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Eyepieces for XT10i (again)

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#1 tnranger

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Posted 08 January 2013 - 04:50 PM

Sorry to beat a dead horse, but I'm still trying to make good eyepiece choices.
We have used the stock 25 and 10mm Orion eyepieces on our XT10i for a year now. The views are OK, I just wonder if they could be better. Should I approach this as though I am going to replace these eyepieces, or just fill in the gaps? I'm looking at the Explore Scientific 68/82 degree eyepieces (along with everybody else).

Thanks.

#2 mmclure

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Posted 08 January 2013 - 05:08 PM

The stock 25mm plossl is not a bad eyepiece to keep. Although the 50 degree (or so) field of view is nothing to write home about, it gives pretty nice views. If you were to replace it, look at the ES 68 24mm

The 10mm, although similar optically, has quite short eye relief (6.5mm) so is difficult to use. I never use mine since I bought my 11mm ES 82 degree eyepiece (my favorite eyepiece in my XT10i.) The 11mm ES 82 gives a much wider field of view, sharper stars towards the edge, and is more comfortable to use. The only disadvantage vs the 10mm plossl is that it's bigger and heavier.

If you were to replace the 25mm plossl, the 20mm ES 68 or the 18mm ES 82 would be a good option, both giving you a bigger field of view than the 25mm plossl and more magnification. The 18mm 82 has two disadvantages that would have made me buy the 20mm 68 if it had been available when I bought the 18mm - the eye relief is quite short, and it's a 2" vs. a 1.25" eyepiece, which makes it a little more of a pain to switch to.

#3 JohnMurphyRN

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Posted 08 January 2013 - 05:08 PM

I'd go as wide as possible - 30mm ES 82, and something a bit more power than the 10, maybe ES 82 6.7mm. Or possibly Es 82 11mm + barlow.

#4 tnranger

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Posted 08 January 2013 - 05:25 PM

Thanks Manual,
I've struggled with the whole 1.25" vs 2" thing. Does anybody ever Barlow a low power eyepiece?

#5 sopticals

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Posted 08 January 2013 - 05:55 PM

Sorry to beat a dead horse, I'm looking at the Explore Scientific 68/82 degree eyepieces (along with everybody else).

Thanks.


Go with the flow, (everybody :grin: else).I can certainly recommend the ES82 series. The ones I have,(see my signature) are :jump: excellent.

Stephen.(44deg.S.)

#6 csrlice12

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Posted 08 January 2013 - 06:26 PM

+2, Love my ES eyepieces. Although my Naglers are older, the ES 82s perform all as well as they do in my 10XTi. They also work well in my refractor! If you have to choose, go for the 82*. I've not looked thru one of the new ES 82 24mm or 30mm as mine are the older nonwaterproof, size and weight of a neutron star (the 30mm is 3.08lbs). Same lens setup, different body and the pureness of mother natures air allowed to pass gently along the curves of the lenses, no purging here. But the views, WOW. All my others are the newer N2 (Ar in the 68*)purged versions. Love the 24mm; the lagoon nebula is framed beautifully in it, Andromeda---wow (and the 30mm too). The 18mm is a good eyepiece, great views, but its one I tend to skip. The 14mm I have works fine, great views; but some have experienced some field curvature with it. The 11mm--bound to become one of those eyepieces that everyone will want in their kit--one of those rare eyepieces that just outperforms everything else around it (it's all as good as the Nagler). The 8.8mm, mine is the one that has the flaring (correctable with a felt disk), but once in view, it's given me the best views of Jupiter so far; same with Saturn. At first the flaring bothered me, but then, how many times am I going to be trying to view something right next to the moon (no flaring on Jupiter)??? The 8.8 is quickly becoming a favorite (maybe I'll install that felt disk). The 6.7mm I've only been able to use a couple of times, and even then, that was at the limits of viewing conditions; but I do know Saturn looked particularly nice in it last summer. They're still collecting heavy metals created by exploding stars in the evolutionary construction of my 4.7mm and the ES68* 24mm. They did send me a sample of some of the materials they've gathered so far in the mail the other day. I understand some of the shipments have began turning up though.

#7 CosmoSat

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Posted 08 January 2013 - 10:46 PM

I've struggled with the whole 1.25" vs 2" thing. Does anybody ever Barlow a low power eyepiece?


A 25mm plossl eyepiece in the 10" f/5 scope will produce a 5mm exit pupil, 1 degree true field of view and 50x magnification. Do you really want to go lower than that? If at all u want to replace the 25mm plossl, I would suggest u the ES24 68 degree in the 1.25mm barrel size giving a 1.3 degree field. The 24mm 82 gives a 1.6 degree true field of view but at almost twice the cost. Many find it a hassle to change back and forth from a 1.25" to a 2" just for the one eyepiece.

The other eyepiece I would suggest u would be the ES11mm 82 for Deep sky observing with the 2mm exit pupil u will get at about 110x.

