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Best high power eyepiece for C102GT?

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#1 pugliano

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Posted 13 October 2013 - 11:16 PM

I just ordered an Agena 2" 38mm SWA eyepiece for my wide angle viewing and for large objects (ie. pleiades), for my C102GT, and now I'm looking for another good but-not-too-expensive high power eyepiece for viewing planets and double stars.

Any recommendations? I'm guessing a 1.25 inch will be better than a 2 inch for high power viewing. Is 10mm enough, or should I go even higher power? Or a 10mm with a barlow?

#2 Gary Riley

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Posted 13 October 2013 - 11:50 PM

A 10mm with a Barlow is one option or you might consider something in the 6-8 mm range as well. I have the 102mm f/9.8 Omni XLT that I have used a 5mm Hyperion with mine a few times but will generally drop back to 6 or an 8mm for sharper views on viewing the planets. A 5mm can come in handy for helping to split close doubles from time to time as well.

#3 JonNPR

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Posted 13 October 2013 - 11:58 PM

If you need to maintain longer eye relief, there are 1.25" Baader Hyperions in 8 and iirc 5mm, with 20mm ER and 68* AFOV. They slide into 2" diagonals and don't require a 1.25" adapter; that's a minor but useful time saver in the dark.

The ES 82* 1.25" series are very nice EPs at modest prices. Tighter eye relief though; about 15mm possibly a little tighter.

That Agena 38 is pretty sweet in the 102GT!

Jon



Jon

#4 CollinofAlabama

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Posted 14 October 2013 - 12:29 AM

I recommend the Baader Classic Ortho 10mm, AstroTech 12.5mm High Grade Plossl from our sponsor Astronomics (same as Sterling Plossl), and the Baader 2.25x Q Barlow. These three will give you up to five effective options. First, and obviously, are the medium powered 12.5mm and 10mm eyepieces sans Barlow. Sometimes 100x is as high as you can go. The bottom of the Q Barlow can screw off and, when attached to the bottom of the 10mm BCO, act as a 1.3x Barlow, for an effective 7.7mm eyepiece. Of course, the Barlow can also serve as a 2.25x Barlow to produce effective 5.6mm and 4.44mm eyepieces with the 12.5 Plossl and 10mm BCO (as a complete unit, with the bottom attached to the rest of the Barlow). These three wouldn't break the bank (all for around $200), and would cover a LOT of magnification bases from extreme high power, very high power, high power, high-moderate power, and moderate power. The views are top-notch (you'd have to go Nagler or Pentax to get as good a widefield view), and you will never spend $200 and get 5 ep powers in any competitive-view widefield set.

I recommend Eyepieces, Etc. or Agena for the Baader products. And you can buy them over a couple of months, picking up the 12.5mm one month, and the Baader ep & Barlow the next, to make the financial bite more manageable.

#5 t.r.

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Posted 14 October 2013 - 05:49 AM

A 10mm with a Barlow is one option or you might consider something in the 6-8 mm range as well. I have the 102mm f/9.8 Omni XLT that I have used a 5mm Hyperion with mine a few times but will generally drop back to 6 or an 8mm for sharper views on viewing the planets. A 5mm can come in handy for helping to split close doubles from time to time as well.

This pretty much nails it. I have a TV3-6 zoom for the best nights, but on average nights most of the time, 7mm to 8mm provides a sharper with more contrast view. In good seeing the scope will run with 3mm on Saturn at least, its just that the seeing has to cooperate and it won't be used as much as a 8-7mm.

#6 pugliano

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Posted 14 October 2013 - 09:36 AM

Thanks! I'm considering these three:

http://agenaastro.co...-8mm.html#pr...

http://agenaastro.co...mm-2954110.html

http://agenaastro.co...ml#product_t...

#7 PeterR280

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Posted 14 October 2013 - 09:53 AM

I like the ES 82 degree 6.7mm. The 4.7mm works too but not as sharp.

#8 Widespread

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Posted 14 October 2013 - 10:44 AM

I like the ES 82 degree 6.7mm. The 4.7mm works too but not as sharp.


+1 on the 6.7ES82

#9 Jarrod

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Posted 14 October 2013 - 11:05 AM

I was looking at the moon through my 102GT on Saturday. I highly recommend getting the 6.7mm ES82 for this scope. SPECTACULAR view of the moon with an amazing level of detail. Seeing was above average that night so I also had the 4.7 out. It was also good, but the 6.7 stole the show.

