9mm Zeiss ortho is just a fraction of a hair sharper, the improvement over the ES is much less than the improvement of the ES over the UO! And when you don't compare them directly, the 9mm UO looks just dandy, showing a sharp and clear image. The 9mm ES100 is just better! And it is immediately apparent when inserting it into the focuser and taking a look. My 8.8mm ES82 has a sharpness on the level of the 9mm UO and I am very satisfied with it, so I wouldn't have complained at all, if the 9mm ES100 was just as sharp, but not sharper. I had not expected a clear improvement, but that is what I see.

But what is more impressive than the sharpness is the almost complete lack of glare, ghost images or reflections. An observer friend of mine remarked, after studying M13 and other things: "It's as if there's no glass inside!". OK, that was deep-sky objects, but I get the same feeling, when observing the Moon with it. It is one of the most "invisible" eyepieces I've ever seen. It is right up there with my Zeiss research-grade microscope eyepieces in image quality.

Amazingly, my 18mm ES82 has the same image quality, but the field is less immersive and there's much more lateral color near the edge. The 11mm ES82 and 8.8mm ES82 are really good, but falls a little bit short of these incredible eyepieces. Still highly recommendable, though. I've had some of my finest lunar observations ever in my Zeiss Telemator with the 11mm and 8.8mm ES82's.


Clear skies!
Thomas, Denmark

#17 A6Q6

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Posted 27 October 2013 - 05:23 PM

Thanks Thomas, I guess I'm going to have to get out to a star party and see what you all are seeing.

#18 Astrojensen

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Posted 27 October 2013 - 05:57 PM

Be forewarned that the experience can be quite intoxicating!


Clear skies!
Thomas, Denmark

#19 Rick Woods

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Posted 27 October 2013 - 07:35 PM

I've been enjoying the 100 degree ES's on the Moon lately. I wasn't going for maximum resolution (although they are very sharp!), but just being a tourist and exploring. The wide field makes up for any reduction in sharpness.

The Brandons come out for things like Mars. The Moon is so big, WF is appropriate.

#20 RobDob

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Posted 28 October 2013 - 12:16 AM

The Zhumell Z-Planetary 6mm eyepiece is a pretty good bang_for_the_buck 250x lunar eyepiece for your scope.

#21 Monoeil

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Posted 28 October 2013 - 09:43 AM

An equatorial plateform provides a comfort much superior to a WF eyepiece, there is no comparison.

If I were you, I would save and try to get one used. Honestly, it is a real added value!






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