Clear Skies!

#8 mfromb

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Posted 09 January 2013 - 12:39 AM

We have used the stock 25 and 10mm Orion eyepieces on our XT10i for a year now. The views are OK, I just wonder if they could be better. Should I approach this as though I am going to replace these eyepieces, or just fill in the gaps?


I'm not an eyepiece expert (newb, still on training wheels), but I will offer some free advice at a reasonable discount. Maybe not advice, really, but just my own train of thought as you seem to be toying with the idea of replacing the 10mm plossl (vs. augmenting it).

It took me about 10 minutes of viewing, and one quick set of peeks from my wife/kids, into the 10mm plossl to declare it a non-starter for us to 'enjoy' using. Sure... it could be pressed into service. But none of us were really ENJOYING the task of pressing our eyeball near to the surface and peering into a relatively tiny hole to try and steal fleeting views of a planet.

So, with a couple of key characteristics on the wish list (primarily more eye relief!, and larger field of view to prolong the views between scope movement), I opted for the ES82 11mm.

I took the 11mm over the 8.8 or 6.7 as a replacement for a few reasons:

* It would be emminently usable (109x on my XT8i) on pretty much any viewing night short of 'bad', here in my locale -- as best as I could determine.

* It would barlow (2x) to a respectable 218x for nights of good seeing, as opposed to one of the others barlowed to an even higher mag, which would likely lead to even less frequent usability.

* If I married the 11mm to a 2x barlow that also affords an approximate 1.5x option (unscrew the bottom lens, screw onto EP filter threads), I could also get a good middling point of 160x-ish, which might be more frequently usable than 218x.


I opined that the 8.8, native, would be usable on most nights as well... but barlowed, it would hit the ceiling very quickly and be less frequently useful (1.5x and 2x both in excess of 200x).

The 6.7, native, would have a starting point (179x) that might be pushing past useful on too many nights, and barlowed it would only see the light of a planet on the really exception nights of seeing. I certainly didn't want an EP that would sit idle on so many nights. I wanted to replace the 10mm plossl. The 6.7, and to a lesser degree the 8.8, would put me back in the cruel hands of the 10mm plossl that I wanted to retire from service.

So, the 11mm struck the sweet spot, for me, serving as an emminently usable, direct replacement.

Your conditions may dictate different degrees of usability for the mags these EPs (with and without barlow) would yield.

Rather than augment the 10mm, I chose to replace it. Later, I can look to add more magnification. In the meantime, I'm wearing out the 11mm. With the 2x/1.5x barlow, it's finding its way into the scope every night out. You needn't wonder if the views could be better. They most certainly can be. :)

The 25mm I am less hurried to replace. It's actually not bad (in my unlearned opinion). I've had some good views with it, thus far, it's not uncomfortable to use (unlike the 10mm), and therefore its not clamoring for a replacement as quickly as the 10mm was. I do have an ES68 24mm on order... which I figured was more like getting in line for an eventual replacement, given the constrained supply of them at the moment. In the meantime, I don't mind using the 25mm.

In the end, it is of course up to you if you wish to replace the 10mm and/or the 25mm, or 'fill in' the gaps. I'm very happy to have replaced the 10mm. My whole family is enjoying improved views in the ES82 11mm.

#9 Peshmerga

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Posted 09 January 2013 - 03:38 AM

I have the same starting eyepieces as you, 25mm and 10mm Orion Sirius Plossls. However I'm using an XT8i.

I would recommend replacing the 10mm with an 11mm ES82. The 10mm's eye relief is insanely tiny, plus it's like looking through a pinhole. Or you could just keep the 10mm and buy a 2x barlow for high magnification. Improves eye relief a bit too. You could also purchase the 11mm ES82 and 2x barlow or 6.7mm and 11mm ES82 instead. :grin:

On the low power end, keep the 25mm Plossl. I use mines as a finder eyepiece. I do have a 2-inch 30mm ES82, but find the bulk to be bit cumbersome. Especially when changing eyepieces. Though it does fit the entire Pleiades star cluster just barely, which is quite nice.

#10 csrlice12

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Posted 09 January 2013 - 08:42 AM

My 10mm plossel has been relegated the distinct honor to be the most used eyepiece in my collection. Every time I go out, I use it.....to align my finderscope and perform the two star alignment....then it's back into the kit. Yes, it's eye relief is too tight to be of use for anything else. The 25mm that came with the scope though was pretty good.

#11 tnranger

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Posted 09 January 2013 - 10:38 AM

VERY helpful replies all.

I now realize how little eye relief that stock 10mm has. Reminds me of using binoculars.

For now, my first purchase will be the ES82 11mm, and a good 2X Barlow.

For later, what would be a good high power eyepiece, the 8.8mm or the 6.7mm?

#12 aa5te

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Posted 09 January 2013 - 10:48 AM

For now, my first purchase will be the ES82 11mm, and a good 2X Barlow.