Edit: Just so you know, I wrote that *before* I saw the other recommendations for the same EP above mine.

#10 pugliano

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Posted 14 October 2013 - 11:19 AM

Thanks again! So how is the 6.7mm different than the 8.8mm? They're the same price (unfortunately both out of stock!) Should I go with the 8.8 and a barlows, or the 6.7 by itself?

#11 JonNPR

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Posted 14 October 2013 - 11:32 AM

Barlowing an 8.xmm puts you in 4.x mm territory. Normally, that would require very good and for many people, rare good seeing.

The 6.7 I would think would get more use - more nights when seeing would not limit the useful magnification,cas well as higher power than the 8.x EP.

However, if you are thinking you want a Barlow for the future, to use with other 1.25" eyepieces you might buy in the future, that's different. Personally, I would save that expenditure for later, when you would need the Barlow. The ES 6.7mm gets awfully good reviews.

Good luck!

Jon

#12 Jarrod

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Posted 14 October 2013 - 02:26 PM

The 6.7 is my most used eyepiece in my two main scopes (1000 and 1200mm focal length). In these scopes, to me, it's at a sweet spot for magnification (150-180x) where you can pull out good detail even when seeing is average. The 8.8 isn't high enough magnification for good planetary detail (for my tastes). Barlowed at 4.4 is awefully optimistic. Most nights my 4.7 shows less planetary detail because of seeing, and it's too dark (small exit pupil) for nice views of all but the brightest DSOs. I rarely feel that way with the 6.7. So I only use the 8.8 for viewing DSOs, and use the 4.7 only for planets (and then only with excellent seeing). The 6.7 is good for both planets and DSO, and I don't find this magnification to be ultra-sensitive to seeing conditions. HTH.

#13 REC

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Posted 14 October 2013 - 02:38 PM

+2 on the ES 6.7!

#14 CollinofAlabama

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Posted 14 October 2013 - 03:37 PM

-1 for JOC

See here.

I don't think they're worthless, or anything, only saying my old Meade 5000 6.7mm (read -- same OEM as the ES 6.7mm) couldn't hold a candle to the Nagler 7mm T6, and especially the Barlowed 12mm Brandon. If you want the best view and can't afford the higher end vista Nagler, Pentax, Delos options, get a good Plossl or Ortho. The 6mm BCO would be a great choice, but the eye relief may be too tight for you. A Barlowed AstroTech/Sterling Plossl or BCO will produce a better planetary image. The ES' for planetary are okay, but when you want the best, either suck it up and pay for the widefield view, or settle for a little less real estate, and get a low glass count gem, and the options I'm proposing happen to be low cost, too. The Baader 2.25x Q Barlow & 17mm AstroTech High Grade/Sterling Plossl combo will provide a 56* AFOV (not 82*, but not bad, either) and an effective 7.56x power eyepiece (besides the nice medium powered 17mm eyepiece view in its own right).

This is the better path, if the Nagler T6 or Pentax XW 7mm options are too much for you.

#15 rguasto

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Posted 14 October 2013 - 06:08 PM

I find that sterlings/high grade plossls are terrible for planets. The distortion (elongation of the disc) in the last 25% of the fov is really distracting. I find that the astro tech value line plossls (GSO) are way better for planetary use IMHO. My BCO 18mm and ultima barlow do produce a very nice image with comfortable eye relief.
-Rob

#16 CollinofAlabama

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Posted 14 October 2013 - 07:18 PM

That's an interesting post, and demonstrates the varied experiences of different people regarding eyepieces. I will simply conclude with shameless name dropping and point out that noted eyepiece reviewer-connoisseur Bill Paolini sold his TV Plossls after comparing them extensively with the Sterlings. I agree the outer part of the field, that part beyond the standard 50* AFOV, is a bit more distorted than the outer portions of a TeleVue Plossl, but considering that the TeleVues end at 50*, whereas the Sterlings continue on another 6* or so, I feel the softness is forgivable. Besides, the best place to look at planetary targets in ANY eyepiece is in the center. It's here where Mr. Paolini preferred the cooler tones of the Sterlings to the warmer TV's. For the record, Bill and I see things very differently regarding widefields, and my own jury's still out about the TV vs Sterlings Plossls, but without a doubt the Long Perng's (OEM) are worthy TeleVue competitors. Besides, when Barlowed, the edge fuzziness declines considerably tho remains an expansive 56*, whereas when Barlowed, the already somewhat limited 50* AFOV of the TeleVues reduces even further to 45*? 42*?

