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High-power eyepiece choice for my f/5.

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#1 mac57

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Posted 10 April 2013 - 06:01 PM

I want a higher-power EP, and am wondering if the ES 82 in a high power is worth the cost difference versus an AstroTech Paradigm? Are the 82's really that good for the money? I just don't want to buy the same size EP twice. All opinions welcome, and thanks.

#2 Achernar

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Posted 10 April 2013 - 06:26 PM

I would say yes, they are that good. When the seeing is good, I use my 6.7 and 4.7mm ES 82 degree eyepieces on Jupiter and Saturn often, even though on the 15-inch they yield 300 and 425X. They come close to Naglers in performance, for a lot less money. The huge apparent field of view makes tracking objects through my Dobs at high power a lot easier, and that also makes looking for small and dim DSO's easier too. The only drawback they have is the eye relief is too short to see the whole FOV with eyeglasses on. Even through I wear glasses, I find the views to be more than pleasing without them, even through the 24mm I have.

Taras

#3 mac57

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Posted 10 April 2013 - 06:54 PM

Thanks, and either EP has better eye relief than what I have now.

#4 buddyjesus

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Posted 10 April 2013 - 07:24 PM

paradigm only goes down to 8mm and I read that the 8mm is the worst of the bunch IRT aberrations. I have not used this eyepiece but love my 12mm paradigm.

#5 planet earth

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Posted 11 April 2013 - 03:11 AM

paradigm only goes down to 8mm


They make a 5mm Paradigm, I believe your thinking about the Astro Tech flat field that goes down to 8mm. :)
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#6 Sarkikos

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Posted 11 April 2013 - 06:09 AM

buddyjesus,

paradigm only goes down to 8mm and I read that the 8mm is the worst of the bunch IRT aberrations. I have not used this eyepiece but love my 12mm paradigm.


I have bino pairs of the 8 and 12 Paradigm. They are great for bright planets and the Moon. Carlos Hernandez - an excellent observer who posts here on CN - gave them good marks.

Paradigm Dual ED

Mike

#7 tezster

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Posted 11 April 2013 - 06:46 AM

With a ~750mm focal length, I would be looking for an EP in the 3.5mm to 5mm range to give you the high power you're looking for. Anything longer than that, then I would consider getting a barlow as well.

#8 BDS316

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Posted 11 April 2013 - 08:54 AM

I read that the 8mm is the worst of the bunch IRT aberrations. I have not used this eyepiece but love my 12mm paradigm.


I'm surprised to hear this because of the CN review of the 8mm Paradigm vs the 8.5mm Pentax XF, which I consider a darn good eyepiece.

This either means that the 8mm is the dog of the line or that the others are simply amazing?

Where did you read this?

#9 Sarkikos

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Posted 11 April 2013 - 08:54 AM

The Paradigm 8mm is not the dog of the line, by any means.

Mike

#10 BDS316

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Posted 11 April 2013 - 09:09 AM

The Paradigm 8mm is not the dog of the line, by any means.

Mike


That's what I would have thought before reading the above post by buddyJ. I would like to know what he read and is basing his opinion.

I was considering the purchase of the 8mm Paradigm at NEAF, in order to compare it to my Pentax 8.5mm XF, with the loser being sold in CN Classifieds.

#11 buddyjesus

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Posted 11 April 2013 - 01:25 PM

good to hear the response on the 8mm. I will look into them further then!

#12 Widespread

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Posted 11 April 2013 - 01:56 PM

Mac,

I love my ES eyepieces, but I think I read that they are corrected only to f/6. This is one of the reasons I chose an f/7 apo.

TVs are supposedly corrected to f/4. I personally don't know any other brand that claims to be corrected to f/5 or lower.

That said, the ES 82s should perform much better than your Plossls in an f/5, and of course the wide view is nice in a Dob. Moreover, they really do represent a lot of value for the price. (I would not be inclined to buy Naglers or Ethos for a Starblast.)

I don't have a Newt, but use my 6.7mm and 8.8mm ES82s a lot in my refractors, and the 8.8mm occasionally sees light in my 8SE.