For later, what would be a good high power eyepiece, the 8.8mm or the 6.7mm?

The 11mm with the 2x barlow will provide more magnification than the 6.7mm will. Maybe you're trying to prevent using the barlow (which is understandable)? I use a Meade 5000 series 4.7mm UWA in my 10" f/5 dob with success, but sometimes it provides too much power due to poor/mediocre seeing.

#13 CosmoSat

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Posted 09 January 2013 - 11:15 AM

For ur f/4.7 dob the 4.7mm eyepiece will provide a 1mm exit pupil and about 250x magnification which is considered good for observing details and will help more so with planets. Coupled with a 1.5x/2x barlow lens it will give u 375x and 500x which is the accepted as the highest useful for a 10" telescope.

Clear Skies!

#14 JohnMurphyRN

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Posted 09 January 2013 - 12:31 PM

VERY helpful replies all.

I now realize how little eye relief that stock 10mm has. Reminds me of using binoculars.

For now, my first purchase will be the ES82 11mm, and a good 2X Barlow.

For later, what would be a good high power eyepiece, the 8.8mm or the 6.7mm?


I suspect you'll be happy with the 11mm + barlow and have no need of a higher power EP.

#15 gregory93

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Posted 09 January 2013 - 12:35 PM

They're still collecting heavy metals created by exploding stars in the evolutionary construction of my 4.7mm and the ES68* 24mm. They did send me a sample of some of the materials they've gathered so far in the mail the other day. I understand some of the shipments have began turning up though.

You made my day,sir! :lol: :lol:

#16 frito

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Posted 09 January 2013 - 10:10 PM

VERY helpful replies all.

I now realize how little eye relief that stock 10mm has. Reminds me of using binoculars.

For now, my first purchase will be the ES82 11mm, and a good 2X Barlow.

For later, what would be a good high power eyepiece, the 8.8mm or the 6.7mm?


I suspect you'll be happy with the 11mm + barlow and have no need of a higher power EP.


i aqgree.

my currently most used eyepieces in my XT10 are 38mm Q70 for widefield views and finding objects. 16mm T5 Nagler and 11mm ES 82 along with my 2x barlow for when i need more magnification. in the past week i've had some breathtaking views of jupiter in both the nagler and the ES coupled with my Orion "shorty" 2x barlow, i don't really think i need any higher mag than what that provides but if a deal springs up for a 5-6 mm 82 deg TV or ES i'll probably pick one up other than that the only thing i'm thinking of getting now is something like a 24 or 27mm panoptic or more likely as it will be cheaper something in that range in the ES 68 range.

#17 Scanning4Comets

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Posted 10 January 2013 - 06:26 AM

frito,

I'll agree that the 38mm Orion Q-70 is a great finder EP! Eye placement on it is excellent, but I really noticed how bad the edges were once a friend of mine pointed it out, so I sold mine and now have a 34mm ES 68. I've only tried it twice because skies have been less than ideal here lately.

I may still spring for a 30mm ES 82 and get rid of this one. I need good correction and the 30mm ES 82 will probably do it! :jump:

#18 tnranger

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Posted 10 January 2013 - 09:46 AM

The ES82 11mm is ordered and on the way.

Thanks for all the great discussion.

#19 csrlice12

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Posted 10 January 2013 - 09:51 AM

Don't know your age, but if you're a little older (I'm 59), I find the ES82* 24mm an easier to use eyepiece then the 30mm. It's not the weight as the 10XTi can handle either, its more the FOV. The 24mm frames things nicely like Andromeda and especially the Lagoon Nebula, the 30mm just has too large an FOV for me. Nice eyepiece though, if you're younger the 30mm will be ok. I do keep the 30mm though for those really large objects like Andromeda and to fit the Pleades into the FOV of the 10"

#20 frito

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Posted 10 January 2013 - 11:04 AM

frito,

I'll agree that the 38mm Orion Q-70 is a great finder EP! Eye placement on it is excellent, but I really noticed how bad the edges were once a friend of mine pointed it out, so I sold mine and now have a 34mm ES 68. I've only tried it twice because skies have been less than ideal here lately.

I may still spring for a 30mm ES 82 and get rid of this one. I need good correction and the 30mm ES 82 will probably do it! :jump:


yeah in an F/4.7 the Q70 really starts to live up to its bad reputation but as a finder EP it's still not that bad. it was a great EP in my XT8 (F/6) and it was pretty good in a 12" lightbridge as well (F/5)

#21 Scanning4Comets

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Posted 10 January 2013 - 12:13 PM

the 30mm just has too large an FOV for me.


I'll take it if you don't want it! I always wanted to try that one out. :lol:

Cheers,

#22 sopticals

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Posted 10 January 2013 - 08:51 PM

frito,

I may still spring for a 30mm ES 82 and get rid of this one. I need good correction and the 30mm ES 82 will probably do it! :jump:


It will, for :bow: sure.






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