Despite our differences between the Long Perng Plossls, Rob, we clearly do agree that the Baader Classic Orthos are very good choices -- something Bill Paolini agrees with as well. But I will concede that, en el mundo de eyepieces, folks, YMMV.

#17 Sarkikos

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Posted 15 October 2013 - 07:04 AM

IIRC, Bill prefers the Sterling Plossl 12.5-25mm over the TV Plossls because of their wider field. He says the Sterlings below 12.5mm are not as sharp - even on-axis - as the TV Plossls. I believe that he is one of the group of observers - myself included - who do see differences among eyepieces on-axis. From what I read, we're probably a minority.

I've found that the Sterling Plossls have excellent light transmission, better than XW, Brandon, BGO and UO Ortho. I'm not sure how they compare with the TV Plossls in that regard. I keep Sterling 12.5, 17, 20 and 25mm in my deep sky case, but no TV Plossls.

I've removed all the TV Plossls from that case because I do not like warm eyepieces for DSO. But I do like them for Jupiter and lunar maria. (I prefer neutral-to-cool tone eyepieces for observing the lunar terminator.) I keep binoviewer pairs of TV Plossls from 7.4 to 26mm.

Mike

#18 BillP

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Posted 15 October 2013 - 08:34 AM

IIRC, Bill prefers the Sterling Plossl 12.5-25mm over the TV Plossls because of their wider field. He says the Sterlings below 12.5mm are not as sharp - even on-axis - as the TV Plossls.


I find the 6mm and 4mm Sterlings no where near as sharp as the rest of the line. I also see more scatter in them. All the TV Plossls are very sharp. We all have different eyes and different equipment...FWIW I find it easy to tease out on-axis differences between eyepieces, especially with the APO...you just have to know where to look on a target and for what features that are most susceptible to minor performance differences on-axis.

What I find as disadvantages with the TVs over the Sterlings in 11mm and shorter is their smaller AFOV, their warmer tone, and their need for an amplifier instead of a Barlow to not vignette. Yes, the star points will not be perfect at the larger off-axis and the 25mm has a good amount of distortion right near the field stop when planets are there, but I don't view planets at the field stop so never a problem. And since I like to Barlow that extra wide AFOV gets nice and sharp which is super nice.

It's all a balance of things and one attribute for me never trumps others. So for the overall gestalt I feel the Sterlings do a better job overall than the TVs. They also have killer good transmission and wonderfully uniform backgrounds with no lightening near the field stop. I usually keep the 25mm, 17mm, and 12.5mm in the Baader Turret on my TSA-102. Those three and a 7mm Pentax SMC Ortho or a 6mm ZAO-II in the 4th slot makes a great workhorse turret, and nice in that the wider AFOV of the Sterlings make them feel like mini-wide fields :grin: Just love their convenience. Also, they are killer sharp with that Baader 2.2x Barlow that is part of the BCO set. Was out this morning with that arrangement on my TSA observing Orion and the Perseus Double and Jupiter, and the Moon last evening - Nirvana :grin: :grin:

#19 PeterR280

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Posted 15 October 2013 - 08:56 AM

I am planning on comparing the ES 6.7mm to a good quality 7mm orthoscopic.

#20 CollinofAlabama

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Posted 15 October 2013 - 10:21 AM

My money's on the Ortho, Barlowed Ortho, Barlowed AstroTech HG/Sterling Plossl, Nagler, Pentax or Delos.

However, one thing the OP mentioned, and since we have Bill's ear, perhaps he can chime in. I've not done a lot of testing of the ES 8.8 82*. I recall Bill liking this particular model in the series best. Perhaps this one would be in the BCO/Sterling/TV Plossl class? I feel confident from my own experiences referenced above the 6.7mm is not, but since I haven't had a lot of experiences with the 8.8, and Bill has rated it best of the series, perhaps it bears consideration?