Best,
David

#13 Sarkikos

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Posted 11 April 2013 - 02:09 PM

Of course, the ES eyepieces will appear better corrected at f/5 in a Newt when used with a Paracorr. The coma from the primary mirror will be reduced and the field flattened somewhat. My ES 82 30mm is excellent in my 10" f/4.8 Dob with a Paracorr. Without Paracorr not so much, but that is not the eyepiece's fault.

I had a pair of ES 82 14mm for binoviewing, but they exhibited too much field curvature for my eyes. I eventually sold both of them. I don't recall now if I ever tried one with my Paracorr to see if the field was flattened appreciably. But I bought the ES 82 14's for binoviewing planet / Moon, not monoviewing DSO, so I got rid of them.

I have an ES 82 4.7mm that is decent for planets and DSO, even without a Paracorr. I'm only selling it now because it's redundant since I recently bought an XW 5mm.

Mike

#14 BDS316

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Posted 11 April 2013 - 02:18 PM

I read that the 8mm is the worst of the bunch IRT aberrations.


Where did you read this?

#15 buddyjesus

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Posted 11 April 2013 - 03:19 PM

the carlos hernandez review stated there is off axis astigmastism that was less severe than some other eyepieces. also read a few reviews on stargazerslounge.com where they are known as BST explorers.

for the record, I have viewed through the 12mm and feel it is a winner.

#16 jrbarnett

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Posted 11 April 2013 - 05:13 PM

Do you have a Barlow? There are a few advantages of Barlowing to get higher magnification. First, a Barlow tends to correct for off-axis astigmatism that a simple, affordable longer focal length eyepiece will tend to generate at a relatively fast f/5. Second, quality Barlows can be had inexpensively. Finally, a Barlow can be used with multiple eyepieces, effectively increasing the number of unique focal lengths available to you.

I'd Barlow before I would invest in either an ES 82 or Paradigm if I was at all concerned about budget.

Regards,

Jim

#17 GeneT

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Posted 11 April 2013 - 05:21 PM

For high power--I am pleased with Delos 8, Pentax 7 XW,
Delos 6, Pentax 5 XW, Pentax 5 XO and Radian 4mm.

#18 Sean Puett

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Posted 12 April 2013 - 04:28 PM

ES82s are corrected to f4. The old explore scientific 70* were pretty good to f6 but quickly deteriorated under f6. This statement does not include the newer 68* eyepieces.
ES82s are great in fast scopes. In a newt, you will still see some coma without a paracorr or some similar device.

#19 hottr6

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Posted 13 April 2013 - 09:04 AM

Hey Jim, you can add that barlows retain the eye relief of the eyepiece being barlowed, which may be easier to use than hi-po eyepieces.

Personally, I avoid barlows. To me, they throw the OTA balance off (by a lot, especially on GEMs), are another place to introduce mechanical off-axis errors, and look like something Rube Goldberg would invent.
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#20 cpsTN

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Posted 13 April 2013 - 09:37 AM

Hey Shane! Did you know there is a gray newt attached to the end of your EP? What is the other scope - AR5,6?

#21 CollinofAlabama

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Posted 13 April 2013 - 01:47 PM

Mark,

You're in a kind of strange situation. First, I'd have to say that, although I agree with all GeneT's suggestions in terms of quality, I think they're somewhat absurd for you. All of them, except the XO, are HUGE, and compared to what is right now your heaviest eyepiece, the 25mm Sirius Plossl, monsters. They all weigh well north of 13 oz, and are something like four times heavier than your 25mm plossl. The XO, tho small like your 10mm plossl, cost almost as much as your telescope! Given the eyepieces you're comparing in your original post, I'd have to say you're in the sub $150 market, maybe the sub $100 market. GeneT's suggestions are, therefore, mostly too heavy and all irrelevant due to cost if my assumptions are correct.

Normally, I'm inclined to agree with Jim Barnett's suggestion of a good barlow. This has worked GREAT for me, btw. But Shane's parodizing picture from a scope very similar to yours demonstrates that, in your case in particular with the Orion StarBlast 6, maybe this is not the best path, either, due to the bizarre balance points created by a good barlow in your scope type. This wouldn't be an issue if the original manufacturer (probably Synta) had made the tube an inch longer, but they didn't, trying to jam as much optics into the shortest tube possible, with the inevitable result of pushing the normal focal plane out into the 1.25" focuser area. One can lament the design all one wants, but like Shane points out, that's the design you have.

Under the circumstances, I'm inclined to agree, rather reluctantly, with your original supposition of the Paradigm 5mm. I say rather reluctantly, because I've never looked through one, and I'm a little hesitant to recommend something I've never seen myself.

There is the possibility of getting a good shorty barlow type, and then Jim's suggestion might work. I'm not a big fan of the shorty style barlows, personally, but the old UO 2.8x Klee gets generally high marks on CN. Had one myself long ago before I bought my wonderful old school Orion Fully Baffled model. Another possibility is the new barlow from Baader that is being sold with their new ortho line. These might be okay. I'm not a big fan of shorty's due to the vignetting of field that they often inflict on an eyepiece. On top of that, it's almost always better, in optics, to give an optical device more room to work. Shorty's, by definition, do not, so glare, optical imperfections, etc, are all maximized with the shorty barlow design. For these reasons, I'm not such a fan, but in your scope's case, it may be the only way to go.

As for regular eyepieces to barlow, well, you have a 10mm Sirius Plossl. An okay start. I've always been a fan of the TV Plossls, and those can be had used for around $60-$80. The 11mm barlowed would be a powerful, and very sharp, planetary combination. I have no hesitation recommending it for resolution. But one must also consider eye relief. Although a barlow will enhance the eye relief, trust me, the ER on the 11mm TV Plossl is truly horrible. I'm certain the ES 4.7 and AT Paradigm 5mm would both have much better ER than a barlowed TV 11mm Plossl. There are rumors that the UO HDs are coming back, and the 12mm model would make a great size to barlow. Another possibility is the new Baader Classic Ortho 10mm. Although it's likely to be a better eyepiece than your Sirius Plossl, it is the same focal length and getting something a little different is a good idea. This guy here, from our sponsor, is a really good choice, too. This is the same Long Perng eyepiece known as the Sterling Plossl. Not expensive at all, really good FOV for a plossl, and it should yield a nice magnification barlowed.

A very good mid-range focal length eyepiece can really perform barlowed. Read this for an example. I'm not such a fan of the JOC eyepieces (ES/older Meade 5k UWA) for planetary anymore after that, and Naglers and Brandons are in the same price category of the XO, XW, Delos -- a LOT more money than you appear to be in the market for. I just don't know if a Paradigm 5mm would keep up with your Sirius Plossl 10mm barlowed, and especially a BCO 10mm ortho, TV 11mm Plossl, or similar good quality low-glass mid-range eyepiece.

Good luck

#22 Achernar

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Posted 13 April 2013 - 08:35 PM

They are most definitely corrected to F/4, if not I would see unmistakable evidence of that because a Paracorr will not remove any aberrations that originate in the eyepiece itself. They work very well at F/4.5 with or with a coma corrector, but the view is better with one than without.

Taras

#23 Astrodj

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Posted 14 April 2013 - 01:15 AM

Hi Mac,

I would recommend visiting Don Pensack's web page. Click on "Informational Articles". If you are inclined to email him with a question, I would wager you would get a very comprehensive response. He has a lot of useful information regarding barlows, eyepiece designs, and performance expectations.

He also sells many of the eyepieces recommended in this thread. IMO, you can learn much of what you want to know on his site. He is an extremely knowledgeable CN'er, especially where eyepieces are concerned. Check out his site. :jump:

#24 hottr6

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Posted 14 April 2013 - 02:22 PM

:lol: Yeah, it does look odd.

Other 'scope is not nearly as interesting as a AR5/6. It is a heavily modified #395 90mm f/11. I'm trying to find a 4"-4.5" Newt that provides better views.