If I could coax a response on this, Bill, it looks relevant to the OP's inquiry.

#21 Sarkikos

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Posted 15 October 2013 - 10:36 AM

FWIW I find it easy to tease out on-axis differences between eyepieces, especially with the APO...you just have to know where to look on a target and for what features that are most susceptible to minor performance differences on-axis.


It does help to know the target and to have a very good idea what to look for. When I read a comparo between eyepieces with a planet or the Moon as subject, I want to hear specifics about surface features. Ideally, the observer should have years of experience in teasing out fine details. No astronomical tourists need apply. :grin:

I don't want to hear anything like, "The image was essentially the same," "No appreciable differences, "Any differences were too subtle to be concerned about." Everytime I read comments like those, I can't help but think, "Does this observer even know what to look for?" Please, give details about how fine surface features appear differently in the two eyepieces, even if those differences are only "subtle." IME & IMO, subtle differences are what it's all about for planet/lunar observation. That's what separates the XO's from the BGO's. :shrug:

Mike

#22 Sarkikos

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Posted 15 October 2013 - 10:46 AM

It's all a balance of things and one attribute for me never trumps others. So for the overall gestalt I feel the Sterlings do a better job overall than the TVs. They also have killer good transmission and wonderfully uniform backgrounds with no lightening near the field stop.


Have you ever done a direct comparion between Sterling Plossls and TV Plossls for light transmission? I suspect the Sterlings might have a little better throughput because of the neutral tone vs the warm tone of the TV's. I regret having sold both my TV Plossl 25's before I could compare them to my Sterling 25 on the Horsehead.

I usually keep the 25mm, 17mm, and 12.5mm in the Baader Turret on my TSA-102. Those three and a 7mm Pentax SMC Ortho or a 6mm ZAO-II in the 4th slot makes a great workhorse turret, and nice in that the wider AFOV of the Sterlings make them feel like mini-wide fields :grin:


You don't bother with the Sterling 20mm on the Turret? I suppose it made most sense to jettison that one to allow room for a shorter focal length eyepiece.

Just love their convenience. Also, they are killer sharp with that Baader 2.2x Barlow that is part of the BCO set. Was out this morning with that arrangement on my TSA observing Orion and the Perseus Double and Jupiter, and the Moon last evening - Nirvana :grin: :grin:


I've never tried the Sterlings for Jupiter or the Moon. I'm used to Orthos, XO's or TV Plossls for those objects.

Mike

#23 dbowlin

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Posted 15 October 2013 - 10:06 PM

I like my ES 82's so much I have thought about selling my UO HD's? But I have more testing to do. Time will tell.
Dale

#24 BillP

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Posted 16 October 2013 - 08:03 AM

Hi Collin. Yup, of all the Meade 5000/ES82s from 18mm and shorter, I liked the 8.8 the best. The preferences was not because of any specific testing, but just a general impression from use over time. I just kept coming back to that particular eyepiece while observing and always feeling that its FOV was the best corrected and the most engaging. Always loved the view it put up.

Since the OP though wants a planetary eyepiece, then with his scope something along the lines of a 7mm focal length (143x and .7mm exit pupil) would probably be best. So the 6.7mm would probably be the best option if he wants to keep it an 82 degree. I would go the traditional route myself though since teasing out the best the eyepiece can get is important for me and get a 7mm Ortho (Hutech, Fujiyama, UO HD). Might be handy to have an 8mm around also for when the seeing not as good. Basically IMO 6mm, 7mm, 8mm would be the perfect planetary trio for this scope that would get the most mileage. So in current marketplace of new stuff, probably the Fujiyama 6mm and 7mm Orthos, then the 8mm Brandon (or alternatively the TV 8mm Plossl if couldn't afford the Brandon).

#25 photiost

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Posted 16 October 2013 - 08:21 AM

There are many very good used Orthos to choose from and if you are patient also look at the used market for TV plossls, Celestron Ultima Plossls, and Meade series 4000 (Japan) .

For someone on a budget these are excellent eyepieces and coupled with a TV Powermate barlow you will get excellent results on your 102mm refractor.

Remember your scope is limited to about 300x on very good nights and you will find most nights your max will be around 150x to maybe 200x (depending on your site) so choose your eyepiece and barlow set with this in mind.

Enjoy your scope !! :cool:
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