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#25 izar187

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Posted 15 April 2013 - 09:19 AM

Mark,

You're in a kind of strange situation. First, I'd have to say that, although I agree with all GeneT's suggestions in terms of quality, I think they're somewhat absurd for you. All of them, except the XO, are HUGE, and compared to what is right now your heaviest eyepiece, the 25mm Sirius Plossl, monsters. They all weigh well north of 13 oz, and are something like four times heavier than your 25mm plossl. The XO, tho small like your 10mm plossl, cost almost as much as your telescope! Given the eyepieces you're comparing in your original post, I'd have to say you're in the sub $150 market, maybe the sub $100 market. GeneT's suggestions are, therefore, mostly too heavy and all irrelevant due to cost if my assumptions are correct.

Normally, I'm inclined to agree with Jim Barnett's suggestion of a good barlow. This has worked GREAT for me, btw. But Shane's parodizing picture from a scope very similar to yours demonstrates that, in your case in particular with the Orion StarBlast 6, maybe this is not the best path, either, due to the bizarre balance points created by a good barlow in your scope type. This wouldn't be an issue if the original manufacturer (probably Synta) had made the tube an inch longer, but they didn't, trying to jam as much optics into the shortest tube possible, with the inevitable result of pushing the normal focal plane out into the 1.25" focuser area. One can lament the design all one wants, but like Shane points out, that's the design you have.

Under the circumstances, I'm inclined to agree, rather reluctantly, with your original supposition of the Paradigm 5mm. I say rather reluctantly, because I've never looked through one, and I'm a little hesitant to recommend something I've never seen myself.

There is the possibility of getting a good shorty barlow type, and then Jim's suggestion might work. I'm not a big fan of the shorty style barlows, personally, but the old UO 2.8x Klee gets generally high marks on CN. Had one myself long ago before I bought my wonderful old school Orion Fully Baffled model. Another possibility is the new barlow from Baader that is being sold with their new ortho line. These might be okay. I'm not a big fan of shorty's due to the vignetting of field that they often inflict on an eyepiece. On top of that, it's almost always better, in optics, to give an optical device more room to work. Shorty's, by definition, do not, so glare, optical imperfections, etc, are all maximized with the shorty barlow design. For these reasons, I'm not such a fan, but in your scope's case, it may be the only way to go.

As for regular eyepieces to barlow, well, you have a 10mm Sirius Plossl. An okay start. I've always been a fan of the TV Plossls, and those can be had used for around $60-$80. The 11mm barlowed would be a powerful, and very sharp, planetary combination. I have no hesitation recommending it for resolution. But one must also consider eye relief. Although a barlow will enhance the eye relief, trust me, the ER on the 11mm TV Plossl is truly horrible. I'm certain the ES 4.7 and AT Paradigm 5mm would both have much better ER than a barlowed TV 11mm Plossl. There are rumors that the UO HDs are coming back, and the 12mm model would make a great size to barlow. Another possibility is the new Baader Classic Ortho 10mm. Although it's likely to be a better eyepiece than your Sirius Plossl, it is the same focal length and getting something a little different is a good idea. This guy here, from our sponsor, is a really good choice, too. This is the same Long Perng eyepiece known as the Sterling Plossl. Not expensive at all, really good FOV for a plossl, and it should yield a nice magnification barlowed.

A very good mid-range focal length eyepiece can really perform barlowed. Read this for an example. I'm not such a fan of the JOC eyepieces (ES/older Meade 5k UWA) for planetary anymore after that, and Naglers and Brandons are in the same price category of the XO, XW, Delos -- a LOT more money than you appear to be in the market for. I just don't know if a Paradigm 5mm would keep up with your Sirius Plossl 10mm barlowed, and especially a BCO 10mm ortho, TV 11mm Plossl, or similar good quality low-glass mid-range eyepiece.

Good luck



In my short fast newts, including a Synta 6" f/5, my preference is for my Siebert Star Splitters(SS3's) for higher power.
Specifically over barlowing my plossl's, ortho's, or RKE's.






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